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研究了Mg-8Li-3Al-Y合金在温度为280℃时多道次不同压下率的轧制变形以及轧后热处理,通过金相(OM)显微组织观察、力学性能测试、扫描电子显微镜(SEM)断口形貌分析的方法,获得此合金不同压下率及轧后热处理的组织性能变化规律。研究结果表明:随着压下率的增加,轧后α相沿轧制方向明显延长,晶粒明显细化,在压下率为80%时,形成了强烈的纤维组织。热轧板材经350℃×2 h退火处理后,大部分α相形成了“竹节状”组织,并有一定数量的球状α相。压下率为80%热轧板材的抗拉强度、延伸率以及维氏硬度分别为195.75×106Pa,18%和HV74.84,经退火后热轧板材的抗拉强度、延伸率、维氏硬度分别为188.09×106Pa,34%和HV66.01;压下率为80%的热轧Mg-8Li-3Al-Y合金板材的拉伸断裂方式为准解理断裂,退火后合金板材的拉伸断裂方式为解理+韧窝混合断裂。这说明轧后热处理可以使合金在小幅度地降低硬度和强度的情况下,大幅度地提高合金的塑性。
The rolling deformation and post-rolling heat treatment of Mg-8Li-3Al-Y alloy at 280 ℃ were studied. The microstructure of the Mg-8Li-3Al-Y alloy was investigated by OM microstructure, mechanical properties, scanning electron microscopy (SEM) fracture surface morphology analysis of the alloy obtained under different reduction rates and the rolling heat treatment after the change of the microstructure and properties. The results show that with the increase of the reduction rate, the α phase after rolling significantly prolongs along the rolling direction, and the grain is obviously refined. When the reduction rate is 80%, the strong fiber structure is formed. After hot-rolled sheet annealed at 350 ℃ for 2 h, most of the α phase formed a “bamboo-like” structure, and a certain amount of spherical α phase. The tensile strength, elongation and Vickers hardness of hot rolled sheet with the reduction of 80% were 195.75 × 106Pa, 18% and HV74.84, respectively. The tensile strength, elongation, Vickers hardness Respectively 188.09 × 106Pa, 34% and HV66.01; tensile fracture mode of hot-rolled Mg-8Li-3Al-Y alloy sheet with 80% reduction rate is quasi-cleavage fracture, tensile fracture of alloy sheet after annealing Way for cleavage + dimple mixed fracture. This shows that after rolling heat treatment can make the alloy in a small decrease in hardness and strength of the case, a substantial increase in plasticity of the alloy.