Evaluation of impact and hardness properties of Al 6063-AgNPs composites produced by stir cast technique

Abstract

The effect of silver nanoparticles (AgNPs) on the mechanical and microstructural properties of aluminium 6063 alloy was investigated. Aluminium 6063 matrix was homogenously mixed with AgNPs impregnated with calcium carbonate at 2, 4 and 6% weight fractions. The mixture was used to produce refined samples through stir casting method. Measurement of impact strength and hardness property of the produced samples at ambient temperature was done by using Charpy impact and Brinell hardness testing machine in accordance with ASTM E23 and ASTM E384 respectively. The impact energy values (234-247 J) of all the samples with AgNPs/CaCO3 reinforcements were higher than the as-cast Al alloy (228 J) while the sample with 6% AgNp has the highest energy impact (247 J). Similarly, the hardness values (56.49-183.70 BHN) of all the samples with AgNPs/CaCO3 reinforcements were higher than the as-cast Al alloy (38.05 BHN) while the sample with 6% AgNPs has the highest (183.70 BHN). The magnitude of impact and hardness increased evidently with increase in percentage weight fraction of the AgNPs. The fracture images of the impact test samples revealed that the surface of AgNPs (CaCO3)-Al6063 composites were with dimples and there was a micro-void formation in CaCO3-Al6063 composite. The use of stir-casting technique influenced the homogeneity and microstructure of the AgNPs composites positively. The Al 6063-Ag nanocomposites possess better qualities in terms of impact energy and hardness, likewise can replace conventional aluminium alloy based on its performance.