Abstrakt
The influence of the pre-compression level on subsequent tensile deformation behavior has been investigated for two extruded Mg alloys with a different grain size distribution. The Mg-Zn-R are earth alloy has homogeneous microstructure, while the Mg-Al-Zn alloy exhibits bimodal microstructure.
Deformation tests were performed at room temperature and at a constant strain rate of 10(-3) s(-1). Three pre-compression stress levels were chosen to receive microstructure containing a low number of twins, partially and fully twinned grains, respectively.
The concurrent acoustic emission (AE) measurement provides real time information about collective dislocation motion and twin nucleation. Active deformation mechanisms during tensile loading are discussed in term of the AE response.