Multi-scale modeling of aging of Waspaloy superalloy: prediction of microstructure evolution and coupling with mechanical properties

Ni-based superalloys operating under challenging conditions require high mechanical strength at elevated temperatures where heat treatment processes are crucial for those materials including solutionizing and aging. The yield strength of these alloys arises concurrently from different strengthening mechanisms and the main strengthening mechanism for an alloy can change depending on the composition and processing methods. Starting from solidification, the optimum solutionizing temperature for Waspaloy is determined and isothermal aging parameters were set with ICME methods where results were compared with physical experiments. By using the modeling results, yield strength estimation was conducted from room temperature to operational temperatures and validated with thermomechanical experiments. Orowan and coherency strengthening were each found to have a great impact on yield strength, showing the importance of heat treatment processes on Waspaloy. The methods described and the model developed can be used for refining composition and microstructure to have the desired strength.