Investigating acoustic emission during macro-indentation of AZ 31 magnesium alloy

Accelerated mechanical characterization is crucial for enabling the rapid assessment of mechanical properties during process optimization or material development. This article introduces an innovative approach, combining profilometer-based indentation plastometry (PIP) with a real-time acoustic emission (AE) monitoring system. This approach assists in comprehensively assessing both mechanical properties and the underlying deformation mechanisms during indentation through AE emission. In this study, we investigate the effect of grain size variation on acoustic emission in AZ31 magnesium alloy during PIP indentation. Our findings demonstrate that PIP-inferred yield strength is notably higher (68 MPa) for samples with smaller grain sizes (70 mu m) compared to those with large grain sizes (98 mu m), with a yield strength of 46 MPa. Moreover, AE-energies are notably lower in samples with smaller grain sizes as opposed to those with larger grain sizes. To further gain insight into the dominant deformation mechanism, a non-supervised cluster analysis, in conjunction with electron backscattered diffraction (EBSD) analysis, reveals that the major deformation systems are basal dislocation glide {0001}(1120) and extension twinning {1012}(1011).