IN625 alloy was prepared by plasma jet welding machine

and the effect of surfacing current and post heat treatment on microstructure and mechanical properties of the surfaced IN625 alloy was investigated. The results showed that the microstructure of the surfaced IN625 alloy consisted of the orientational dendrite Laves phase and austenite. The content of dendrite Laves was increased and its morphology was coarsened with the increase of surfacing current

the microhardness of the surfaced IN625 alloy was decreased from 230 HV to about 190 HV. The partial Laves in the surfaced IN625 alloy was dissolved and refined after solution treatment at 1 180 ℃

and the microhardness and the tensile strength were increased to 310 HV and 872 MPa

respectively. While the microstructure of the surfaced IN625 alloy was coarsened and the microhardness was decreased after solution treatment at 1 200 ℃.The microhardness and the tensile strength of the solution-aging treated IN625 alloy were lower than that of the solution treated alloy.The content of dendrite Laves in the solution-aging treated IN625 alloy was increased and its microhardness was decreased with the increase of welding current. The fracture mechanism of the surfaced IN625 alloy before and after heat treatment was ductile fracture

and the dimple in the fracture surface of heat treated IN625 alloy was presented as small size

showing good toughness.