Effect of Al 2 Ca on Oxidation Resistance and Tensile Property of Al-5Mg Alloy

Abstract

The effect of Al 2 Ca on the oxidation resistance and tensile property of Al-5Mg alloys was investigated. According to the TGA (Thermogravimetric analysis) result at 550 o C after 24hrs, the Al-5Mg alloy showed parabolic behavior with weight gain. On the other hand, there was almost no difference in the weight changes of the Al 2 Ca added Al-5Mg alloys during the oxidation. It was thought that the improvement of oxidation resistance in Al 2 Ca added Al-5Mg alloys might be due to the formation of a protective oxide layer with CaO and MgO on the surface. The microstructures of the alloys showed grain refinement with an increasing Al 2 Ca content. From the tensile test, the yield strength of the alloys were improved with an increasing Al 2 Ca content. The 0.07 mass%Al 2 Ca added Al-5Mg alloy showed similar elongation and increased strength, simultaneously. It was considered that the addi-tion of Al 2 Ca, which was superior in the oxidation resistance of Al, reduced the formation of Mg oxides and inclusions during the alloying. This, partly led to the improvement of tensile properties.