Influence mechanism of microstructure variation on mechanical properties of laser melting deposition Ti-6Al-4V alloy under electroshocking treatment

In this work, the electroshocking treatment (EST) was applied on the Ti-6Al-4V alloys prepared by laser melting deposition (LMD), and the evolutions of microstructure and mechanical property were investigated. The results indicated that the size of columnar grains in LMD Ti-6Al-4V was reduced after EST, and the α refinement was obvious. The basketweave microstructure existed due to the effect of EST. The results of electron backscatter diffraction (EBSD) showed that EST could reduce the orientation concentration and weaken the texture. The texture in Ti-6Al-4V was formed during LMD, and it became uniform and weak after EST. On the mechanical properties, the microhardness of specimen increased after EST with 0.04 s, and the yield strength changed little and the strain increased more obviously because of the microregion phase transition. The compression fracture morphology revealed that the fracture mode of LMD Ti-6Al-4V changed from the brittle fracture to ductile fracture because of the microstructure variation. Based on above results, it demonstrates that EST is a new exploration method to manipulate the microstructure of LMD titanium alloys and modify the comprehensive mechanical properties of LMD titanium alloys.