MICROSTRUCTURE AND PHASE STABILITY OF INCONEL ALLOY 617.

Abstract

A laboratory study was performed to determine the effects of long-time (215 to over 10,000 hr) exposure to temperatures up to 2000 degree F (1093 degree C) on the microstructure and phase stability of a 54Ni-22Cr-12. 5Co, 9 Mo-1Al-0. 007C alloy. Microstructures were correlated with mechanical properties. Strengthening of the alloy during exposure to temperature was found to result primarily from the precipitation of M//2//3C//6. The phase precipitates in discrete particles and remains stable at temperatures to 2000 degree F (1093 degree C). The amount of gamma prime formed is not sufficient to cause appreciable hardening, but it does provide some strengthening at 1200 to 1400 degree F (649 to 760 degree C).