| 摘要 |
Amagnesiumalloy for casting according to the present invention is characterized in that , when the entirety is taken as 100% by mass, it includes copper (Cu) in an amount of from 1% by mass or more to 5% by mass or less, calcium (Ca) in an amount of from 0.1% by mass or more to 5% by mass or less, tin (Sn) in an amount of from 0.1 or more to 3 or less by mass ratio with respect to the Ca (Sn/Ca); and the balance comprising magnesium (Mg) and inevitable impurities. By means of including Cu, Ca and Sn, crystallized substances of Mg-Ca-Sn compounds crystallize in crystalline grain boundaries between Mg crystalline grains as network shapes (three-dimensionally mesh shapes), along with Mg-Cu compounds. By means of the three-dimensionally mesh constructions, grain-boundary sliding, which becomes active especially when becoming high temperature, is suppressed, and thereby high-temperature strength and creep resistance at high temperature improve. Moreover, since Sn forms compounds with Ca preferentially, it influence less on the heat conductivity, compared with the other additive elements.
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