退火温度对TC6合金微观组织和力学性能的影响

Influence of annealing temperature on microstructure and mechanical properties of TC6 alloy

研究了在普通退火和等温退火时,不同退火温度下TC6合金的微观组织演变过程及力学性能变化规律。结果表明:普通退火中随退火温度的升高,微观组织中细小的次生α相逐渐溶入基体相而消失,粗大的次生α相继续长大;最后发生再结晶,形成新的β晶粒在其内部析出新的针状组织。这一过程中合金室温强度呈抛物线形变化,并在850℃和870℃附近达到最大值约1090 MPa。等温退火中随退火温度的升高,微观组织中次生α相发生等轴化,由片层组织长大为等轴α相;并随退火温度的升高,等轴α相尺寸显著增加。这一过程中合金室温强度呈台阶式降低,当温度在850℃和870℃时,室温强度达到最大值约1000 MPa。

The microstructure evolution and tensile properties of TC6 alloy were studied at different annealing temperature in heat treatment.The experimental results show that,with the increasing of common annealing temperature,small secondary α phase dissolves into the matrix gradually and disappears,coarse secondary α phase continues to grow and recrystallize. In this process,the strength of the alloy at room temperature shows a parabolic shape,and reaches the maximum value of 1090 MPa nearby 850 ℃ and 870 ℃. With the increasing of isothermal annealing temperature,the secondary α phase transforms into equiaxed α phase and grows up gradually. In this process,the strength of the alloy at room temperature reduces in the form of steps,and reaches the maximum value of 1000 MPa nearby 850 ℃ and 870 ℃.