Effects of Ru on Microstructure and Stress Ruputure Property of Ni-based Single Crystal Superalloy DD22

Literature information

Author：

LUO Yushi1 ZHAO Yunsong1,2 YANG Shuai1 ZHANG Jian1 TANG Dingzhong1

Affiliations：

Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing, China 100095;State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, B

Year：

2016

Keywords：

single crystal superalloy; Ru; microstructure; stress rupture property; TCP phase;

Abstract：

The effects of Ru on the as-cast, heat-treated microstructures and stress rupture properties under 1 100-1 150 °C were investigated in new generation Ni-based single crystal superalloys DD22 with two levels of Ru (0% and 2%, mass fraction) additions. The results indicate that the addition of Ru results in the decrease of the solidus and liquidus temperatures, the volume fraction of (γ+γ') eutectic as well as solidification segregation. The size of γ' phase and elemental partitioning ratio of Re and Cr which are important for the precipitation of TCP phase decreases after heat treatment with Ru addition. Ru addition decreases the size of γ' phase, increases γ/γ' misfit and solution strengthening effect and inhibits the precipitation of TCP phase in the process of stress rupture loading, which finally improve the stress rupture properties of DD22 alloy significantly.