Effects of Heat Treatment on Tensile and Creep-Rupture Properties of 713LC Ni-based Superalloy

摘要

Microstructure and creep-rupture property of Alloy 713LC were investigated to optimize the utility of Alloy 713LC The applied heat treatment condition was 1170 deg C/2hours/air cooling followed by 650 deg C/l6hours/air cooling. During the heat treatment at 1170 deg C, MC carbide on grain boundary of as-cast Alloy 713LC was partially dissolved and coarsening of #gamma#' particles was contemporaneously taken place so that inhomogeneous distribution in size of #gamma#' particles was observed in heat-treated Alloy 713LC. It was concluded from the high temperature tensile test that the equi-cohesive temperature(ECT) of Alloy 713LC is around 750 deg C. At higher temperature than ECT, stress-rupture time was not changed after heat treatment. On the other hand, at the temperature around ECT, stress-rupture time decreased by the factor of 10 after heat treatment. This was explained by relating it to the microstructural change of grain boundary and grain interior caused by heat treatment.