As a fundamental pillar for fostering new quality productive forces, constructing
a modern industrial system and safeguarding national comprehensive security, the new
materials industry underpins the core competitiveness of high-end manufacturing and
cutting-edge technologies. Today's global industrial landscape is undergoing profound
restructuring driven by four pivotal forces：intensifying geopolitical competition,
worldwide carbon peaking and carbon neutrality transitions, in-depth integration of
digital and intelligent technologies, and targeted iteration of materials spurred
by diverse downstream application scenarios. In parallel, artificial intelligence,
big data and high-throughput computing are revolutionizing the traditional trial-and-error
R&D paradigm of materials science, enabling data-driven material screening, inverse
structural design and intelligent process optimization to drastically cut research
cycles and experimental costs. This paper systematically sorted out the opportunities
and structural risks confronting the global new materials industry, and thoroughly
reviewed the strategic arrangements rolled out by the United States, the European
Union, Germany, the United Kingdom, Japan and Russia in 2025 and 2026. U.S. tied new
materials closely to national defense and technological security, launching special
programs including Crystal Palace and Carbon Crunch for military advanced materials,
and consolidated independent supply chains for semiconductor materials through the
CHIPS and Science Act, alongside initiatives to supervise critical mineral resources
and apply AI to accelerate material innovation. EU centered its strategy on European
strategic autonomy and green transformation, advancing the Advanced Materials Act
and the Critical Raw Materials Act to diversify mineral supply, developed circular
materials and set global green trade standards. Germany, UK, Japan and Russia had
also introduced targeted national plans respectively, focusing on technological sovereignty,
digitalized material R&D, military-civilian integrated innovation, rare earth recycling
and import substitution amid geopolitical sanctions. After years of policy support
and technological accumulation, China had achieved remarkable breakthroughs in lithium
battery materials, rare earth functional materials and general carbon fibers, with
a batch of national key innovation platforms and specialized sophisticated enterprises
cultivated. Nevertheless, prominent internal and external vulnerabilities persisted.
Externally, fierce global technological competition and restrictive trade policies
created severe "bottleneck" risks, as high-end photoresists, single-crystal superalloys,
core manufacturing equipment and other strategic materials still relied heavily on
imports, and China lacked sufficient discourse power in formulating international
material standards. Targeting six core strategic fields with prominent security risks,
this study proposed targeted development frameworks for self-reliant industrial construction.
For micro-nano electronic manufacturing, it highlighted localized substitution of
bottleneck materials such as photoresists and electronic specialty gases, alongside
R&D of low-dielectric materials and wide-bandgap semiconductor supporting materials
to match advanced packaging and high-performance chip demands. For aerospace, it advocated
full-chain independent manufacturing of high-performance carbon fibers, single-crystal
superalloys and ceramic matrix composites to satisfy extreme service conditions of
hypersonic vehicles and reusable rockets. For robotics and sensors, priorities covered
lightweight structural alloys, rare earth permanent magnets and flexible sensing materials
to support bionic robots and precision perception systems. In advanced nuclear energy,
the paper stressed breakthroughs in radiation-resistant cladding materials and low-activation
structural alloys to support fourth-generation reactors and space nuclear power sources.
For marine engineering equipment, corrosion-resistant high-strength steel and deep-sea
functional materials were key to advancing polar vessels and offshore renewable energy
infrastructure. To systematically resolve industrial security challenges, this paper
put forward multi-dimensional countermeasures covering five core dimensions. First,
innovation-driven development shall be strengthened via the new whole-of-nation system
to tackle generic bottleneck technologies, improve the commercialization system of
scientific achievements and optimize intellectual property management for strategic
materials. Second, supply chain resilience would be reinforced through domestic mineral
exploration, diversified cross-border resource cooperation, national strategic mineral
reserves and digital risk early warning platforms. Third, an integrated standard system
aligned with international norms shall be established to fill standard gaps in high-end
materials and implement full-lifecycle quality traceability management. Fourth, a
multi-level talent training matrix would be optimized through industry-university-research
integration, performance evaluation reforms and market-oriented incentive mechanisms
to address talent shortages. Fifth, the industrial ecosystem would be upgraded through
targeted policy support for industrial clusters, intelligent production line transformation
and low-carbon circular manufacturing to advance high-end, intelligent and green development
simultaneously. In summary, the safety of the new materials industry constituted an
indispensable foundation of national industrial and scientific security. Faced with
sweeping global industrial reshuffling and fierce international competition, China
must advance coordinated upgrades across technological innovation, supply chain robustness,
standardization, talent cultivation and industrial ecology. The conclusions and suggestions
of this research could provide theoretical reference and practical guidance for constructing
an independent, controllable, safe and efficient new materials industrial system,
consolidating the bottom line of national scientific and industrial security, and
fueling the steady growth of new quality productive forces and the advancement of
new industrialization.
