Implementing shear-punch test for the assessment of mechanical properties of cast and selective laser melted AlSi10Mg alloys

The aim of this investigation is to continue the numerous previous investigations into the selective laser melting (SLM) of the AlSi10Mg alloy while investigating the microstructural differences from the as-cast state in more detail and assessing the potential for predicting mechanical properties using small punch test methods. In this research, optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were carried out on SLM and cast samples in their original and heat-treated states. In addition, the mechanical properties were analyzed using the hardness test and the shear punch test over a temperature range of 25-400 degrees C. The results show that the initial microstructure of the SLM alloy consists of supersaturated solid solution and fine Si phase, and as the temperature rises, the second phases are formed in the micro- and nanoscale within the structure. Moreover, the hardness evaluation indicates that the SLM alloy has a hardness of approximately 50 Vickers higher than the cast alloy due to the supersaturated solid solution phase and having a significantly finer microstructure. The results of the shear punch analysis also show that the SLM alloy has a higher ultimate shear strength than the cast alloy at all temperatures up to 400 degrees C, and the slope of the decrease in ultimate shear strength becomes steeper after the transition temperatures in the range of 200-300 degrees C, but the SLM alloy still has superior strength to the cast alloy in terms of the Hall-Petch and Orwan strengthening mechanisms. Comparison of the variations in ultimate shear strength (USS) in this study with those previously presented for ultimate tensile strength (UTS) and ultimate compressive strength (UCS) shows that the changes in USS can be used to predict UCS and UTS using appropriate coefficients and formulae. In addition, by interpreting the results obtained, this study has proposed a framework for predicting fracture toughness (JIC) without the need to perform an impact test and from the results of the shear punch test for the AlSi10Mg alloy.