Microstructural Evolution and Mechanical Properties of Investment-Cast Haynes 282 Nickel-Based Superalloy After Heat Treatment and High-Temperature Thermomechanical Processing

This study analyzed the effect of a processing sequence comprising precision casting, heat treatment, and high-temperature plastic deformation on the microstructure and mechanical properties of the Haynes 282 nickel superalloy. The starting material was prepared in an industrial VIM IC induction furnace under vacuum conditions; the quality of the resulting castings, phase composition, thermal effects, and the alloy’s behavior during uniaxial compression were then evaluated. Castings in the form of rods with diameters of 10, 12, and 16 mm were produced at a molten alloy temperature of 1550 °C and a ceramic mold temperature of 1250 °C. The lowest porosity values, ranging from approximately 0.036–0.16%, were obtained for the vacuum furnace cooling variant, which was selected for further testing. DTA analysis revealed characteristic thermal effects in the range of 935.9–1379.8 °C, which enabled the selection of supersaturation parameters and a safe range for deformation tests. After supersaturation and aging, the samples were compressed at temperatures of 700–1200 °C at strain rates of 0.001 s−1 and 0.008 s−1. An increase in temperature caused a systematic decrease in maximum stress and yield stress, with the highest plastic resistance observed at temperatures of 700–800 °C. In this range, the microstructure exhibited characteristics of strong strain hardening, high dislocation density, and strain localization. At temperatures of 850–1000 °C, a transition to conditions of intense dynamic recovery and dynamic recrystallization was observed, whereas above 1050 °C, grain growth following recrystallization dominated. The most favorable compromise between reducing deformation resistance, minimizing the risk of cracking, and maintaining a finer microstructure was achieved in the 900–1000 °C range. The results indicate that the combination of precision casting and controlled thermomechanical working can serve as the basis for further optimization of the manufacturing technology for Haynes 282 superalloy semi-finished products.