摘要
采用拉伸性能测试、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等研究Fe含量对挤压铸造Al-Cu合金组织演变及高温力学性能影响。结果表明:随着Fe含量的增大,铝铜合金的常温和高温性能急剧下降,这主要是由于针状富铁相增多,同时铝铜合金基体中强化相减少。而耐热富铁相可以一定程度上阻碍晶界高温滑移,Fe含量对合金高温力学性能的影响没有常温性能那么敏感。挤压压力可以显著提高合金的高温性能,尤其是合金的伸长率,但与常温力学性能相比,挤压压力对高温力学性能的提升幅度下降。同时,挤压铸造铝铜合金的高温伸长率在Fe含量为0.5%(质量分数)的附近存在一个峰值。这主要是由于挤压压力下合金致密,富铁相尺寸变得细小,针状富铁相大幅减少,同时晶粒细化导致高温下晶界弱化加剧。
The effects of Fe content on the evolution of microstructure and elevated-temperature mechanical properties of squeeze cast Al-Cu alloys were studied by tensile test, scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results show that the room temperature and elevated-temperature mechanical properties decrease with increasing Fe content in Al-Cu cast alloys, which attribute to the increase of volume fraction of needle-like iron-rich intermetallics and the decrease of volume fraction of precipitation particles in α(Al) matrix. The heat-resistant iron-rich intermetallics phases around the grain boundary can prevent the sliding of grain boundary at elevated temperature. As a result, the effect of Fe content on elevated-temperature mechanical properties is less sensitive than room-temperature mechanical properties. The applied pressure improves the elevated temperature mechanical properties, especially the elongation. However, the increased range of elevated temperature mechanical properties resulted by applied pressure decreases compared to the room temperature mechanical properties, and there is a peak value of elongation at elevated temperature for the squeeze cast alloys with Fe content of 0.5%(mass fraction). The results attribute to the high dense-component of squeeze cast alloys, the refinement of iron-rich intermetallics, the decrease of needle-like iron-rich intermetallics, and the refinement of grain size which leaded to the weakness of grain boundary at elevated temperature.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2017年第5期885-893,共9页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(51374110)
广东省自然科学基金团队项目(2005A030312003)
贵州大学引进人才科研基金资助项目(201440)
国家金属材料近净成形工程技术研究中心开放基金项目(2015009)~~
关键词
铝铜合金
富铁相
高温力学性能
挤压铸造
Al-Cu alloys
iron-rich intermetallic
elevated-temperature mechanical properties
squeeze casting
