Flow behaviors and processing maps of as-cast and as-homogenized AZ91 alloy

Abstract

Compression tests of as-cast and as-homogenized AZ91 alloy were performed at the temperature range from 473 K to 673 K and the strain rate range from 0.001 s −1 to 5 s −1, and the flow stress data obtained from the tests were used to develop the processing maps. By analysis, the main differences are as follows: the flow stress of the as-cast AZ91 alloy is higher at the lower temperatures (473 K) because of the strengthening β-phase distributing along grain boundaries. The efficiency of power dissipation of as-homogenized AZ91 alloy is greater than the as-cast state below 650 K because of a larger proportion of twining and/or DRX, and the as-homogenized state still owes the characteristics of stable flow at 473 K/0.001 s −1. The optimum deformation parameters gained by the processing maps and microstructure are the same for different states, and the temperature and strain rate, respectively, are range from 623 K to 673 K and from 0.001 s −1 to 0.03 s −1.