固溶时效热处理对激光增材制造TC17钛合金组织与性能的影响

Effect of Solution Aging Heat Treatment on Microstructure and Mechanical Properties of Laser Additive TC17 Titanium Alloy

采用激光增材制造技术制备TC17钛合金试样,研究不同固溶时效温度热处理对激光增材制造TC17钛合金显微组织、硬度及摩擦磨损性能的影响规律。研究表明,经固溶时效处理后,显微组织转变为粗大的网篮组织,随着固溶温度升高,初生α相(αp)逐渐粗化且体积分数下降,经时效后从β转变组织析出次生α相(αs)的体积分数有所增加,当固溶温度进一步升高接近相变点,α相发生溶解现象;随着时效温度升高,次生α相片层厚度明显增加。经固溶时效热处理后显微硬度显著提升,其中在840℃/1 h, AC+800℃/4 h, WQ+630℃/8 h, AC固溶时效处理后,显微硬度最高为447.6 HV,与沉积态相比提高14%,且高于锻件标准(400 HV),平均摩擦系数最低为0.21,与沉积态相比降低34%,磨损量最少为3.4 mg,约为沉积态磨损量(9.7 mg)的1/3,表现出较好的抗磨性能。

TC17titanium alloy samples were prepared by laser additive manufacturing technology.The effects of different solution aging temperature and heat treatment on microstructure,microhardness and tribological properties of TC17 titanium alloy were studied.The results show that the microstructure is transformed into coarse basket microstructure after solution aging treatment.With the increase of solution temperature,the primaryαphase(αp)coarses gradually and the volume fraction decreases.After aging,the volume fraction of secondaryαphase(αs)precipitates from the β transition microstructure.With the aging temperature increasing,the thickness of the secondaryαphotographic layer increases obviously.After solid solution aging heat treatment,the microhardness increased obviously.After 840℃/1h,AC+800℃/4h,WQ+630℃/8h,AC solution aging treatment,the microhardness reached the highest 447.6HV,14%higher than that of deposition,and higher than the forging standard(400HV).The lowest average friction coefficient is 0.21,which is 34% lower than that of the deposition,and the wear amount is 3.4mg at least,which is about 1/3of that of the deposition(9.7mg),showing good anti-wear performance.