热处理对激光立体成形TA15合金组织及力学性能的影响

Effects of Heat Treatment on the Microstructures and Mechanical Properties of TAl5 Titanium Alloys by Laser Solid Forming

摘要:

研究了激光立体成形TA15钛合金沉积态、退火态、固溶时效态以及双固溶时效态4种状态的组织及力学性能。结果表明：沉积态组织为大量不同取向相互交叉的发达魏氏α+β板条，其拉伸性能表现出一定的各向异性。经退火后，显微组织没有明显变化，塑性在强度降低不多的情况下得到了提高。退火态试样具有良好的综合拉伸性能，达到了锻件退火态的拉伸性能标准。经固溶时效处理后可得到粗化的α初+α'组织，成形件的强度显著提高。经双固溶时效后可得到粗化α初+细化α次+α'组织，强度稍有降低。与室温相比，4种状态均呈现出高温强度降低而塑性提高的特点。对于不同的热处理状态，成形试样的洛氏硬度HRC处于30~45范围变化，不同热处理态的硬度变化与拉伸性能中的强度变化趋势一致

Abstract:

The effects of heat treatment on the microstructures and mechanical properties of TAl5 titanium alloys fabricated by laser solid forming (LSF) were investigated. The microstructure of the as-deposited sample is composed of Widmanst?tten α+β laths of different orientations, and there is certain anisotropy in the tensile properties of LSFed samples. There is no obvious change in the microstructure by annealing treatment, but the plasticity of LSFed samples is increased obviously accompanied with a little decrease of the tensile strength. The annealed sample presents good comprehensive tensile properties, which can satisfy the tensile properties standard of annealed TA15 wrought. After solution-aging treatment, the microstructure consists of coarse primary α and α', and the strength of LSFed samples is significantly improved. The microstructure of coarse primary α, refined secondary α and α' can be obtained by double solution-aging treatment, which results in a slight decrease in the tensile strength. Compared with room temperature tensile properties, all of LSFed sample in the four kinds of treatment states show a lower strength and a higher plasticity at high temperature. The hardness of LSFed samples is ranged from 30 HRC to 45 HRC for the different heat treatments, and the change trend of hardness after different heat treatments is in agreement with that of tensile strength.