Si含量对挤压铸造Al-5.0Cu-0.6Mn-0.7Fe合金显微组织和力学性能的影响

发布时间：2018-05-26 22:13

本文选题：Si + Al-Cu合金　；参考：《中国有色金属学报》2015年11期

【摘要】：采用拉伸性能和硬度测试、光学显微镜、扫描电镜和X射线衍射仪等手段研究不同Si含量对挤压铸造Al-5.0Cu-0.6Mn-0.7Fe合金显微组织和力学性能的影响。结果表明:当挤压压力为0时,随着Si含量的增加,凝固后期形成的富铁相阻止液相补缩,形成缩松组织,导致合金的抗拉强度、屈服强度和伸长率都下降;当挤压压力为75MPa时,随着Si含量增加,缩松组织消失,虽然细小和分散的α-Al15(Fe Mn)3(Si Cu)2相和Al2Cu相数量增多,但Al6(Fe Mn Cu)相消失,有利于晶界强化和阻止裂纹的扩展,使得合金的抗拉强度和屈服强度增加;虽然富铁相数量的增加使得合金伸长率降低,但挤压铸造工艺减缓了伸长率降低的趋势。当挤压压力为75 MPa和Si含量为1.1%(质量分数)时,合金的综合力学性能最好,其抗拉强度为232 MPa,屈服强度为118 MPa,伸长率为12.4%。
[Abstract]:The effects of Si content on the microstructure and mechanical properties of squeeze casting Al-5.0Cu-0.6Mn-0.7Fe alloy were studied by means of tensile and hardness tests, optical microscope, scanning electron microscope and X-ray diffraction. The results show that when the extrusion pressure is 0, with the increase of Si content, the rich iron phase formed at the later stage of solidification prevents the liquid phase from feeding and forms the shrinkage structure, which leads to the decrease of the tensile strength, yield strength and elongation of the alloy. When the extrusion pressure is 75MPa, the shrinkage microstructure disappears with the increase of Si content. Although the number of fine and dispersed 伪 -Al15Fe Mn)3(Si Cu)2 and Al2Cu phases increases, the Al6(Fe mn Cu) phase disappears, which is conducive to grain boundary strengthening and preventing crack propagation. The tensile strength and yield strength of the alloy increased, although the elongation of the alloy decreased with the increase of the amount of rich iron phase, the trend of elongation decrease was slowed down by squeeze casting process. When the extrusion pressure is 75 MPa and the Si content is 1.1% (mass fraction), the comprehensive mechanical properties of the alloy are the best, the tensile strength is 232 MPA, the yield strength is 118 MPA, and the elongation is 12.4 MPA.
【作者单位】：华南理工大学机械与汽车工程学院;
【基金】：GD-NSFC联合基金资助项目(U1034001) 国家自然科学基金资助项目(51374110) 教育部博士点基金资助项目(20120172110045) 广东省自然科学基金研究团队项目(015A030312003)
【分类号】：TG146.21

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