Optimization of Hot Workability and Microstructure Control during Hot Working of Nickel-Based Superalloy XH62: A Processing Map Approach
摘要
The hot deformation behavior of an alloy is significantly influenced by its constituent alloying elements. Nickel base superalloys, such as the XH62 alloy, have been modified with multiple alloying elements to impart high-temperature strength and creep resistance. However, modifications to the chemistry of the alloy have led to increased microstructural complexity, posing several challenges during thermo-mechanical processing. In this paper, we aim to determine the optimal combination of strain rate and temperature for thermo-mechanical processing of XH62 alloy. To achieve this, isothermal hot compression test was conducted on as-cast samples of the XH62 alloy in a wide range of temperatures (1050-1200 °C) and different strain rates (10-3-10 s-1). The deformation behavior was analyzed by examining flow curves, establishing empirical relationships, and generating a processing map that distinguishes stable and unstable domains. The microstructural changes in the samples following hot compression tests have been correlated to the stable and unstable regions of the XH62 processing map. This paper not only addresses the challenges associated with secondary processing of complex superalloys but also presents practical guidelines for optimizing the forging parameters, thereby facilitating the production of high-quality components.