Show more
Aluminum alloys are widely appliedd in the aerospace industry due to their excellent
mechanical properties, superior corrosion resistance, good machinability, high strength
to density ratio, and desirable electrical and thermal conductivity. So far, the aluminization
application ratio of civil aircraft exceeds 70%, while that of military aircraft is
more than 48%. Among them, the second series of aluminum alloys （Al, Cu, Mg）, as heat-treatable
strengthend aluminum alloys, have excellent mechanical properties. Therefore, they
are widly used as aircraft structural materials. In recent years, 2324 aluminum alloy
has been optimized by regulating the content of alloying elements and optimizing heat
treatment processes, endowing it with excellent mechanical properties. After aging
treatment, the second phases mainly include S', S and T phases. It is notable that
S phase acts as the main strengthening phase at room temperature for 2324 aluminum
alloy. T phase is the high-temperature strengthening phase, which is a brittle phase
at room temperature and there by deteriorates the comprehensive performance of the
alloy. In-depth researchon S-phase can help to improve the performance of 2324 aluminum
alloy. In this paper, the strain field and nucleation process around S-phase in 2324
aluminum alloy were systematically studied. With transmission electron microscopy
（TEM） and differential scanning calorimetry （DSC）, the strain field and nucleation
kinetics around S-phase during aging were investigated. The strain field around S-phase
and its intrinsic characteristics were revealed, and the relationship between activation
energy and transformation fraction, as well as nucleation mechanism of S-phase, were
elucidated. The results showed that a strong stress field existed around the early-formed
S-phase, and the stress magnitude decreased with the increasing distance from S-phase.
The size of S-phase also affected the surrounding stress field, and the smaller the
width of S-phase, the higher the surrounding stress field. On the one hand, S-phase
was incoherent with the alloy matrix, the lattice mismatch between the two phases
induced the formation of a stress field. The calculated lattice mismatch were –1.25%,
1.92%, and –1.45% for ［100］S//［100］Al, ［010］S//［012］Al, ［001］S//［021］Al, respectively. On the other hand, there were diffused Cu/Mg atoms around S phase,
and the concentration of diffused atoms was distributed in a gradient along the direction
away from S-phase. In general, the concentration of Cu/Mg atoms was high in the region
close to S-phase and low in the region far away from it. Since the atomic sizes of
Cu and Mg atoms differed greatly from that of the aluminum atoms of the matrix, a
stress field was formed around S-phase. In summary, the stress field around S-phase
resulted fromthe superposition of two contributions：the stress field generated by
the lattice mismatch and Cu/Mg solute atoms. Moreover, all characteristic temperatures
of S'-phase increased with rising heating rate, indicating that the formation and
dissolution of S' and S-phase were controlled by the reaction kinetics and exhibited
thermal activation characteristics. In addition, the magnitude of precipitation decreased
as the increase of the heating rate, which could be explained by the enhanced solid
solubility of Cu at a higher heating rates. The average values of the activation energies
for the precipitation of S' and S-phases calculated by Kissinger method were 76.65
and 119.57 kJ·mol−1, respectively, and corresponded to vacancy migration energies of 41 and 66.9 kJ·mol−1 in Al-Cu-Mg alloy, respectively. Therefore, the precipitation of S' and S phases
was governed by multiple factors rather thanmerley the diffusion of Cu atoms. Then,
as the heating rate increased, the temperature was higher for the transformation fraction,
indicating that the transformation degree increased with the rising heating rate and
temperature. These features could be explained from two aspects：1） at a certain heating
rate, the diffusion of solute atoms was enhanced with increasing temperature, thereby
promoting the transformation； 2） at a fixed temperature, as the heating rate decreased,
the solute atoms had enough time to diffuse, thus increasing the transformation fraction.
The apparent activation energies E calculated by the Analytical method were 84.98 and 148.53 kJ·mol−1 for S and S' phases, respectively. The activation energy required for S'-phase formation
decreased with the increase of transformation fraction, and the activation energy
during the formation of S-phase increases with the increase of the conversion rate.
The decreasing activation energy of S'-phase was due to the gradual increase in the
nucleation sites during aging. The increase in S-phase activation energy was due to
the decrease in alloying elements and dislocations in the matrix with prolonged aging,
making the nucleation of S-phase increasingly difficult and requiring higher activation
energy. In conclusion, the activation energy of S'-phase decreased with the increase
of the transformation fraction, and the activation energy of S-phase increased with
the increase of the transformation fraction.
