APPLYING TEP MEASUREMENTS TO ASSESS THE RESPONSE OF HASTELLOY TO LONG TIME AGING

Hastelloy C‐276 service temperature is restricted due to precipitation of the intermetallic compound μ. Time‐temperature curves indicate that the highest precipitation rate is obtained at about 870° C. Thermoelectric Power (TEP) measurements were applied to monitor the precipitation kinetics during aging at 870° C. The TEP was found to be well correlated with the amount of μ phase formed during aging and with the reduction in impact energy and ductility. It was demonstrated that TEP measurements could be used to monitor aging of Hastelloy C‐276.