Characterization of high temperature deformation behavior of INCONEL 617

INCONEL 617 (UNS N06617, also referred as Alloy 617) is an austenitic Ni–22Cr–12Co–9Mo alloy, which is a candidate structural material for next generation high temperature nuclear reactors. High temperature deformation behavior of Alloy 617 has been investigated as a function of strain rate ranging from 10−3 to 10−6 s−1 at 600 and 800 °C. Increase in the temperature and decrease in the strain rate decreased the flow stress of the material. Serrated flow was observed at both the test temperatures. The amplitude of serration increased with decrease in the strain rate and increase in the temperature. Microstructural analysis showed that deformation at slow strain rates increased both the grain size and volume fraction of second phase precipitation. Furthermore at slower strain rates, increase in the carbides size and a continuous network of carbides along the grain boundary could be observed. Scanning Kelvin Probe Force Microscopy (SKPFM) was performed on the tested specimen to observe variation in surface potential as a result of microstructural degradation during high temperature deformation at different strain rates. The second phase precipitates of the specimens deformed at higher strain rate (10−3 s−1) showed more positive surface potentials than that of the specimens deformed at slower strain rate.