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Ti-6Al-4V（TC4）, as an excellent dual-phase titanium alloy, exhibits good thermal stability
at high temperatures and possesses superior overall performance, leading to its extensive
use in the aerospace industry. Due to the complex geometries and poor room-temperature
formability of titanium alloys, hot forming processes are typically employed during
manufacturing. However, TC4 alloy has a narrow hot working window, where the microstructure
is highly sensitive to deformation parameters. The competition among deformation mechanisms
such as dynamic recrystallization（DRX）, work hardening（WH）, and dynamic recovery（DRV）complicates
microstructural evolution during high-temperature deformation. Therefore, investigating
the effects of deformation parameters on microstructural evolution and corresponding
deformation mechanisms is crucial. Traditionally, hot compression tests are used to
evaluate alloy forming processes. However, in the complex process of hot stamping
of intricate parts, tensile stresses may lead to accumulated damage, significantly
reducing final mechanical performance. High-temperature tensile tests accurately reflect
the stress state during material deformation. The tensile deformation behavior of
titanium alloys differs in mechanism from hot compression, making it essential to
elucidate the evolution of microstructure during high-temperature tensile deformation
for a better understanding of mechanical property changes. Previous studies have indicated
that high-temperature deformation of TC4 alloy involves complex microstructural changes
such as processing hardening due to dynamic grain growth, deformation and high-temperature
movement of intragranular dislocations, α→β phase transformation, globularization
of lamellar α phase, dynamic recovery, and dynamic recrystallization. Consequently,
material mechanical properties undergo intricate changes, necessitating exploration
of TC4 titanium alloy's mechanical characteristics under different high-temperature
conditions. The plastic deformation capability of the alloy fundamentally reflects
the macro results of its internal microstructural deformation mechanism. A systematic
study on the tensile deformation behavior of TC4 alloy within a broad temperature
range for hot forming is currently lacking. Therefore, this paper conducted high-temperature
tensile experiments at temperatures of 650, 700, 750, 800 and 850 ℃ with a strain
rate of 0.02 s-1, employing electron backscatter diffraction （EBSD） to analyze the tensile microstructure
characteristics and deformation mechanisms of TC4 alloy post-deformation. The formation
process of recrystallized grains was reflected by changes in orientation difference
angles, and individual grains were selected to analyze the globularization process
of lamellar structures. The phase diagrams and image quality maps were used to reveal
α-β phase transformation of TC4 alloy. The results showed that：1） TC4 alloy exhibited
different deformation characteristics during high-temperature tensile processes. With
increasing deformation temperature, yield stress gradually decreased. At 650 ℃, yield
stress increased with loading, peaks, and then rapidly decreased until fracture, exhibiting
significant work hardening characteristics. At 700 and 750 ℃, yield stress reached
a maximum early in deformation, followed by dynamic softening, indicating DRV characteristics.
At 800 and 850 ℃, yield stress peaked early in deformation and then decreased gradually
with increasing strain, where dynamic recrystallization played a dominant role, resulting
in decreased strength and significantly increased elongation. 2） Fracture surface
analysis revealed that at lower temperatures, dimples were smaller and deeper, with
uneven distribution and presence of microcracks and numerous voids at fracture surfaces.
As temperature increased, dimples became larger and shallower, indicating increased
plasticity, consistent with macro trends in elongation. 3） During high-temperature
deformation of TC4 alloy, significant differences were observed in microstructural
morphology. At 650 ℃, primary α phase exhibited elongated distribution with relatively
low equiaxed transformation. Local recrystallization occurred in grain boundaries
of α-p phase, forming "necklace-like" recrystallized grains. As temperature rose to
700 and 750 ℃, dynamic softening did not fully dissipate energy from thermal deformation,
leading to dynamic precipitation of lamellar α phase, with increased thickness of
lamellar α phase with temperature rise. At 800 ℃, thinner α phase lamellae transformed
into finer recrystallized grains, undergoing dynamic globularization process, with
average DRX grain size approximately 1.04 μm. Increasing to 850 ℃, volume fraction
of recrystallized grains increased, including those formed at α-p phase grain boundaries
and globularization of lamellar α phase. Overall, with increasing tensile temperature,
primary α phase tended towards equiaxial transformation, decreasing aspect ratio from
1.67 to 1.35, with grain size initially increasing and then decreasing. Low-angle
grain boundaries（LAGBs）gradually transformed into high-angle grain boundaries（HAGBs）,
with HAGBs content increasing from 11.7% to 36.1%, indicating enhanced DRX effects.
