Application of Response Surface Methodology for Optimizing Direct Thermal Method Parameters of Al-Si Alloys with Mg Addition
摘要
This study examines the effects of varying processing parameters, including pouring temperature (590, 610, 630 °C), holding time (10, 15, 20 s), and magnesium addition (0.5, 1, 1.5 wt.%), on the Al-Si alloy. The semi-solid feedstock billets were produced using the direct thermal method (DTM). Additionally, an extra sample with a pouring temperature of 590 °C and a holding time of 20 s was produced without magnesium addition to serve as a reference. The samples underwent mechanical testing, including density measurement, tensile, and Vickers hardness tests. The results showed that sample 7, with a pouring temperature of 590 °C, a holding time of 15 s, and a magnesium addition of 1.5 wt.%, has the highest density value, UTS, YS, and Vickers hardness value at 2.7 g/cm3, 147 MPa, 113 MPa, and 137 HV. Meanwhile, sample 16 without magnesium addition has the lowest density and mechanical properties, with a density, UTS, YS, and Vickers hardness value of 2.53 g/cm3, 44 MPa, 36 MPa, and73 HV, respectively. It was apparent that the sample with magnesium addition had better mechanical properties than those without magnesium addition. The samples exhibited dimple cracks, demonstrating the alloys’ ductile fracture characteristic. RSM has explored the optimal combination of pouring temperature, holding time, and magnesium addition to produce Al-Si alloy semi-solid feedstock billets with the desired mechanical properties, as produced via DTM. Experimental and predicted values show a good level of agreement. The experimental findings elucidate the impact of magnesium addition on the mechanical characteristics of the Al-Si alloy, which is well-suited for SSM processing.