固溶处理对TC4合金组织和硬度的影响

对TC4合金进行不同固溶处理,研究了固溶温度、保温时间、冷却方式对合金显微组织和硬度的影响。结果表明,随着固溶温度的升高,TC4合金由等轴组织到双态组织再到全马氏体组织转变,硬度逐渐增加;达到高温平衡状态时,延长保温时间对TC4合金显微组织和硬度的影响不明显;当固溶温度分别为925 ℃和975 ℃时,随着冷却速率的降低,α相在冷却过程中发生扩散长大,β转变组织从α'马氏体变为次生α相+β相的片层组织,硬度分别从水冷条件下的359~389 HV0.2降为空冷条件下的318~327 HV0.2;炉冷后得到全等轴组织,硬度较低,约300 HV0.2。

Effect of solution treatment on microstructure and hardness of TC4 alloy

TC4 alloy was subjected to different solution treatments, and effects of solution temperature, holding time and cooling method on microstructure and hardness of the alloy were studied. The results show that with the increase of solution temperature, microstructure of the TC4 alloy transforms from equiaxed structure to dual-state structure to full martensite structure, and the hardness gradually increases. When the high temperature equilibrium state is reached, the extension of holding time has little effect on microstructure and hardness of the TC4 alloy. When the solution temperature is 925 ℃ and 975 ℃, respectively, as the cooling rate decreases, the α phase diffuses and grows during the cooling process. The β transformation structure changes from α' martensite to secondary α+β lamella structure, and the hardness respectively reduces from 359-389 HV0.2 under water-cooling condition to 318-327 HV0.2 under air-cooling condition. After furnace cooling, a fully equiaxed structure is obtained, the hardness is lower, about 300 HV0.2.