Mg-10Y-2.45Zn-1Ca-0.37Al合金的组织演变及力学行为

Microstructure Evolution and Mechanical Behavior of Mg-10Y-2.45Zn-1Ca-0.37Al Alloy

摘要:

本文通过磁悬浮熔炼铜模吸铸工艺制备了Mg-10Y-2.45Zn和Mg-10Y-2.45Zn-1Ca-0.37Al两种合金,考察复合添加高含量Ca及少量Al合金元素对铸态Mg-10Y-2.45Zn合金中LPSO相形成的影响及其在固溶热处理及高温高应力下的组织演变规律及力学行为变化。结果表明,铸态下高含量Ca及少量Al参与了18R LPSO的大量形成且出现大量18R LPSO相分层界面；在高温下,不同于Mg-10Y-2.45Zn合金,Mg-10Y-2.45Zn-1Ca-0.37Al中的18R LPSO大量溶解,并在晶界处合并长大、a-Mg晶粒粗化；在高温大塑性变形条件下,大块状18R LPSO扭折、分层或破碎,18R LPSO相界附近发生动态再结晶和α-Mg基体内析出大量细小棒状14H LPSO相强化了合金。

Abstract:

Mg-10Y-2.45Znand Mg-10Y-2.45Zn-1Ca-0.37Al alloys were fabricated by magnetic levitation induction smelting coupled with copper-mould suction casting technique. The compound effect of high content Ca and small amount of Al alloying element addition on the formation of LPSO phase in as-cast Mg-10Y-2.45Zn alloy and the microstructure evolution and mechanical behavior under high temperature and high stress were investigated. The results showed that high content of Ca and a small amount of Al were involved in the formation of massive 18R LPSO and a large number of 18R LPSO phase delamination interface emerged under the as-cast condition. At high temperature, unlike the Mg-10Y-2.45Zn alloy, a large number of 18R LPSO phases dissolved and grew at the grain boundaries of Mg-10Y-2.45Zn-1Ca-0.37Al, the size of α-Mg grains coarsen. At high temperature and high plastic deformation, massive 18R LPSO kinked, delamination or crushed, dynamic recrystallization occured at the vicinity of the 18R LPSO phase boundary and a large number of fine rod-like 14H LPSO phases precipitatied in α-Mg matrix conspire to strengthen the alloy.