摘要
通过光学显微镜(OM)、扫描电镜(SEM)等分析测试方法研究了机械振动对再生铸造铝合金的微观组织和力学性能的影响。结果表明:在未添加3%Al-3B的再生铸造铝合金凝固过程中施加机械振动使粗大枝晶破碎,初生α(Al)相趋于等轴晶,二次枝晶臂间距减小;在加入3%Al-3B的再生铝凝固过程中施加机械振动,能显著地细化合金中的组织并改善富铁相的形貌,使长针状的富铁相转变为短棒状或球状且均匀的分布于晶界处;同时增大振动频率还能较大幅度地改善再生铝合金的力学性能,当振动频率为40 Hz时,振动效果最佳,晶粒尺寸明显减小,由91μm减小到63μm,且二次枝晶臂间距最小,合金的室温抗拉强度和伸长率分别为171 MPa,4.74%,合金的强度和伸长率相对于无振动条件下的分别提高了约9.6%,34.6%,其合金力学性能最优。
The effect of mechanical vibration on microstructure and mechanical properties of recycled casting aluminum alloy was studied by optical microscopy （OM） and scanning electron microscopy （SEM）. The experiment results showed that mechanical vibra- tion could make the bulky dendrite break, and the primary phase α was transformed into isometric crystal and the secondary dendrite arm space of alloy decreased during the process of solidification of recycled cast aluminum alloy without addition of 3% Al-3B. The grain size of recycled aluminum alloy with addition of 3% Al-3B and morphology of β phase （A1SiFe） could be markedly improved through mechanical vibration in the process of solidification with the increase of vibration frequency, the morphology of β phase （A1SiFe） trans- formed from long needle-like into short rod-like which uniformly distributed in the grain boundary. The increase of mechanical vibration frequency could also strongly improve the mechanical properties of recycled casting aluminum alloy. When the frequency was 40 Hz, vibration was optimal, the grain size significantly decreased from 91 to 63 μm and the secondary dendrite arm space of alloy arrived at minimum, whose ultimate tensile strength and elongation were 171 MPa and 4.74% respectively, the values of tensile strength and e- longation of recycled casting aluminum alloy were increased by 9.6% and 34.6% respectively compared with that under vibration fre- quency of 0 Hz, and the mechanical properties was ultimate.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2014年第2期185-192,共8页
Chinese Journal of Rare Metals
基金
广东省科技厅产学研重大科技专项项目(2009A080205004)
广州有色金属研究院青年基金项目(2012B007)资助
关键词
再生铸造铝合金
机械振动
力学性能
recycled casting aluminum alloy
mechanical vibration
mechanical properties
