Twinning and texture development in two Mg alloys subjected to loading along three different strain paths

The evolution of twinning and texture in two Mg-based (+Al, NIn, Zn) alloys was investigated using uniaxial tension, uniaxial compression and ring hoop tension testing at temperatures from ambient to 250 degrees C and a strain rate of 0.1 s(-1). The results indicate that the initial extrusion texture plays an important role in the formation of different types of twins and that the twinning behavior also depends on the strain path. Contraction and double twinning are the dominant twinning mechanisms in uniaxial tension, while extension twinning prevails in uniaxial compression and ring hoop tension testing. Schmid factor analysis indicates that only components that are favorably oriented (i.e., with the highest SF values) can undergo rapid and complete twinning. The different twinning behaviors are shown to be responsible for the sharply contrasting strain hardening characteristics of the experimental flow curves and dramatic texture changes. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.