مقايسه سياليت، ريز ساختار و خواص مكانيكي آلياژهاي آلومينيم اوليه و ثانويه

Comparison of Fluidity, Mechanical Properties and Microstructure of Primary and Secondary Aluminum Alloys

Fluidity, microstructure and mechanical properties of primary and secondary aluminum alloys were investigated. Spiral fluidity test of a 356 secondary aluminum alloy, made with 10-15 percent scrap, showed no clear reduction in fluidity in comparison to primary ingot from the same alloy. Similar test for comparing the fluidity of primary and secondary ingots of 413 aluminum alloy, while latter was made with around 50 percent from scrap, showed about 10-15 percent decrement. No clear difference was noticed between the UTS of castings made from 356 primary and secondary A1 alloy. This seems to be the result of good melt treatment and also the presence of Zn and Cu in solid solution. This was not the case in 413 A1 alloy and the secondary alloy showed some reduction in tensile tests. Microstructures of castings made from 413 secondary alloy showed typical inclusions and intermetalics. In LM4 secondary alloy tensile tests showed weaker results in comparison with primary ingots again possibly as a result of presence of oxide film and Fe rich intermetalics in microstructures.