Microstructure and mechanical properties of Al-Si alloys produced by sprayforming process

The microstructural characteristics and mechanical properties of Al-6.5Si a nd Al-18Si alloys have been investigated The alloys were spray-deposited an d hot extruded at 480 degreesC with an area reduction ratio of 6:1. The mic rostructure of the spray-deposit of Al-6.5Si alloy showed spherical morphol ogy of the primary or-phase with a globular shape of the eutectic Si phase in the inter-particle boundaries. On the other hand, a fine particulate mor phology of primary Si phase uniformly dispersed in the matric of the alpha -phase was observed in spray-deposit of Al-18Si alloy, Microstructural refi nement was further increased in the hot extruded alloys. The room temperatu re tensile tests of spray formed and extruded alloys showed considerable in crease in their strength and ductility over that of the as cast alloys. The improvement in mechanical properties of spray formed alloys is discussed i n light of the microstructural modifications induced during spray depositio n process. (C) 2001. Elsevier Science B.V. All rights reserved.