Effects of Laser Cladding on Thermal Tensile Property and Fracture of Gas Turbine Engine Blade Material GH864

摘要

The consecutive layer of a nickel alloy was deposited onto a GH864 nickel-based superalloy gas turbine engine blade using laser cladding. To ensure the performance of blade, the gas turbine with laser cladding repaired blades worked two weeks and a detailed measurement and investigation were performed on chemical composition, mechanical performance, microstructure, macro-fractography and micro-fractography. The results indicate that the cracks at the inlet edge part of blade were caused by reheat crack. An inappropriate technology of laser cladding can result in the formation of incomplete fusion interface between the laser clad coating and substrate, or reheat cracking along the coarse grain boundary in the heat treatment zone. Tensile specimens were tested at both room temperature and elevated temperature. The results correlate to the conclusion that the reheat crack is the main reason for the performance degradation of the restored blade.