Structure and Mechanical Properties of TiB₂+Si/TA19 Composites AITranslate

［1］Cao Z，Wang X D，Li J L，Wu Y，Zhang H P，Guo J Q，Wang S Q. Reinforcement with graphene nanoflakes in titanium matrix composites ［J］. Journal of Alloys and Compounds，2017，696：498.

［2］（任嘉腾，李鹏远，冯雪艳，徐俊杰. （Ti，Zr）5Si3/TA19（C，N）复合材料组织与力学性能研究 ［J］. 铜业工程，2025，（1）：112.）

J T Ren，P Y Li，X Y Feng，J J Xu. Microstructure and mechanical properties of （Ti，Zr）5Si3/TA19（C，N）composites ［J］. Copper Engineering，2025，（1）：112.

［3］（李冬，曾卫东，李欣，高雄雄，徐建伟. Ti60合金保温过程中片状组织的粗化行为 ［J］. 稀有金属，2022，46（3）：273.）

D Li，W D Zeng，X Li，X X Gao，J W Xu. Roughening behavior of sheet tissue during Ti60 alloy heat preservation ［J］. Chinese Journal of Rare Metals，2022，46（3）：273.

［4］Huang L J，Geng L，Li A B，Yang F Y，Peng H X. In-situ TiBw/Ti6Al4V compositeswith novel reinforcement architecture fabricated by reaction hot pressing ［J］. Scripta Materialia，2009，60：996.

［5］（刘玉川，殷录成，陈攀，熊馨. 某金矿石工艺矿物学研究 ［J］. 黄金，2023，44（1）：63.）

Y C Liu，L C Yin，P Chen，X Xiong. A study on the process mineralogy of a certain gold ore ［J］. Gold，2023，44（1）：63.

［6］Jiao Y，Huang L J，Wang S，Li X T，An Q，Cui X P，Geng L. Effects of first-scaleTiBw on secondary-scale Ti5Si3 characteristics and mechanical properties of in-situ （Ti5Si3+TiBw）/Ti6Al4V composites ［J］. Journal of Alloys and Compounds，2017，704：269.

［7］（韩秀峰，王伦，朱明亮，廖仲祥，张露. TA19钛合金电子束焊接头微观组织与性能研究 ［J］. 稀有金属，2021，45（7）：778.）

X F Han，L Wang，M L Zhu，Z X Liao，L Zhang. Study on microstructure and properties of TA19 titanium alloy electron beam welding joint ［J］. Chinese Journal of Rare Metals，2021，45（7）：778.

［8］Wang S，An Q，Zhang R，Jiang S，Huang L J，Chen R，Liu B X，Jiao Y，Geng L. Microstructure characteristics and enhanced properties of network-structured TiB/（TA15-Si）composites via rolling deformation at different temperatures ［J］. Materials Science and Engineering：A，2022，829：142176.

［9］（卢思瑶，马凤仓，刘平，李伟，刘新宽. 热加工对TiB增强钛基复合材料显微组织和力学性能的影响 ［J］. 稀有金属，2018，42（4）：379.）

S Y Lu，F C Ma，P Liu，W Li，X K Liu. Effects of hot working on microstructure and mechanical properties of TiB-reinforced titanium matrix composites ［J］. Chinese Journal of Rare Metals，2018，42（4）：379.

［10］（任嘉腾，李鹏远，徐俊杰. TiBw/TA19（Si，N）复合材料组织与力学性能研究 ［J］. 铜业工程，2024，（5）：122.）

J T Ren，P Y Li，J J Xu. Microstructure and mechanical properties of TiBw/TA19（Si，N）composites ［J］. Copper Engineering，2024，（5）：122.

［11］Huang L J，Geng L，Peng H X，Kaveendran B. High temperature tensile properties of in situ TiBw/Ti6Al4V composites with a novel network reinforcement architecture ［J］. Materials Science and Engineering：A，2012，534：688.

［12］Sun F B，Huang L J，Zhang R，Wang S，Jiang S，Sun Y，An Q，Jia Y，Geng L. In-situ synthesis and superhigh modulus of network structured TiC/Ti composites based on diamond-Ti system ［J］. Journal of Alloys and Compounds，2020，834：155248.

［13］（王幸运，杨铮，赵小龙. 不同热处理制度对Gr.38钛合金板材的组织性能的影响 ［J］. 锻压技术，2024，49（3）：202.）

X Y Wang，Z Yang，X L Zhao. Influence of different heat treatment systems on microstructure and properties of Gr.38 titanium alloy plate ［J］. Forging & Stamping Technology，2024，49（3）：202.