High-temperature tensile process of TC4 alloy was controlled by multiple deformation
mechanisms, primarily including DRV mechanism, DRX mechanism, α→β phase transformation,
lamellar α phase globularization mechanism, and grain boundary sliding（GBS）mechanism.
DRV and continuous dynamic recrystallization（CDRX）mainly controled flow softening
process of TC4 alloy, with CDRX mechanism continuously transitioning from LAGBs to
HAGBs. Discontinuous dynamic recrystallization（DDRX）phenomenon was observed even at
lower temperatures（650 ℃）. α→β phase transformation was a critical factor in enhancing
alloy plasticity, with decreasing volume fraction of αp phase and increasing α→β phase transformation with temperature rise. Dynamic globularization
of lamellar α phase initially occurred in thinner lamellar layers, eventually forming
fine and uniform DRX grains.
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Given the challenges posed by the low hardness and inadequate wear resistance of Ti-6Al-4V
alloy, this research aimed to explore an innovative solution by employing the laser
cladding technique to develop high-entropy alloy（HEA）coatings composed of TiZrNbCrCo
on the alloy's surface. The primary objectives were to investigate the effects of
varying the number of cladding layers on the elemental composition and to assess how
these variations influenced the phase constitution, microstructure, microhardness,
wear, and electrochemical properties of HEA coatings. To predict the phase composition
of the solid solution phases in HEA coatings with different layer numbers, empirical
thermophysical parameters were utilized. The methodology encompassed a detailed experimental
setup where the laser cladding process was meticulously optimized to fabricate coatings
with varying numbers of layers. This approach enabled the controlled manipulation
of the dilution rate and elemental distribution within the coatings, thereby allowing
for a comprehensive analysis of the resulting phase and microstructural characteristics.
The coatings were systematically analyzed using X-ray diffraction（XRD）to identify
their phase compositions and scanning electron microscopy to elucidate their microstructures.
Microhardness measurements were conducted to evaluate the mechanical enhancements,
while wear tests were performed to assess the wear resistance of the coatings. Furthermore,
electrochemical tests in a 3.5%NaCl solution were carried out to determine the coatings'
corrosion resistance. The results revealed that all coatings, exhibited a consistent
phase composition, predominantly featuring a body-centered cubic （bcc） structured
solid solution phase. This phase was characterized by dendrites rich in Nb and inter-dendrites
rich in Co. It was observed that an increase in the number of cladding layers led
to a decrease in the dilution rate, which in turn facilitated the formation of petal-like
Laves phases enriched in Co and Zr, along with α-Ti precipitates enriched in Zr. Remarkably,
the average microhardness of the coatings reached HV0.1747.7, approximately 2.33 times that of the substrate. This significant enhancement
in microhardness translated to a reduction in wear volume by 68.6% compared to the
substrate. The optimal corrosion resistance was achieved with a two-layer configuration,
which exhibited the lowest self-corrosion current （6.46×10−6 A·cm−2） a larger self-corrosion potential （-0.286 V）, and the lowest corrosion rate, indicating
a substantial improvement in corrosion resistance. The conclusion drawn from this
study highlighted the critical role of laser cladding parameters in influencing the
microstructural and compositional characteristics of HEA coatings. The enhancement
in mechanical and chemical properties could be attributed to the strategic manipulation
of the number of cladding layers, which optimized the microstructural features such
as the distribution of Laves phases and α-Ti precipitates. Moreover, this research
contributed to the broader academic discourse by elucidating the relationship between
laser cladding parameters, microstructural evolution, and the resulting properties
of HEA coatings. In summary, this comprehensive investigation into the development
and characterization of TiZrNbCrCo high-entropy alloy coatings on Ti-6Al-4V alloy
surfaces provided a promising approach for addressing the limitations of conventional
titanium alloys. The research outcomes not only demonstrated the feasibility of significantly
enhancing the hardness, wear, and corrosion resistance of Ti-6Al-4V alloys through
laser cladded HEA coatings but also opened up opportunities for using high-entropy
alloys in surface engineering to meet the needs of modern industries.
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Silicon(Si)-based anodes are widely recognized as the most promising alternatives
to conventional graphite anodes for lithium-ion batteries(LIBs), owing to their ultrahigh
theoretical specific capacity(4200 mAh·g-1), lowlithiation potential, abundant crustal reserves, low toxicity, and cost-effectiveness.
