Alloy design and development of INCONEL718 type alloy

The effect of alloying elements such as Al, Ti, Nb, W and Co in INCONEL 718 type alloys on phase precipitation behavior has been investigated by means of Thermo-Calc software. The results show that both the solvus temperature and fraction of phases in 718 type alloys has been significantly changed with variation these alloying elements. The experimental results also reveal that precipitation kinetics of δ, γ″ and γ′ phases in developed 718 type alloys have been changed. The alloy with higher content of Al shows microstructural stability superior to that of conventional 718 alloy. Based on thermodynamical and experimental results, the optimum content of Al, Ti and Nb of the developed 718 type alloy without W and Co additions has been determined to be 1%, 1% and 5.5%, respectively.