During previous research on alloys of the Al-Si-Cu-Mg system it was proven that adding transition metals, for instance Zr and Mo, increase mechanical properties, for example ultimate tensile strength and yield stress. That is why we focused on the effects of the addition of those two metals on the mechanical properties of the commercially-available cast Al alloy AlSi10MnMg (Silafont-36, from Rheinfelden). Castings from this alloy are made in the process of high pressure die casting, most frequently in the automobile and aerospace industry.
With the purpose of researching the addition of Zr and/or Mo on mechanical properties of the casting alloy Silafont-36 we created five new experimental alloys, with different additions of Zr and/or Mo. We were determining the effect of additional elements on the microstructure, which we monitored with an optical as well as an electron microscope. With the help of EDS analysis, we carried out the qualitative as well as quantitative phase analysis. Measuring the Vickers hardness, we came to the conclusion that hardness with a higher addition of new alloy elements increases (by almost 30 %), the addition of Mo having a big positive impact. We also carried out tensile testing. We compared properties, for example tensile strength, yield strength and breaking elongation with the starting alloy and revealed the optimal addition of Zr and Mo.
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