Properties of Nimonic 80A alloy with change in the chemical compositions and Heat Treatment Paths

Abstract

Properties of Ni-base superalloys of Nimonic 80A alloy system were investigated by the observation of microstructures, precipitates ana hardness as a function of the chemical compositions ana the paths of heat treatment. The higher hardness values showed, the higher Ti/Al ratio among high compositions of Cr and Co element. The lower (Ti+Al) and Fe contents decreased in the same Ti/Al ratio, the higher hardness values showed. This results are considered that coherent deformation was increased with increasing Ti/Al ratio. Hardness showed higher value when Cr contents was <TEX>$18 wt\%$</TEX> less than <TEX>$21wt\%Cr$</TEX>. In <TEX>$3.15 wt\%$</TEX>Co alloy, <TEX>$\gamma'$</TEX> phase was very fine as around 50nm and, its volume fraction and hardness showed the highest value by 2step-aging treatment.