Effect of IRON Removal on the Structure and Mecahnical Properties of Aluminium-Silicon Alloys
Keywords:
Micro Additives; Microstructure; Hardness; Strength; CompositionAbstract
The research work examined the effect of the removal of iron from aluminium-silicon alloys using dopants on the structure and mechanical properties. Manganese, cobalt and molybdenum were used as the modifying elements. The as-cast Al - Si alloys were analyzed for iron content using Atomic Absorption Spectrometer (AAS) technique. The dopants or modifying elements were added as micro additives at various compositions to the percentage of iron present in the master alloys. The modified alloys were produced by melting a calculated mass of the master alloys and adding the dopants in the ratios of 1:1, 2:1, 3:1 and 4.1 to the percentage of iron in the Al - Si alloy. The properties tested were ultimate tensile strength, percentage elongation, hardness and microstructure. The result of the chemical analysis of the alloys indicated that the dopants were able to reduce the percentage of iron in the alloys. On addition of 5.4%Co iron was reduced from 1.8% to 0.42%, which is far less than the critical iron level of 0.78%. The mechanical tests showed an improvement with the highest values achieved by the addition of 5.4%Co. The improvement in the microstructure is also shown in plates 1-8.
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