Effect of Nb Content on Microstructure and Mechanical Properties of K4169-Type Superalloy

The influence of Nb content on the microstructure and mechanical property of K4169-type superalloy was investigated by using optical microscopy, scanning electron microscopy, transmission electron microscopy observation and tensile testing, at room temperature and 650 degrees C, respectively. Two alloys with different Nb contents (4.9 wt.% for Alloy 1 and 8.9 wt.% for Alloy 2) were investigated in this work. The results show that with the aging temperature increasing from 620 to 720 degrees C, the strength of Alloy 1 and Alloy 2 increases, which is further enhanced during two-stage aging. Comparably, Alloy 2 has higher ultimate tensile strength at room temperature and 650 degrees C, and better high-temperature resistance while its elongation is significantly lower. After aging, the number of carbides does not change significantly, but as the number of Laves and delta phases increases, the size and content of gamma '' phase raises in Alloy 2 as well.

Automated summary

The influence of Nb content on the microstructure and mechanical property of K4169-type superalloy was investigated in this study. It was found that increasing Nb content can improve the strength and high-temperature resistance of the alloy, but may reduce elongation. Additionally, with the increase of aging temperature, the strength of the alloy will increase.