HOT TEARING TENDENCY AND TENSILE PROPERTY CHANGE OF Ni AND Cu ADDED A356 CASTING ALLOY

摘要

Aluminium-Silicon alloys are the most preferred choice of casting alloys due to their excellent properties mainly owing its features to the presence of silicon. A356 has 7 wt% Si and 0.2 wt% Mg. This alloy suffers high temperature mechanical properties. Therefore, the addition of minor ratios of different alloying elements has been a long going investigation by many researchers, In this work, mechanical property change and hot tearing characteristics of Ni and Cu added A356 alloy was investigated. Ni was added up to 0.2 wt% while Cu addition was increased up to 2 wt%. Moreover, the relation of the amount of dissolved hydrogen in the liquid aluminium with respect temperature was evaluated by means of porosity formation. It has also been determined by Dispinar and Campbell that the amount of bifilms determine the mechanical properties of cast aluminium alloys. The quantification of bifilms were carried out by using Reduced Pressure Test. The size and distribution of pores on the cross section of vacuum solidified samples were measured. Bifilm index change with alloying element additions were recorded.