Effect of heat treatments on Inconel 625 fabricated by wire and arc additive manufacturing: An in situ synchrotron X-ray diffraction analysis
Tiago A. Rodrigues, Francisco Werley Cipriano Farias, Julián Arnaldo Ávila, Emad Maawad, Norbert Schell, Telmo G. Santos, J.P. Oliveira
Abstract
The effect of heat treatments on wire and arc additively manufactured Inconel 625 parts was investigated using in situ synchrotron X-ray diffraction and hardness testing. As-built samples revealed the presence of a γ-matrix with precipitation of γ′, γ′′ and MC carbides. When heat treated at 750°C for 4 h, γ′′ phase precipitated increasing the hardness by 5%. In situ X-ray observations revealed that heat treating at 870°C for 1 h resulted in δ-phase precipitation. Two different second-stage temperatures were tested (1050°C and 1150°C), which dissolved the δ-phase while MC carbides formed upon cooling. The second stage at 1150°C had a higher deleterious effect than the one performed at 1050°C due to extensive grain growth.