The Effect of Heat Treatment Temperature on Superalloy Inconel 713 hardness and Microstructure

The Inconel 713 Superalloy was used for turbocharged blades in the automobile industry. In this paper, changes in the microstructure and the hardness was studied as the temperature of the full and the partly solution heat treatments was changed in the range of 1000 to 1200°C in 1 hour. For studying the hardness of superalloy the Rockwell C hardness test was used and also the optical and the Scanning Electron Microscopy and the Electron Dispersive Spectroscopy and the X-ray Diffraction (XRD) was used to detect the microstructure and the present phases in the superalloy. The results showed that the significant change in the phases were observed when the temperature range was 100°C. The heat treatment caused to solute chromium carbides in the γ matrix. In addition, by increasing the heat treatment temperature, the γ` phase dissolved in (200) and (220) plane and this phase in the plane of (111) had the best stability in 1000°C. Phases of Ni5Al3, NiAl and Al0.42Ni0.58 were observed in the temperature of 1000, 1100 and 1200°C, respectively. As the temperature of the heat treatment increased the hardness increased 25 percent.