Aging Behavior and Microstructure Evolution of a Cold-Drawn Ni-Co Superalloy


1 Institute for Technology Development, Tehran, Iran

2 Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran


Age hardening behavior and microstructure of superalloy AEREX 350TM in commercially cold-drawn condition were studied. It was found that aging the cold drawn alloy significantly facilitated the formation of major phases of gamma prime and eta, in AEREX 350TM. Interestingly, the minimum temperature of formation of gamma prime and eta phases in the cold drawn alloy was lower by about 30°C and 5°C, respectively, to that previously reported for the solution treated alloy. Cold working, however, did not considerably influence the maximum temperature of stability of these phases. In addition, Widmanstätten morphology of eta phase significantly improved in the cold drawn samples compared to that seen in the solution treated alloy. Diffusion through dislocation network could have facilitated growth of major phases whereas its influence on dissolution temperature of these phases was negligible. In addition, it was suggested that cold working might increase the density of hcp nuclei in the fcc matrix. This may justify the observed enhancement of the Widmanstätten morphology of eta phase in these samples following the aging process.