Investigation Mechanical and Microstruct

This study examines the mechanical and microstructural behaviors of polycrystalline Ni-based super-alloy Mar M-247 turbine rotor discs, specifically comparing operated and unoperated samples used in turbojet engines. The primary objective was to analyze the influence of operational conditions on the microstructure, which included identifying the characteristics of primary and secondary carbides found within the gamma matrix, and noting the precipitation of Hf, Ta, and Ti elements as MC carbides. Employing a series of experimental procedures, six samples were extracted from both types of rotor discs, which were subjected to high-temperature tensile tests, hardness assessments, and microstructural analysis. The findings revealed that the high-temperature operational conditions led to distinct microstructural changes, including the formation of M23C6 secondary carbides at grain boundaries, contributing to an increase in gamma prime volume and solid solution hardening of the alloy. These insights enhance our understanding of the mechanical performance of turbine rotors under varying operational stresses and temperatures, ultimately informing better design and material selection in aerospace applications.