Microstructure, mechanical and thermo-physical properties of Al/Al−27%Si laminated composites

Abstract

Three types of Al/Al−27%Si laminated composites, each containing 22% Si, were fabricated via hot pressing and hot rolling. The microstructures, mechanical properties and thermo-physical properties of these composites were investigated. The results demonstrated that the three laminated composites exhibited similar microstructural features, characterized by well-bonded interfaces between the Al layer and the Al−27%Si alloy layer. The tensile and flexural strengths of the composites were significantly higher than those of both Al−22%Si and Al−27%Si alloys. These strengths increased gradually with decreasing the layer thickness, reaching peak values of 222.5 and 407.4 MPa, respectively. Crack deflection was observed in the cross-sections of the bending fracture surfaces, which contributed to the enhanced strength and toughness. In terms of thermo-physical properties, the thermal conductivity of the composites was lower than that of Al−22%Si and Al−27%Si alloys. The minimum reductions in thermal conductivity were 6.8% and 0.9% for the T3 laminated composite, respectively. Additionally, the coefficient of thermal expansion of the composites was improved, exhibiting varying temperature-dependent behaviors.