［14］（林有智，廖萍，陈剑虹. 钛铝合金原位拉伸损伤与断裂过程 ［J］. 有色金属工程，2022，12（8）：24.）

Y Z Lin，P Liao，J H Chen. Insitu tensile damage and fracture process of titanium aluminum alloy ［J］. Nonferrous Metals Engineering，2022，12（8）：24.

［15］Jiao Y，Huang L J，Geng L，Zhang R，Jiang S，Li X T，Gao Y N. Strengthening and plasticity improvement mechanisms of titanium matrix composites with two-scale network microstructure ［J］. Powder Technology，2019，356：980.

［16］（董显娟，张殿，王宇航，吴轩轩，涂泽立，魏科，黄龙，徐勇. 热变形参数对TB15钛合金动态再结晶行为的影响 ［J］. 塑性工程学报，2024，31（1）：50.）

X J Dong，D Zhang，Y H Wang，X X Wu，Z L Tu，K Wei，L Huang，Y Xu. Influence of thermal deformation parameters on the dynamic recrystallisation behaviour of TB15 titanium alloy ［J］. Journal of Plasticity Engineering，2024，31（1）：50.

［17］Wang S，Huang L J，Jiang S，Zhang R，Liu B X，Sun F B，An Q，Jiao Y，Geng L. Microstructure evolution and tensile properties of as-rolled TiB/TA15 compo-sites with network microstructure ［J］. Materials Science and Engineering：A，2021，804：140783.

［18］（王伟，韩子茹，王庆娟，周海雄，高原，王快社. TiB2增强Ti2AlNb基复合材料的放电等离子烧结制备及其摩擦学性能研究 ［J］. 稀有金属，2020，44（12）：1255.）

W Wang，Z R Han，Q J Wang，H X Zhou，Y Gao，K S Wang. Preparation and tribological properties of TiB2 reinforced Ti2AlNb matrix composites by spark plasma sintering ［J］. Chinese Journal of Rare Metals，2020，44（12）：1255.

［19］Morsi K. Review：titanium-titanium boride composites ［J］. Journal of Materials Science，2019，54（9）：6753.

［20］（王亚辉，黄亮，刘翔，李建军. 基于增材制造和锻造复合成形的TC4钛合金组织和性能研究 ［J］. 稀有金属，2021，45（8）：897.）

Y H Wang，L Huang，X Liu，J J Li. Microstructure and properties of TC4 titanium alloy based on additive manufacturing and forging composite forming ［J］. Chinese Journal of Rare Metals，2021，45（8）：897.

［21］（李娟，蔡建明，段锐. 近α型TG6高温钛合金中硅化物的沉淀析出行为 ［J］. 航空材料学报，2012，32（5）：32.）

J Li，J M Cai，R Duan. Precipitation behavior of silicides in near-αTG6 high-temperature titanium alloy ［J］. Journal of Aeronautical Materials，2012，32（5）：32.

［22］（刘晓燕，柳奎君，杨西荣，王敬忠，罗雷. 超细晶纯钛疲劳裂纹扩展及裂纹尖端组织演变 ［J］. 稀有金属，2022，46（7）：882.）

X Y Liu，K J Liu，X R Yang，J Z Wang，L Luo. Fatigue crack propagation and crack tip microstructure evolution of ultrafine crystalline pure titanium ［J］. Chinese Journal of Rare Metals，2022，46（7）：882.

［23］Jiao X Y，Du D D，Chen W Z，Zhang W C，Yang J L，Cui G R. Effect of heat treatment on microstructure evolution and mechanical properties of 2.5 vol% TiBw/TA15 composites with different deformation statuses ［J］. Advanced Engineering Materials，2018，20（10）：1800190.

［24］Jiao Y，Huang L J，An Q，Jiang S，Gao Y N，Cui X P，Geng L. Effects of Ti5Si3 characteristics adjustment on microstructure and tensile properties of in-situ （Ti5Si3+TiBw）/Ti6Al4V composites with two-scale network architecture ［J］. Materials Science and Engineering：A，2016，673：595.

