摘要
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 microstructure and mechanical properties of Mg-8Li-3Al-Y alloys after multi-hot rolling at 280 ℃ with different reduction rates and subsequent annealing were studied with methods of optical microscope（ OM）,mechanical property testing and fracture morphology analysis of scanning electron microscope（ SEM）. The results showed that α phase transformed into fiber texture along the rolling direction with 80% hot rolling reduction,and the microstructure was evidently refined after hot-rolling. After 350 ℃ × 2 h annealing,most of α phases transformed into bamboo-like microstructure with some globular-like α phases. The tensile strength,elongation and microhardness of Mg-8Li-3Al-Y alloy with 80% hot rolling reduction were 195. 75 × 106 Pa,18% and HV74. 84,respectively. After 350 ℃ × 2 h annealing,they turned into 188. 09 × 106 Pa,34% and HV66. 01,respectively. Furthermore,it could be concluded that the tensile failure mechanism of hot-rolled Mg-8Li-3Al-Y alloy with 80% reduction in thickness was quasi-cleavage fracture and became cleavage and dimple facture mode after annealing. These indicated that annealing treatment could improve the plasticity of the alloy sharply with small decrease of strength and hardness.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2015年第7期577-582,共6页
Chinese Journal of Rare Metals
基金
国家科技部火炬计划项目(2011HG30513)资助