However, their large-scale commercialization is severely hindered by two intrinsic
challenges：1) drastic volume expansion(>300%)during lithiation/delithiation, which
induces particle pulverization, electrode integrity degradation, and continuous rupture/reformation
of the solid electrolyte interphase(SEI)films, thereby causing irreversible lithium-ion
consumption； 2) extremely low intrinsic electrical conductivity(1×10-4 S·cm-1), which restricts ion/electron transport kinetics and thus degrades rate capability.To
address these issues, early research efforts focused on nano-engineering of Si and
the development of Si-based composites. Nanostructured Si can partially alleviate
mechanical fracture by accommodating strain through size-dependent deformation mechanisms；
however, it tends to agglomerate during prolonged cycling and exhibits excessive side
reactions with the electrolyte, reducing the initial Coulombic efficiency(ICE)and
cycling lifespan. Si/carbon(Si/C)composites design, which take advantage of the high
electrical conductivity, chemical stability, and mechanical flexibility of carbon
matrices, have emerged as a primary route toward commercialization. Nevertheless,
challenges related to the inherently low conductivity of Si and inadequate interfacial
bonding between Si and carbon remain unresolved. Against this backdrop, this review
emphasized doping modification as a fundamental strategy to enhance the electrochemical
performance of Si-based anodes. Starting from the lithium storage mechanism of Si—which
stored lithium via an alloying/dealloying reaction to form various Li-Si alloys, with
a theoretical maximum lithiation phase of Li22Si5 accommodating 4.4 Li atoms per Si atom—and its core limitations, we systematically
analyzed the regulation mechanisms and functional effects of different doping approaches.
These were categorized into three types：non-metallic (heteroatom) doping, metallic
doping, and multi-element co-doping. Non-metallic doping(e.g., with B, P, N, or S)effectively
modulated the electronic structure of Si-based materials, improved Li+ transport pathways, enhanced electronic conductivity, and promoted the formation
of a more stable SEI layer. Metallic doping was subdivided into two categories：electrochemically
inactive metals(e.g., Fe, Ti), which enhanced electrical conduction and provided mechanical
reinforcement to alleviate volume expansion, and electrochemically active metals(e.g.,
Mg, Ge), which contributed additional capacity and helped accommodate volume expansion
through synergistic alloying behavior. Multi-element co-doping(including non-metal/non-metal
and metal/non-metal combinations)achieved synergistic optimization of multiple physicochemical
properties, thus further enhancing conductivity, structural stability, and fast-charging
performance. Finally, this review outlined future perspectives for doping modification
technologies in Si-based anodes, including the exploration of novel co-doping systems
to simultaneously address conductivity, volume expansion, and SEI stability； the optimization
of doping processes for precise control over elemental distribution and concentration；
and the integration of in-situ characterization techniques to deepen the understanding
of the influence of doping elements on the lithium storage mechanism. This review
aimed to provide fundamental theoretical insights and practical technical guidance
for the development of high-energy-density and fast-charging Si-based anode materials,
thereby accelerating their commercial adoption.
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As a fundamental pillar for fostering new quality productive forces, constructing
a modern industrial system and safeguarding national comprehensive security, the new
materials industry underpins the core competitiveness of high-end manufacturing and
cutting-edge technologies. Today's global industrial landscape is undergoing profound
restructuring driven by four pivotal forces：intensifying geopolitical competition,
worldwide carbon peaking and carbon neutrality transitions, in-depth integration of
digital and intelligent technologies, and targeted iteration of materials spurred
by diverse downstream application scenarios. In parallel, artificial intelligence,
big data and high-throughput computing are revolutionizing the traditional trial-and-error
R&D paradigm of materials science, enabling data-driven material screening, inverse
structural design and intelligent process optimization to drastically cut research
cycles and experimental costs. This paper systematically sorted out the opportunities
and structural risks confronting the global new materials industry, and thoroughly
reviewed the strategic arrangements rolled out by the United States, the European
Union, Germany, the United Kingdom, Japan and Russia in 2025 and 2026. U.S. tied new
materials closely to national defense and technological security, launching special
programs including Crystal Palace and Carbon Crunch for military advanced materials,
and consolidated independent supply chains for semiconductor materials through the
CHIPS and Science Act, alongside initiatives to supervise critical mineral resources
and apply AI to accelerate material innovation. EU centered its strategy on European
strategic autonomy and green transformation, advancing the Advanced Materials Act
and the Critical Raw Materials Act to diversify mineral supply, developed circular
materials and set global green trade standards. Germany, UK, Japan and Russia had
also introduced targeted national plans respectively, focusing on technological sovereignty,
digitalized material R&D, military-civilian integrated innovation, rare earth recycling
and import substitution amid geopolitical sanctions. After years of policy support
and technological accumulation, China had achieved remarkable breakthroughs in lithium
battery materials, rare earth functional materials and general carbon fibers, with
a batch of national key innovation platforms and specialized sophisticated enterprises
cultivated. Nevertheless, prominent internal and external vulnerabilities persisted.
