Mechanical behavior of Al–Cu binary alloy system/ Cu particulates reinforced metal-metal composites

Abstract

Aluminium composite metallic materials are prepared by stir-cast technique, reinforcing 5 ​wt% copper powder (50 ​μm size) in Al–5wt% Cu alloy. SEM structures shows Cu particles not alloyed with the matrix material. EDAX studies inveterate the existence of elements in both binary alloys and the composite. Optical microstructures show uniform distribution of Cu particles in the Al–Cu alloy matrix. Richer alloy show 13% greater hardness compared to lean alloy. Enhanced precipitation of CuAl2 population around copper particulates observed. Cast fingers of Al-5wt% and Al-10 ​wt% Cu alloys and composite are homogenized at 100 ​°C for 24 ​h, resulted in more uniform distribution of the CuAl2 population. Standard samples of 3 ​mm thick discs solutionized at 450 ​°C for 2 ​h are aged at 190 ​°C to determine T6 condition. The peripheral increase in hardness is observed due to the increased Cu content because of solid-solution strengthening only. Alloy with 10 ​wt% Cu content show a decrease in tensile strength compared to 5 ​wt% alloy. This is due to the increased phase in interdendritic region of α-phase solid solution. Tensile property of 5 ​wt% Cu alloy is higher compared to 10 ​wt% alloy and composite, after ageing. Keywords: Composite metallic materials, Copper rich alloy, Solid-solution strengthening