压力对A380铝合金的铸造组织和力学性能的影响

发布时间：2018-03-21 21:31

本文选题：A铝合金　切入点：挤压铸造　出处：《工程科学学报》2017年07期 　论文类型：期刊论文

【摘要】：对A380铝合金进行了挤压铸造成型和传统重力铸造成型,并制得试样.采用偏光显微镜、扫描电镜、定量金相分析、拉伸性能测试等手段,研究在不同压力下挤压铸造A380铝合金的铸造组织和力学性能.结果表明:当压力在0~75 MPa范围内时,随着压力的增加,一次枝晶臂尺寸和气孔率得到大幅下降,共晶组织体积分数增加;二次枝晶臂间距减小;针状富铁β-Al_5FeSi相尺寸大幅度减小,同时有部分汉字状α-Al8(Fe,Mn)_3Si_2相生成.当压力在75~100 MPa范围内时,压力继续增加对合金组织细化、第二相形貌改善和力学性能提高的作用不明显.挤压铸造试件与重力铸造试件相比,气孔率减小,显微组织细化,力学性能显著提高.当压力为75 MPa时,挤压铸造A380铝合金的铸态抗拉强度和伸长率分别比重力铸造提高19%和65%.
[Abstract]:The A380 aluminum alloy was molded by squeeze casting and traditional gravity casting. The samples were obtained by means of polarizing microscope, scanning electron microscope, quantitative metallographic analysis, tensile test and so on. The casting microstructure and mechanical properties of A380 aluminum alloy by squeeze casting under different pressures were studied. The results showed that the size and porosity of primary dendrite arm decreased significantly with the increase of pressure when the pressure was in the range of 0 ~ 75 MPa. The volume fraction of eutectic structure increased; the secondary dendritic arm spacing decreased; the size of acicular Fe-rich 尾 -Al-Al5FeSi phase decreased significantly, and some Chinese character 伪 -Al8FeMnSi2 phases were formed. When the pressure was in the range of 7510 MPa, the microstructure of the alloy was further refined by increasing the pressure. The effect of improving the morphology and mechanical properties of the second phase is not obvious. Compared with the gravity casting specimens, the porosity of the squeeze casting specimens is reduced, the microstructure is refined, and the mechanical properties are improved significantly. When the pressure is 75 MPa, The tensile strength and elongation of cast A380 aluminum alloy increased by 19% and 65% respectively compared with gravity casting.
【作者单位】：北京交通大学机械与电子控制工程学院;杭州海康威视数字技术有限公司;一汽铸造有限公司有色铸造分公司;
【基金】：国家863项目(2014AA041804)
【分类号】：TG249.2

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