Externally, fierce global technological competition and restrictive trade policies
created severe "bottleneck" risks, as high-end photoresists, single-crystal superalloys,
core manufacturing equipment and other strategic materials still relied heavily on
imports, and China lacked sufficient discourse power in formulating international
material standards. Targeting six core strategic fields with prominent security risks,
this study proposed targeted development frameworks for self-reliant industrial construction.
For micro-nano electronic manufacturing, it highlighted localized substitution of
bottleneck materials such as photoresists and electronic specialty gases, alongside
R&D of low-dielectric materials and wide-bandgap semiconductor supporting materials
to match advanced packaging and high-performance chip demands. For aerospace, it advocated
full-chain independent manufacturing of high-performance carbon fibers, single-crystal
superalloys and ceramic matrix composites to satisfy extreme service conditions of
hypersonic vehicles and reusable rockets. For robotics and sensors, priorities covered
lightweight structural alloys, rare earth permanent magnets and flexible sensing materials
to support bionic robots and precision perception systems. In advanced nuclear energy,
the paper stressed breakthroughs in radiation-resistant cladding materials and low-activation
structural alloys to support fourth-generation reactors and space nuclear power sources.
For marine engineering equipment, corrosion-resistant high-strength steel and deep-sea
functional materials were key to advancing polar vessels and offshore renewable energy
infrastructure. To systematically resolve industrial security challenges, this paper
put forward multi-dimensional countermeasures covering five core dimensions. First,
innovation-driven development shall be strengthened via the new whole-of-nation system
to tackle generic bottleneck technologies, improve the commercialization system of
scientific achievements and optimize intellectual property management for strategic
materials. Second, supply chain resilience would be reinforced through domestic mineral
exploration, diversified cross-border resource cooperation, national strategic mineral
reserves and digital risk early warning platforms. Third, an integrated standard system
aligned with international norms shall be established to fill standard gaps in high-end
materials and implement full-lifecycle quality traceability management. Fourth, a
multi-level talent training matrix would be optimized through industry-university-research
integration, performance evaluation reforms and market-oriented incentive mechanisms
to address talent shortages. Fifth, the industrial ecosystem would be upgraded through
targeted policy support for industrial clusters, intelligent production line transformation
and low-carbon circular manufacturing to advance high-end, intelligent and green development
simultaneously. In summary, the safety of the new materials industry constituted an
indispensable foundation of national industrial and scientific security. Faced with
sweeping global industrial reshuffling and fierce international competition, China
must advance coordinated upgrades across technological innovation, supply chain robustness,
standardization, talent cultivation and industrial ecology. The conclusions and suggestions
of this research could provide theoretical reference and practical guidance for constructing
an independent, controllable, safe and efficient new materials industrial system,
consolidating the bottom line of national scientific and industrial security, and
fueling the steady growth of new quality productive forces and the advancement of
new industrialization.
Show more
Specific heat capacity is a basic thermal physical parameter in the process of material
temperature rise，and it is also a key physical quantity in material design and application.
At present，the specific heat capacity of materials is tested mostly by the foreign
standard ASTM E1269 "Standard test method for Measuring specific heat capacity by
differential scanning calorimetry". The measured specific heat capacity is also called
sensible specific heat capacity because the material only changes in temperature without
phase transformation during the heating process. However，many metal materials are
usually composed of a variety of phases at room temperature due to design and use
requirements，and phase transformation will inevitably occur during the heating process，accompanied
by obvious thermal response and directly reflected in the specific heat capacity curve.
