Microstructures and mechanical properties of laser melting deposited Ti6Al4V/316L functional gradient materials

Abstract Functional gradient material (FGM) is an innovative material possessing gradient properties using different premixed proportions of two or multiple metallic powders. In the present work, novel FGMs of Ti6Al4V/316L composites with different premixed proportions were successfully fabricated by laser melting deposition (LMD). The microstructure and phase evolution were characterized by means of optical microscopy (OM), X-ray diffractometer (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Subsequently, the effects of different Ti6Al4V/316L proportions on micro-hardness, tensile and wear properties were systematically investigated. The results showed that the grain refinement process had experienced three following stages of cellular crystal, columnar crystal and equiaxed crystal with increasing the 316L content. Finally, the LMD-processed FGM specimen with a premixed proportion, 85 wt. % Ti6Al4V/15 wt. % 316L, is achieved, and exhibits the optimal wear resistance.