中文摘要：

研究了添加铍对镁合金AZ91D的阻燃性以及混合稀土对其组织与力学性能的影响。结果表明,铍（Be）可以有效地提高镁合金的起燃温度,含0.3wt%Be的镁合金的起燃温度提高近300℃,可直接暴露在大气中熔炼。稀土可抑制镁合金AZ91D非平衡结晶的进行,同时也抑制Mg17Al12相的析出,强化了基体;另外花瓣状和短杆状Al4RE相可阻止裂纹的形成,增大合金的断裂抗力,从而使合金的室温抗拉强度在固溶态和时效态下均提高20%;硬度在铸态下提高20%,在时效态下提高30%。由于Al4RE相热稳定性高,使高温抗拉强度在铸态下提高50%,在时效态下提高20%;伸长率在铸态和时效态下均提高100%。

英文摘要：

The effects of Be addition on ignition-proof property and mischmetall addition on microstructure and mechanical properties of AZ91D- 0.3Be-RE magnesium alloy were studied. The results show that Be addition can effectively increase ignition temperature. By doping 0.3 % Be to magnesium alloy, the ignition temperature increases about 300℃ and the alloy can be melted in air. Rare-earth inhibits non-equilibrium solidification of magnesium alloy and precipitation of Mg17 Al12 phase and strengthens the matrix. Petal-like and short-bar-like Al4RE phase prevents the crack forming and increases the fracture resistance of the alloy. The room-temperature tensile strength of both the solid-solutioned and aged alloy is increased by 20%. The hardness of the as-cast alloy is increased by 20% and of the aged alloy by 30% . For the high thermal stability of Al4RE phase, the high-temperature tensile strength of the as-cast alloy is increased by 50% and of the aged alloy by 30%. The elongation of both the as-cast and aged alloy is increased by 100% .