摘要
研究快速冷却条件下不同稀土镧含量(w(La)分别为0,0.3%,0.6%,0.9%,1.2%)的AZ91镁合金的显微组织及相组成,并测试了其力学性能。试验结果表明,经XRD物相分析得知AZ91镁合金是由α-Mg和β-Mg17Al12组成,当向其添加不同含量的La时,会有针状Al11La3析出,且β相数量减少。随着镧含量增加,合金晶粒尺寸由80.29μm减小到66.88μm,细化幅度达到16.7%。稀土La的加入可提高合金的硬度、抗拉强度、伸长率,这与晶粒细化、β相数量的改变以及弥散强化有关。试验中,力学性能最佳的是AZ91+0.9%La合金,其硬度值为84.18 HV,室温抗拉强度为237 N/mm2,伸长率为4.46%;220℃高温抗拉强度为154 N/mm2,伸长率为8.6%。
The microstructure, phase composition and mechanical properties of AZ91 （w （La） = 0,0.3 % ,0.6%, 0.9 %, 1.2% ） （ mass fraction ） magnesium alloy were studied with different La content under rapid cooling condition. The experimental results show that the phase composition of AZ91 is α-Mg and β-Mg17Al12 by XRD analysis. With the increase of La content,needle-shaped AIII La3 produces, 13-phase reduces, the grain size of AZ91 reduces from 80.29μm （0%wt La） to 66.88 μm （0.9%wt La）,and the reduced rate is 16.7%. The addition of rare earth element La improves the hardness, tensile strength and elongation rate,which is relevant with the mechanism of grain refinement, β-phase content difference and dispersion strengthening effect. The sample with best mechanical properties in this research is AZ91 ＋ 0.9% La alloy, with hardness value 84.18 Hv, tensile strength 237 N/mm^2 and elongation rate 4.46% at the room temperature,as well as tensile strength 154 N/mm^2 and elongation rate 8.6% at 220℃.
出处
《轻合金加工技术》
CAS
北大核心
2015年第4期62-67,共6页
Light Alloy Fabrication Technology
关键词
镁合金
快速冷却
稀土
显微组织
力学性能
magnesium alloy
rapid cooling
rare earth
microstructure
mechanical properties
作者简介
董方（1964-），男，内蒙古包头人，教授，主要从事钢铁冶金新工艺新技术方面的研究。
