Effect of Zr and/or V addition on structural and mechanical properties of Al-Si alloys

Aluminum alloys are the second mostly used metal group after steels due to their light weight, high relative strength and superior corrosion/oxidation resistance in structural applications. The superior physical and mechanical properties of aluminum alloys strongly depend on the applied heat treatment and the type and amount of alloying element. Al-Si based cast alloys are the most preferred group in the automotive industry for reasons such as reducing fuel consumption and lightening vehicles. However, for an Al alloy to be used as a potential material for steel in vehicles, their mechanical properties need to be further increased. In this manner, it is aimed to increase the mechanical properties of commercial AlSi10Mg cast alloy, which is used in the automotive industry, by addition of Zr and/or V. İn the present study, the alloys were produced by metal mold casting method and subsequently heat treated (T6 heat-treatment solutionizing at 500 °C for 1 hour and aging at 190 °C for 1, 4, 16 and 64 hourg). The effects of Zr and/or V addition on the microstructure, phase relationships, transformation temperatures and mechanical properties of commercial AlSi10Mg alloy were investigated in detail. The microstructure of the alloys was investigated by optical microscope, phase analysis was performed with, X-ray diffraction (XRD) and eutectic transformation temperatures were measured by thermal analysis method. The mechanical properties of the as-cast and heat treated samples were determined by Brinell hardness and tensile tests. Although the addition of Zr and/or V did not have much effect on the microstructure and other structural properties, it was observed that the mechanical properties of the AlSi10Mg alloy increased significantly with the addition of 0.2 % Zr and 0.5 % V. Moreover, 64 hours aged 0.2 % Zr and 0.5 % V containing alloy, exhibited yield and tensile strengths of 212 and 250 MPa, respectively. Keywords: Al-Si alloys, Casting, Aging, Microstructure, Mechanical properties