Extruded aluminum-free magnesium alloys containing zirconium, zinc and neodymium (ZK10 and ZN11) in a form of rectangular profiles were deformed at room temperature and at a constant strain rate of 10-3 s-1. Uniaxial tensile and compression tests were performed in the extrusion (ED), the transversal (TD) and normal direction (ND). The concurrent acoustic emission (AE) measurement was used in order to study the collective dislocation dynamic and the nucleation of twins during plastic deformation. The AE events, stemmed from collective dislocation movement and twin nucleation, were identified using statistical analysis of the raw AE signal (ASK analysis).
The results of AE measurements were proved by X-ray texture measurements. Compression tests were stopped at points of interests and texture evolution was examined. The twin volume fraction was investigated by electron backscattered diffraction (EBSD) measurements.
The results of X-ray diffraction have shown that both Mg alloys exhibit a significant texture with basal planes nearly parallel to the ED and perpendicular to the ND. In ZN11 alloy were also observed some basal planes perpendicular to the TD. The AE signals were correlated with the deformation curves and the maximum of the AE activity was found at the macroscopic yield point. During tensile loading in both Mg alloys, a relative high AE activity persists till the end of the test, while in compression only the ZN11 alloy exhibits a significant AE activity after the yield point.