热处理对选区激光熔化 Ti-6Al-4V 合金低周疲劳性能的影响

In order to improve the low cycle fatigue property of selective laser melting Ti-6Al-4V alloy, the effects of heat treatment on the microstructure and properties of selective laser melting Ti-6Al-4V alloy were studied by OM, SEM, TEM, room temperature tensile and low cycle fatigue tests. The results show that the as-built microstructure is characterized by epitaxially grown β columnar grains and acicular martensite α′ with a certain orientation in the grains. After annealing, α′ decomposes and is transformed into basket-weave α+β. After cyclic heat treatment, lath α becomes globularized, and the microstructure is composed of equiaxed α, lath α and residual β. After heat treatment, the low cycle fatigue property of the annealed alloy reaches more than 87% of that of the forgings. Besides, the property of cyclic heat treated alloy reaches more than 90% of that of the forgings.