Influence of thermal exposure on the microstructures and mechanical properties of a superalloy

摘要: The effects of long-term aging on microstructures and their influence tensile stress-rupture behavior a corrosion resistant nickel-base superalloy are investigated. Samples aged isothermally at 1073, 1123, or 1173 K for different times up to 10,000 h mechanical tests performed samples in both standard heat treatment (SHT) conditions. Scanning electron microscopy (SEM) studies reveal that the coarsening kinetics γ′ follows linear law temperatures with calculated activation energy, i.e., 255 kJ/mol, growth according Lifshitz-Slyozof-Wagner (LSW) theory. After more than 1 khours, σ phase appears alloy. formation can be described by Johnson-Avrime-Mehl equation. Tensile experiments room temperature endurance K/274 MPa test effect phases these properties no remarkable harmful is found. used explain reduction yield stress, which tested Labusch-Schwarz hardening Although presence clearly does affect fracture process, not embrittle