Effect of Nb on δ Phase Precipitation and the Tensile Properties in Cast Alloy IN625

• Main Authors: Yiqiang Mu, Changshuai Wang, Wenlong Zhou, Lanzhang Zhou
• Format: Article
• Language: English
• Published: MDPI AG 2018-01-01
• Series: Metals
• Subjects: δ phase precipitation; element Nb; tensile properties; cast alloy IN625
• Online Access: http://www.mdpi.com/2075-4701/8/2/86

Cast alloy IN625 is a candidate Ni-base alloy for advanced ultra-supercritical (A-USC) power plants. The aim of this study was to investigate the influences of Nb on δ phase precipitation and the tensile properties in this alloy. The results show that the δ phase is easy to precipitate after long-term aging at 700 °C (the service temperature of A-USC power plants) and it is strongly affected by the content of Nb in the alloy. The strength of alloys after aging at 700 °C for 10,000 h increases with the increasing Nb content and also increases sharply when compared to that of as-heat-treated alloys. The increase in strength is found to be primarily associated with the precipitation of the δ phase.