Effects of Heat Treatment on Low Cycle Fatigue Properties of Selective Laser Melting Ti-6Al-4V Alloy
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 βcolumnar 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.