The effect of ageing temperature and time on the mechanical properties of Fe-NiCrMo alloys with different contents of δ ferrite

Laboratory cast alloys with 2-27% of delta ferrite were aged for up to 17,520 h in the temperature range 290-350 degrees C. Tensile and Charpy tests were performed at 22 and 290 degrees C on specimens aged for different times, and the microhardnesses of both constituents of the microstructure were determined for the alloy with 27% of delta ferrite. The effects of the content of delta ferrite, the ageing and testing temperature, and the ageing time on mechanical properties and notch toughness are presented and discussed. (C) 2008 Elsevier B.V. All rights reserved.