INVESTIGATION OF HEAT TREATMENT PARAMETERS EFFECT ON THE MICROSTRUCTURE AND ON THE MECHANICAL PROPERTIES OF A POWDER METALLURGY NICKEL-BASE SUPERALLOY

The relationships between heat treatment parameters and microstructure, and between microstructure and mechanical properties were investigated in the SMO43 disc P/M superalloy. Various heat treatments were applied to this superalloy to determine the effect of the solution temperature on the grain size, and of the cooling path and aging temperature on the gamma' precipitates distribution. Microstructural features were characterised through the careful study of gamma' precipitation. Fatigue crack growth tests with dwell time were performed at high temperature for comparison of the mechanical properties of some selected microstructures.