Effect of sintering time on the microstructure and properties of Al- Al2Cu composites produced by powder metallurgy

Powder metallurgy method has been utilized to produce Al-Al2Cu composites. A powder mixture of commercially pure Al (in the size range of 38-75 μm) and 20 wt.% of <45 μm sized pure Cu powders was cold pressed and sintered at 600 ˚C in a tube furnace for different times ranging from 15 to 60min. The Al and Cu powders were chemically treated with 1% NaOH and 15% HCl respectively to ensure their surface activation before blending. XRD and SEM studies on the sintered samples confirmed the presence of Al-Al2Cu eutectic at the interface of two metals that formed in situ during the reaction sintering. The intermetallic compound of Al2Cu distributed uniformly within the matrix alloy and served as the reinforcing phase in the composites. The effect of sintering time on the microstructure, porosity, microhardness and hardness of the produced composites was investigated. The increased sintering time resulted in increased microhardness of Al (Cu) phase and hardness of composites significantly.