Basic Information:

DOI：10.13373/j.cnki.cjrm.XY23090004

Chinese Library Classification Number:TB333

Citation Information:

With the rapid development of aerospace field，traditional titanium alloys can no longer meet the requirements. Improving strength while maintaining plasticity has become an important direction in this field，and titanium matrix composites （TMCs）can achieve good strength-plasticity matching through composition modulation. The addition of reinforcing phase can be categorized into direct addition and in-situ autogenous. In-situ autogenous has better interfacial bonding，better compatibility，and more thermodynamic stability than direct addition. Compared with the continuously reinforced TMCs，the discontinuously reinforced TMCs have the advantages of low preparation cost，easy processing，better performance，and isotropy. （Ti，Zr）₅Si₃ and TiB_w whiskers are generated by the in-situ autogenous reaction between Si and TiB₂ reinforcing materials and the matrix，are thermodynamically stable. They exhibit similar density and thermal expansion coefficients to those of the matrix，making themeffective reinforcing materials for titanium alloys. TA19 titanium alloy has the advantages of high strength，good toughness，and good creep resistance at high temperature. Therefore，in this study，TiB₂+Si/TA19 composite blocks were prepared by adjusting the compositions and utilizing low-energy mechanical ball milling and spark plasma sintering （SPS）techniques. SPS process featured a fast heating rate and short holding time，which could refine the grain size and result indense and uniform sintered material. Composites were prepared by a （1+6）h two-step ball milling method. The sintering temperature was 1000 ℃，with a holding time of 10 min and a sintering pressure of 40 MPa. Cylindrical blocks with a diameter of 50 mm and a thickness of 15 mm were prepared. X-ray diffraction （XRD）and metallographic specimens were cut off from the sintered cylindrical blocks using wire cutting. The room temperature tensile properties were tested using an electronic universal testing machine （model UTM5105X）at tensile rate of 1 mm·min⁻¹，with an extensometer having a gauge length of 12.5 mm. The microstructure and fracture morphology of TiB₂+Si/TA19 composites were characterized and analyzed using optical microscope （model AxioVertA1）and scanning electron microscope （model EM30AX+）. The effects of different contents of Si and TiB₂ reinforcing phases on the microstructure and mechanical properties of TA19 titanium alloy were investigated，and the optimal ratio of Si and TiB₂ reinforcing phases was determined. The results showed that when Si was added alone，β-phase was refined，α-sheet layer spacing increased. A large amount of Si dissolved into the matrix as solid-solution strengthening during sintering，while a small amount of Si precipitated out in the form of fine，diffusely distributed silica （Ti，Zr）₅Si₃ when the temperature was lower than that of α/β-phase interface in the temperature reduction process. Strengthening mechanisms included solid solution strengthening and diffusion strengthening. Continued addition of TiB₂ introduced TiB_w whiskers，which were distributed at grain boundaries and provide nucleation sites for Si，resulting in a secondary quasi-reticulation and significant grain refinement. The main strengthening mechanisms were dislocation strengthening，fine grain strengthening，and solid solution strengthening. The addition of 0.3% Si to the composites resulted in a good match of strength and plasticity，and the tensile strength of Si/TA19 composites reached 1181.1 MPa with an elongation up to 16.4%，and the fracture of 0.3%Si/TA19 composites was characterized by a plastic fracture with a typical concave morphology. With the addition of 0.5% TiB₂ on top of 0.3% Si，the tensile strength of TiB₂+Si/TA19 composites reached 1270.1 MPa and the elongation remained at 10.2%. This was attributed to the in-situ generated TiB_w whiskers distributed along the original β grain boundaries，which could effectively enhance the hindering effect of grain boundaries on the dislocation movement. The grain refinement led to an increase in the number of grain boundaries and an enhancement of the hindering effect，and at the same time，the connectivity of the plastic region inside the mesh structure was well ensured，so the strength of the composite material was improved，and the plasticity was not reduced much. When the TiB₂ addition reached 0.7%，the strength was significantly increased to 1316.1 MPa，but the plasticity was significantly reduced to 2.5%. This was because the addition of too many whiskers greatly reduced the connectivity of the matrix，and the debonding of TiB_w with the matrix was also very unfavorable to the plasticity，so the fracture elongation was significantly reduced. With the increase of TiB₂ content on the basis of 0.3% Si，the reinforcing phases were enriched at grain boundaries and dislocation plugging occurs，which led to an increase in the number of microcracks and growth of aggregation during tensile process，resulting in a decrease in the plasticity of the material. The fracture mode of the composites gradually changed from plastic fracture to mixed fracture of plastic and brittle fracture.