This part of the heat absorption or heat release due to phase transformation is called
latent heat，and the specific heat capacity obtained by calculation is the specific
heat capacity of latent heat. When the specific heat capacity of an unknown material
is tested according to the standard test method，the actual specific heat capacity
measured should be called the apparent specific heat capacity. That is because it
contains both sensible heat capacity and latent heat capacity，and the current test
standard does not mention how to distinguish between the two. When the material has
no thermal effect，the apparent specific heat capacity measured is the sensible specific
heat capacity. When the material includes thermal effect，the apparent specific heat
capacity is greater than the sensible specific heat capacity. In many test cases，the
apparent specific heat capacity was mistakenly considered as the sensible specific
heat capacity of the material，which made the specific heat capacity data value too
large，affecting the thermal conductivity characterization of the material. In this
paper，the specific heat capacity of In718plus was tested，and the phase transformation
in its curve was subjected to thermal insulation water quenching treatment and microstructure
analysis，the specific reasons were identified and the data processing method for obtaining
the sensible specific heat capacity was proposed. The specific heat capacity of In718plus
superalloy was measured by differential scanning calorimetry （DSC）. An obvious heat
absorption peak appeared during the heating process，resulting in an abnormal increase
in the specific heat capacity. After the original microstructure was heated at 700
℃ in Muffle furnace for 20 min，the η phase and the γ' phase in the grain boundary
did not change much. After the original structure was kept at 900 ℃ in Muffle furnace
for 20 min and water quenching，η phase on the grain boundary showed a tendency to
grow，and the number of γ' phase decreased significantly. Therefore，it could be concluded
that the main phase change occurring at the second peak on the DSC thermal analysis
curve was the enhanced phase γ' dissolution reaction，which belonged to the first-order
phase transition with latent heat. As reported in the literature，In718plus alloy was
developed on the basis of In718 alloy by adjusting the chemical composition，and the
strengthening phase was more stable γ' -Ni3（Ti，Al，Nb），which increased its service temperature from 649 to 700 ℃. On the DSC curve，the
phase transition peak started at 700 ℃ and ended at 900 ℃，which corresponded to the
dissolution range of γ' phase. When the sensible specific heat capacity of In718plus
itself was measured by DSC，the latent heat of γ' phase dissolution during the heating
process had nothing to do with the sensible heat of In718plus itself，and should be
distinguished in the test results. It was mentioned in literature that there was a
functional relationship between the specific heat capacity and temperature of metal
materials in a single-phase structure. Assuming that the material did not undergo
phase transition，the specific heat capacity and temperature should meet the formula
in the whole temperature range. The temperature points of In718plus alloy without
phase transformation were 100，200，300，400，500 and 1000 ℃，and the corresponding specific
heat capacity and temperature should meet the above functional relationship. In the
case of first-order polynomial fitting，all the other points except the data points
at 300 ℃ were distributed on both sides of the line，and the correlation coefficient
R2 at this time was 97.5%，with average effect. When quadratic polynomial fitting was
used，all the data points were closer to the fitting curve，the fitting effect was better，and
the correlation coefficient reached 99.7%. When the third and fourth order polynomials
were used，the centers of all data points fell on the fitting curve，and the correlation
coefficient was 100%，so the fitting effect was the best. It could be seen that the
specific heat capacity of In718plus met the third-order polynomial relationship with
temperature. The sensible specific heat capacity of the material was obtained by fitting
the data of the temperature range of the phase transition with polynomial fitting.
By comparing the correlation coefficient R2，it was found that the R2 reached 100% when the fitting reached the cubic polynomial.
Show more
Given the challenges posed by the low hardness and inadequate wear resistance of Ti-6Al-4V
alloy, this research aimed to explore an innovative solution by employing the laser
cladding technique to develop high-entropy alloy（HEA）coatings composed of TiZrNbCrCo
on the alloy's surface. The primary objectives were to investigate the effects of
varying the number of cladding layers on the elemental composition and to assess how
these variations influenced the phase constitution, microstructure, microhardness,
wear, and electrochemical properties of HEA coatings. To predict the phase composition
of the solid solution phases in HEA coatings with different layer numbers, empirical
thermophysical parameters were utilized. The methodology encompassed a detailed experimental
setup where the laser cladding process was meticulously optimized to fabricate coatings
with varying numbers of layers. This approach enabled the controlled manipulation
of the dilution rate and elemental distribution within the coatings, thereby allowing
for a comprehensive analysis of the resulting phase and microstructural characteristics.
The coatings were systematically analyzed using X-ray diffraction（XRD）to identify
their phase compositions and scanning electron microscopy to elucidate their microstructures.
