Microstructure and mechanical properties of directed energy deposited 316L/Ti6Al4V functionally graded materials via constant/gradient power

In this paper, two types of 316L/Ti6Al4V functionally graded materials (FGMs) were manufactured by directed energy deposition (DED) using different sets of laser power (constant/gradient). The microstructure and microhardness in each layer, as well as the tensile properties of both types of specimens were investigated. Results showed the tensile strength of FGM deposited by gradient power was higher because of its smaller grains, as well as fewer and smaller FeTi-based multicomponent composite intermetallic compounds: (M1-xFex)Ti (M = Ni and Cr, 0.38 < x < 0.69). Besides, microhardness gradually increased with the increasing content of 316L powder for both types of specimens. Furthermore, the mechanisms illustrating the effects of microstructure, namely phases and grains, on tensile properties of two types of FGMs deposited by constant/gradient laser power were revealed.