原位自生TiB2/Al-4.5Cu复合材料微观组织和力学性能  

Microstructure and mechanical properties of in-situ synthesized TiB2/Al-4.5Cu composites

作　　者：薛彦庆 郝启堂[1] 魏典 李博 XUE Yan-qing;HAO Qi-tang;WEI Dian;LI Bo(State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《材料工程》2021年第2期97-104,共8页Journal of Materials Engineering

基　　金：国家自然科学基金(51375391);陕西省重点研发计划(2020GY-117);西北工业大学凝固技术国家重点实验室自主研究课题资助项目(2019-TZ-03)。

摘　　要：采用混合盐反应法制备TiB2含量分别为0%,2%,5%,8%(质量分数,下同)的TiB2/Al-4.5Cu复合材料,T6热处理后,采用XRD,ICP,OM,SEM,EDS等测试手段和室温拉伸实验进行微观组织观察和力学性能测试。XRD和ICP测试证实,合金体系中仅含α-Al,Al2Cu及TiB2,无Al3Ti,Al2B等反应中间产物。OM和SEM发现,基体材料中α-Al平均晶粒尺寸为167.5μm,而在2%,5%,8%的TiB2/Al-4.5Cu中,其平均晶粒尺寸依次为110.4,87.2,75.2μm,晶粒细化效果显著。TEM观察发现,TiB2颗粒主要分布在晶界处,呈四方和六方结构。室温拉伸实验表明,随着TiB2含量的增加,强度、显微硬度值均呈增加趋势,但伸长率不断下降。当加入8%TiB2时,屈服强度、抗拉强度、弹性模量和显微硬度分别达到356 MPa,416 MPa,92.5GPa和96.5HV,但其伸长率从10.3%降低到4.3%。载荷传递强化、细晶强化、位错增殖强化是TiB2/Al-4.5Cu复合材料力学性能得以大幅提升的影响因素,尤其是在位错增殖强化作用下,TiB2颗粒周边致密分布的位错胞、位错环对强度的提升起到了决定性作用。Various contents(0%,2%,5%and 8%,mass fraction,the same below)of TiB2/Al-4.5 Cu composites were prepared by mixed salt reaction method.After T6 heat treatment,XRD,ICP,OM,SEM,EDS and tensile test at room temperature were adopted to observe microstructure and assess mechanical properties of the composites.XRD and ICP tests confirm that the alloys contained onlyα-Al,Al2 Cu and TiB2,Al3Ti and Al2B phases are not found.OM and SEM observations show that the average grain size ofα-Al in the matrix material is 167.5μm,while is 110.4,87.2,75.2μm in 2%,5%,and 8%TiB2/Al-4.5 Cu,respectively.TEM observation indicates that the TiB2 particles are quadrate and hexagonal structure dispersed in the grain boundary chiefly.Room-temperature tensile experiments show that with the increasing of TiB2 content,the mechanical properties of TiB2/Al-4.5 Cu composites are improved gradually.Especially,for the composite with TiB2 mass fraction of8%,the yield strength(YS),ultimate tensile strength(UTS),elastic modulus and microhardness are356 MPa,416 MPa,92.5 GPa and 96.5 HV,separately.However,the elongation(δ)decreases from10.3%to 4.3%.Analysis suggests the enhancement of load transfer,fine crystal and dislocation proliferation are all the factors that greatly improve the mechanical properties of TiB2/Al-4.5 Cu composites,in especial,the dislocation cell and loop distributed around TiB2 particles play a decisive role in enhancing the strength.

关 键 词：铝基复合材料 热处理 微观组织 力学性能 位错 

分 类 号：TG146.21[金属学及工艺—金属材料]