Ti8LC钛合金热处理工艺对硬度和组织的影响

Effect of Heat Treatment on Hardness and Microstructure of Ti8LC Alloy

钛合金Ti8LC是一种新型低成本近α型的钛合金,为了研究该合金热处理对其组织结构的影响规律,对其进行不同温度固溶处理,随后在不同温度进行时效热处理。用金相显微镜和扫描电镜观察了不同热处理工艺下的微观组织形貌,并通过能谱分析了不同工艺下元素的含量变化。采用洛氏硬度计测试了试样的平均硬度,分析了固溶温度和时效温度对其微观组织形态的变化影响,以及硬度大小、微观组织结构中相的形态和组织组成的相关性。结果表明:固溶处理温度对Ti8LC固溶后的显微组织及随后的时效组织都有极大的影响,随固溶温度的升高,由片状逐渐转为块状。经相同时效工艺处理的合金其显微组织受固溶后组织的遗传影响,合金的硬度随着固溶温度的升高,先降低后升高;通过微观组织和硬度的良好配合,可以确定Ti8LC合金固溶时效的最佳工艺。

Ti8LC alloy is a new type of near-α-Ti alloy with low cost.In order to get the effect of heat treatment on microstructure,solution treatment was performed at different temperature,then aging treated at various temperatures.Microstructure of Ti8LC alloy in different heat treatment was examined using optical microscope and SEM.The compositions of Ti8LC alloy in different process were analyzed by EDX.Hardness was measured also.The effects of solution temperature and aging temperature on microstructure of the alloy were discussed.It was found that the hardness was related with the phase constitution and microstructure.The results showed that the temperature of solution treatment had a great effect on the microstructure of Ti8LC after the solution and subsequent aging treatment.With the increase of solution temperature,the microstructure of Ti8LC transformed from plate into lump.The grain size of alloy varied with aging treatment inherited the microstructure of solution.The hardness of alloy decreased with the increasing temperature at first,then increased with the increasing temperature.Considering the microstructure and the hardness,the optimal process parameters of solution-aging treatment of Ti8LC could be acquired.