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Microstructures and Mechanical Properties of Diecast 0.7wt% CaO added Eco-Mg Parts  

Seo, Jung-Ho (Foundry Tech. Ctr., Korea Institute of Industrial Technology)
Lim, Hyun-Kyu (Foundry Tech. Ctr., Korea Institute of Industrial Technology)
Kim, Shae-K. (Foundry Tech. Ctr., Korea Institute of Industrial Technology)
Publication Information
Journal of Korea Foundry Society / v.30, no.6, 2010 , pp. 224-230 More about this Journal
Abstract
To prevent oxidation of Mg melt, $SF_6$ gas has been generally used for Mg alloys during melting and casting as a cover gas. The use of $SF_6$ gas, however, will be restricted owing to its crucial impact on global warming. Non-$SF_6$ process during melting and casting in diecasting industry has been proved with Eco-Mg alloys by a simple addition of small amount of CaO into Mg alloys. This paper shows non-$SF_6$ diecasting procedures for 0.7wt% CaO added AZ91D Eco-Mg alloys. Cold-chamber diecasting was performed under $CO_2$ atmosphere without $SF_6$ gas. An increment of mechanical properties, especially strength and ductility of Eco-Mg alloys is, in part, due to high-quality melt, refined grain size and $Al_2Ca$ second phase strengthening. Microstructures and mechanical properties of 0.7wt% CaO added AZ91D Eco-Mg alloys are evaluated in comparison with those of conventional AZ91D Mg alloy.
Keywords
AZ91D; CaO; Eco-Mg; Non-$SF_6$ process; Strength; Elongation;
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