An investigation was conducted to study the effects of several heat treatments on the operating life of turbine blades in a J33-33 turbojet engine operated without an afterburner. As-forged blades, blades solu¬tion treated at temperatures high enough to produce germinated grains, blades given a double-aging treatment, and blades overaged by overtem-perature heat treatments were evaluated. The engine was operated in a cyclic manner, 15 minutes at rated speed and 5 minutes at idle.nThe as-forged group of blades and the group of blades aged without prior solution treatment performed twice as well as a group of blades given the standard AMS heat treatment for S-816 (AMS 5765A) and performed better than all other groups of heat-treated- blades. The superior per¬formance of these groups of blades was associated with a high hardness and a dense and uniform precipitation of carbides throughout the micro-atructures. The forging operations were concluded to be responsible for the superior performance of these groups by strain-hardening the matrix prior to engine operation and by promoting the unifofctn and dense precipi¬tation of carbides during engine operation.
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