High-temperature mechanical properties of Inconel-625: Role of carbides and delta phase

Abstract

Based on the temperature sensitivity characteristics, high-temperature tensile tests were performed at different temperatures and after different solid solution treatments to investigate the effect of Cr-rich M₂₃C₆, Nb-rich MC and the delta phase on the mechanical properties of Inconel 625. The experimental results indicated that the Cr-rich M₂₃C₆ carbides and the Nb-rich MC carbides decomposed at 700°C, which could be the reason for resulting tensile strength anomaly that was observed in a narrow temperature range from 650 to 700°C during the tensile tests at different temperatures. For the samples subjected to a prior solid solution treatment, the size of the δ phase was found to increase with the solution treatment temperature, whereas the elongation at fracture decreased.