Quantitative characterization of two-stage homogenization treatment of alloy 718

Segregation behavior of a f406 mm Alloy 718 ingot was investigated and two-stage homogenization treatment was employed to relieve the micro-segregation between dendrite structures. In the first stage homogenization, the Laves phase elimination percentage was expressed dependence of two parameters (time and temperature). In order to characterize the effects of second stage homogenization, a 900i/1 h treatment was conducted after homogenization, which could form  phase (Nb-riched) to trace the diffusion of Nb. It was found that average composition of -phase area, quantity of -phase precipitation and size of -phase precipitation would change with the proceeding of homogeniation. As a result, homogenous structure can be achieved by means of a two-stage homogenization treatment (1140i/60 h + 1190i/30 h). (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.