Effect of strain rate on microstructure and mechanical properties of a Mg-9Li-2Zn alloy sheet

摘要

A two-phase Mg-9Li-2Zn alloy sheet is made by cold-rolling at room temperature, and the form-ability of it at room temperature is investigated in this study. Uniaxial tension tests are carried out for various strain rates between 0.5 mm/min and 250 mm/min, and the microstructural changes during the tests are observed. The sheet has high formability at comparatively low strain rates. Maximum elongation amounts to 40%. However, ductility decreases with the increase of strain rate. Even at room temperature, the stress is also sensitive to the strain rate. There are many large dimples at comparatively low strain rates, and small dimples occur at high strain rates, it shows fine sub-grains come into being.