Publication

Abstract : The existing work deals with the development of Al-Si-Mg-Ni hypoeutectic alloys and to investigate the impact of solutionising time on their morphology and how these alloys behave mechanically. Al, Si, Mg, Ni of required weight percentages were melted into a clay graphite crucible and the mixture was poured into a permanent mould from which cast rods of ø32 mm ×156 mm in length were obtained. The cast rods were solutionised at 538 °C for 2, 4, 6, 8 and 10 h, respectively. Further, the alloys were then quenched into 30 °C water and subsequently aged at 155 °C for 12 h. It is perceived from the investigation that, as the solutionising time increases, a refinement in the grain of the developed alloy occurs and the hardness and tensile properties were seen increasing. Moreover, ductility was found to be low for the alloy solutionised at 10 h as compared to the LM25 alloy. The scanning electron images of the fractured surface revealed that the increase of solutionising time from 2 to 10 h led to a much smaller extent of the observance of dimples on the fractograph. Furthermore, the fractured surface of the alloy solutionised for 10 h depicted the presence of micro-voids, which confirms the ceasing of ductile behaviour because of longer solutionising time.