New approach to evaluate the quench cracking resistance

摘要

Large turbine disks of advanced aircraft engines require a rapid cooling after solution annealing to achieve the desirable strength. Quench cracks may form unexpectedly on the surface of tubine disks. A fracture mechanics approack was used to measure the on-cooling fracture toughness of a high-strength P/M superalloy, Rene 95. The simulation included the precracked single-edge-notched (SEN) specimen with a fixed displacement holding at solutioning temperature. Thermal stress was indcued as the temperature is decreased, and a catastrophic fracture ouccurred at certain temperatures. The measured quench cracking toughness of P/M Rene 95 is about an order of magnitude lower than that of room temperature fracture toughness.