Interdiffusion Of Alloying Elements In Ni Based Alloys

The present paper reports the interdiffusion in the system of Ni-Al-X where X being Re, W, Ru, and Co and evaluates the interaction between X and Al as the γ’-forming element. The four ternary interdiffusion coefficients in these systems are determined by adopting the method developed by Whittle and Green. The results show that the major interdiffusion coefficients of the elements in each system are positive and have larger values compared to the cross one indicating that the influence of their concentration gradients on their own fluxes is generally still dominant. It is observed from  /  that the contribution of Re concentration gradient on the Al diffusion flux is greater than those of other elements X. Furthermore, / for X= Re, W and Ru has large negative values indicating that these elements tend to diffuse up the concentration gradient of Al or, in other words, toward the higher Al content area. This suggests that the interaction of the elements Re, W and Ru with Al is attractive in the γ phase of nickel based alloys. It indicates that Re, W, and Ru appear to be the potent elements in controlling the formation and the evolution of the γ’ phase. Metalurgi Vol. 24 No. 1 Juli 2009