Microstructure evolution in a Ni–Mo–Cr superalloy subjected to simulated heat-affected zone thermal cycle with high peak temperature

Abstract

Abstract A typical Ni–Mo–Cr superalloy with basic composition of Ni–17Mo–7Cr (wt.%) was fabricated and the relationship between the microstructure and mechanical properties while it underwent simulated heat-affected zone thermal cycle (HAZ) treatment was investigated. The results show that the Ni–Mo–Cr alloy was mainly made up of Ni based solid solution and MoC carbides. The critical peak temperature that a unique lamellar-like structure occurred in the alloy was found to be 1300 °C, and they were firstly determined to be Ni matrix and carbides (MoC and chromium carbides) generated through local melting. Due to the formation of unique structure, the alloy exposed to HAZ thermal cycle with a peak temperature of 1300 °C could still maintain excellent high-temperature mechanical performance. The work carried out here will provide valuable guidelines in designing and applying the Ni–Mo–Cr series superalloys.