Microstructure and mechanical properties of conventional cast and rheocast Mg-Sn based alloys

Poddar, Palash and Sahoo, K L (2012) Microstructure and mechanical properties of conventional cast and rheocast Mg-Sn based alloys. Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 556 (IF-2.003). pp. 891-905.

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Abstract

In the present study, microstructure and mechanical properties of conventional cast and rheocast Mg-Sn alloy systems were investigated. The microstructure of conven-tional cast Mg-5%Sn and Mg-8%Sn alloys showed different phases, such as primary alpha-Mg, beta-Mg2Sn phase that precipitates at the grain boundary, and eutectic alpha-Mg, a dark area surrounding the precipitate phase. With the addition of misch metal in Mg-5%Sn alloy the refinement of microstructure was observed and also the interdendritic second phase changed from rod/irregular shaped to rod and feathery shaped. In Mg-8%Sn-3%Al-1%Si alloy, alpha-Mg, Mg2Sn, Mg17Al12 and Mg2Si phases were observed. With the addition of Al-Sc master alloy in Mg-8%Sn alloy the matrix grain size became finer. The rheocast microstructures showed that the primary alpha-Mg phase is non-dendritic and globular shaped. Solution heat treatment at 520 deg-rees C for 48-72 h leads to complete dissolution of Mg2Sn intermetallic in Mg-Sn alloys. During ageing at 200 degr-ees C discontinuous precipitates were formed at the grain boundaries in the initial stage and later continuous preci-pitates were occurred in the remaining regions. Hardness values were significantly improved after 100 h of aging for all the alloys compared to as-cast alloys. The tensile properties of rheocast alloys were significantly higher than the conventional cast alloys.

Item Type:Article
Official URL/DOI:http://www.sciencedirect.com/science/article/pii/S...
Uncontrolled Keywords:Al-SI alloy; Magnesium alloy; Discontinuous precipitation; creep-behavior; Driving force
Divisions:Material Science and Technology
ID Code:6371
Deposited By:Dr. A K Sahu
Deposited On:28 Feb 2013 13:21
Last Modified:05 Nov 2013 10:20
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