Microhardness measurements were conducted to evaluate the mechanical enhancements,
while wear tests were performed to assess the wear resistance of the coatings. Furthermore,
electrochemical tests in a 3.5%NaCl solution were carried out to determine the coatings'
corrosion resistance. The results revealed that all coatings, exhibited a consistent
phase composition, predominantly featuring a body-centered cubic （bcc） structured
solid solution phase. This phase was characterized by dendrites rich in Nb and inter-dendrites
rich in Co. It was observed that an increase in the number of cladding layers led
to a decrease in the dilution rate, which in turn facilitated the formation of petal-like
Laves phases enriched in Co and Zr, along with α-Ti precipitates enriched in Zr. Remarkably,
the average microhardness of the coatings reached HV0.1747.7, approximately 2.33 times that of the substrate. This significant enhancement
in microhardness translated to a reduction in wear volume by 68.6% compared to the
substrate. The optimal corrosion resistance was achieved with a two-layer configuration,
which exhibited the lowest self-corrosion current （6.46×10−6 A·cm−2） a larger self-corrosion potential （-0.286 V）, and the lowest corrosion rate, indicating
a substantial improvement in corrosion resistance. The conclusion drawn from this
study highlighted the critical role of laser cladding parameters in influencing the
microstructural and compositional characteristics of HEA coatings. The enhancement
in mechanical and chemical properties could be attributed to the strategic manipulation
of the number of cladding layers, which optimized the microstructural features such
as the distribution of Laves phases and α-Ti precipitates. Moreover, this research
contributed to the broader academic discourse by elucidating the relationship between
laser cladding parameters, microstructural evolution, and the resulting properties
of HEA coatings. In summary, this comprehensive investigation into the development
and characterization of TiZrNbCrCo high-entropy alloy coatings on Ti-6Al-4V alloy
surfaces provided a promising approach for addressing the limitations of conventional
titanium alloys. The research outcomes not only demonstrated the feasibility of significantly
enhancing the hardness, wear, and corrosion resistance of Ti-6Al-4V alloys through
laser cladded HEA coatings but also opened up opportunities for using high-entropy
alloys in surface engineering to meet the needs of modern industries.
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Silicon(Si)-based anodes are widely recognized as the most promising alternatives
to conventional graphite anodes for lithium-ion batteries(LIBs), owing to their ultrahigh
theoretical specific capacity(4200 mAh·g-1), lowlithiation potential, abundant crustal reserves, low toxicity, and cost-effectiveness.
However, their large-scale commercialization is severely hindered by two intrinsic
challenges：1) drastic volume expansion(>300%)during lithiation/delithiation, which
induces particle pulverization, electrode integrity degradation, and continuous rupture/reformation
of the solid electrolyte interphase(SEI)films, thereby causing irreversible lithium-ion
consumption； 2) extremely low intrinsic electrical conductivity(1×10-4 S·cm-1), which restricts ion/electron transport kinetics and thus degrades rate capability.To
address these issues, early research efforts focused on nano-engineering of Si and
the development of Si-based composites. Nanostructured Si can partially alleviate
mechanical fracture by accommodating strain through size-dependent deformation mechanisms；
however, it tends to agglomerate during prolonged cycling and exhibits excessive side
reactions with the electrolyte, reducing the initial Coulombic efficiency(ICE)and
cycling lifespan. Si/carbon(Si/C)composites design, which take advantage of the high
electrical conductivity, chemical stability, and mechanical flexibility of carbon
matrices, have emerged as a primary route toward commercialization. Nevertheless,
challenges related to the inherently low conductivity of Si and inadequate interfacial
bonding between Si and carbon remain unresolved. Against this backdrop, this review
emphasized doping modification as a fundamental strategy to enhance the electrochemical
performance of Si-based anodes. Starting from the lithium storage mechanism of Si—which
stored lithium via an alloying/dealloying reaction to form various Li-Si alloys, with
a theoretical maximum lithiation phase of Li22Si5 accommodating 4.4 Li atoms per Si atom—and its core limitations, we systematically
analyzed the regulation mechanisms and functional effects of different doping approaches.
These were categorized into three types：non-metallic (heteroatom) doping, metallic
doping, and multi-element co-doping. Non-metallic doping(e.g., with B, P, N, or S)effectively
modulated the electronic structure of Si-based materials, improved Li+ transport pathways, enhanced electronic conductivity, and promoted the formation
of a more stable SEI layer. Metallic doping was subdivided into two categories：electrochemically
inactive metals(e.g., Fe, Ti), which enhanced electrical conduction and provided mechanical
reinforcement to alleviate volume expansion, and electrochemically active metals(e.g.,
Mg, Ge), which contributed additional capacity and helped accommodate volume expansion
through synergistic alloying behavior. Multi-element co-doping(including non-metal/non-metal
and metal/non-metal combinations)achieved synergistic optimization of multiple physicochemical
properties, thus further enhancing conductivity, structural stability, and fast-charging
performance. Finally, this review outlined future perspectives for doping modification
technologies in Si-based anodes, including the exploration of novel co-doping systems
to simultaneously address conductivity, volume expansion, and SEI stability； the optimization
of doping processes for precise control over elemental distribution and concentration；
and the integration of in-situ characterization techniques to deepen the understanding
of the influence of doping elements on the lithium storage mechanism. This review
aimed to provide fundamental theoretical insights and practical technical guidance
for the development of high-energy-density and fast-charging Si-based anode materials,
thereby accelerating their commercial adoption.
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