近日,中国有色金属工业科学技术奖获奖项目正式揭晓。长沙有色冶金设计研究院有限公司(简称长沙有色院)凭借在有色金属工业领域的持续深耕与创新突破,共有9项科技成果荣登榜单,涵盖一等奖4项(牵头1项、参与3项)、二等奖4项(牵头4项)、三等奖1项(参与1项),彰显了该公司在行业技术创新与工程化应用方面的雄厚实力与领先地位。

《稀有金属与硬质合金》创刊于1973年,是中文核心期刊,致力于稀有金属冶金与材料领域的科研创新与产业应用。本刊坚持“传播先进科技成果,引领创新,贴近科研与生产”的办刊宗旨,为科研人员及工程技术人员提供高水平的学术交流平台。为提升学术成果传播效率,缩短出版周期,本刊已于2025年7月1日起正式开通中国知网(CNKI)网络首发服务,录用定稿将优先在线发布,与印刷版具有同等学术效力。

《稀有金属与硬质合金》由长沙有色冶金设计研究院有限公司和中国有色金属学会联合主办,长沙有色冶金设计研究院有限公司负责编辑出版,为2023版北大中文核心期刊、中国科学引文数据库来源期刊,入编《中国学术期刊(光盘版)》和《中国科技期刊数据库》等数字化网络。

The use of transition metals as sintering aids is an effective method to improve the properties of W-Cu composites.In this study,Fe-coated W powder was synthesized using a liquid-phase addition method combined with hydrogen reduction method,and then W-Cu composites were prepared through planetary ball milling and liquid-phase sintering.The effects of sintering temperature and Fe content on the microstructure and physical and mechanical properties of W-Cu composites were examined,employing techniques such as SEM,EDS,XRD,Vickers hardness tester,electronic densimeter,and conductivity meter.The experimental results indicate that increasing the sintering temperature can improve the homogeneity of the W and Cu phases in the W-Cu composites,leading to a substantial enhancement of material properties.At a sintering temperature of 1400℃,the W-Cu composite exhibits optimal physical and mechanical properties,although this is accompanied by significant Cu volatilization.Under the activated sintering condition of 1300℃,the increase in Fe content leads to the increase in hardness and relative density of the W-Cu composites.When the Fe content is 1.2%,the hardness and relative density reach 239 HV and 99.1%,respectively.Conductivity initially increases but subsequently decreases,reaching an optimal value of 41.4%IACS when the Fe content is 0.6%.Therefore,the addition of Fe facilitates the liquid-phase sintering densification of W-Cu composites,resulting in significant improvements in their microstructure and physical and mechanical properties.However,excessive Fe addition has an adverse impact on conductivity.In practical applications,the Fe content should be controlled at approximately 0.6%.

W-Cu composites have important applications in the fields of electronic packaging,nuclear energy industry and military aerospace due to the combination of tungsten's high hardness and high temperature resistance with copper's excellent thermal conductivity and electrical conductivity.However,the poor mutual solubility and wettability between W and Cu phases limit further comprehensive performance improvement of the material.In this paper,W-25Cu composites were prepared by a scalable pressureless infiltration process.Submicron WC phases were formed at the W/Cu interfaces by in-situ reaction using the high carbon residue characteristics of phenolic resin,and the microstructure and properties of WC reinforced W-25Cu composites were investigated.The results show that compared with low carbon residue binders such as stearic acid,paraffin and rubber solution,the addition of phenolic resin significantly enhances the relative density and hardness of W-25Cu composite,though it slightly reduces electrical conductivity.To a certain extent,increasing the infiltration temperature and prolonging the holding time can improve the properties of the material,but excessive temperature causes copper leakage on the surface of the material and impairs its performance.The comprehensive performance of W-25Cu composite is the best under the pressureless infiltration process of 1300℃ for 120 min,and the relative density,hardness and electrical conductivity reach 99%,243 HV and 46.7%IACS,respectively.

Molybdenum-rhenium alloy is regarded as an ideal core material for nuclear reactors due to its good compatibility with common nuclear fuels under high temperature conditions.However,the lack of high-temperature strength and room temperature toughness limits its application in extremely harsh environment.In this study,the strategy of layered Ti₃AlC₂ceramic phase strengthening molybdenum-rhenium alloy was put forward.Mo-5%Re and Mo-5%Re-1%Ti₃AlC₂alloys were prepared by powder metallurgy method.The effects of layered Ti₃AlC₂ceramic phase doping on the molybdenum-rhenium powder morphology and 1100~1400℃ hot compression properties and room-temperature mechanical properties of molybdenum-rhenium alloy were investigated.The results show that the Mo-5%Re-1%Ti₃AlC₂alloy exhibits an everage grain size of 21.6μm,with Ti₃AlC₂particles distrubuted both at grain boundaries and within the grains.During hot compression at 1100℃,the peak stress of the alloy reaches 285.7 MPa,which is 17.6% higher than that of Mo-5%Re alloy.After rolling and annealing at 1200℃,the tensile strength of the alloy at room temperature reaches 609 MPa,and the elongation after fracture reaches 22.5%,which increase by 19.88% and 85.95% compared with Mo-5%Re alloy,respectively.The introduction of layered Ti₃AlC₂ceramic phase can hinder dislocation movement to increase the dislocation density in molybdenum-rhenium alloy,hinder the grain boundary migration and inhibit dynamic recrystallization,thus improving the dynamic recrystallization temperature and high-temperature strength of molybdenumrhenium alloy.The unique layered structure of Ti₃AlC₂can reduce the local stress field of the crack tip through crack deflection and bridging,and improve the mechanical properties of molybdenum-rhenium alloy at room temperature.

Cu-25Cr-La alloy was prepared using powder metallurgy method,and the effects of rare earth La content on the conductivity and oxidation resistance of the alloy were investigated,as well as the microstructure and phase composition of the alloy oxide layer after La addition.The results indicate that as the La content increases,the conductivity of Cu-25Cr-La alloy gradually decreases while its oxidation resistance improves.When the mass fraction of La is 0.3%,the alloy exhibits optimal comprehensive performance.After oxidation at 800℃ for 10 h,the oxide layer of Cu-25Cr alloy exhibits cracks and spallation,whereas the oxide layer of Cu-25Cr-0.3La alloy remains relatively dense with minor cracks.The oxidation kinetic curve of the latter primarily follows a cubic law,and the oxide layer is mainly composed of CuO and Cr₂O₃.