Microstructure and Tensile Properties of TC17/TC11 Dual Alloy Fabricated with Laser Melting Deposition Method

The microstructure and tensile properties of TC17/TC11 dual alloy fabricated with direct laser melting deposition method by two connecting processes (direct connection and gradient connection) were investigated. The results show that the TC17/TC11 dual alloy can be divided into three parts: uniform TC17 zone, transition zone and uniform TC11 zone. The as-deposited microstructure of uniform TC17 and TC11 zones shows cyclic layer-like characteristics. For direct connection process, there exists an extremely narrow transition zone between TC17 and TC11 zones. Sharp changes both in chemical composition and microstructure are found between uniform TC17 and TC11 zones. For gradient connection process, the transition zone encompasses a wider region in which continuous changes of chemical composition and microhardness are found. The intermediate microstructure which is different from that of TC17 and TC11 emerges in the gradient transition zone. Room temperature tensile tests show that all as-deposited dual alloy samples regardless of connecting process are fractured in the TC11 zone, with approximate tensile strengths and dispersed elongations.