In situ synchrotron analysis of twinning stresses in an aged mg-4.5zn alloy

Aging increases the yield strength of aged Mg-Zn alloys. The effect of aging on the stress required for twinning is examined using in-situ transmission based synchrotron X-ray diffraction. The as extruded material was aged at variety of temperatures for different times. It is found that increasing sample diameter (thickness) results in peak broadening. The data are analysed to establish the evolution of twin volume fraction with stress. Results indicated an increase in twinning stress at 10% twin volume fraction in aged samples in comparison with non-aged condition. The investigation showed a strong relation between the macroscopic yield stress and the twinning stress (at 10% twin volume fraction).