摘要
对3种低硅铸造铝合金和A356在300℃进行0~200 h的热暴露试验,测试了合金室温拉伸性能随热暴露时间的变化规律。采用金相显微镜(OM)、扫描电子显微镜(SEM)观察金相组织及断口形貌;借助扫描电镜的能谱分析(EDS)测定不同相的元素分布,并观察热暴露前后组织中元素分布情况,探究热暴露时间和Cu元素含量对合金高温稳定性的影响。结果表明,3种低硅铸造铝合金和A356铝合金在热暴露25 h后抗拉强度分别下降了56%、55%、55%和58%,而且随着热暴露时间的增加,抗拉强度持续下降。对0.3%Cu实验铝合金研究发现,300℃热暴露会造成合金组织中Si、Mg、Cu主要元素偏析,造成基体中强化相分布不均匀。
Three low silicon cast aluminium alloys and A356 were exposed to a baking oven of 300 ℃ for 0-200 h, and the variation of the room temperature tensile properties of these alloys with the thermal exposure time was tested. The metallographic structure and fracture morphology were observed by OM and SEM;the element distribution in different phases was determined by EDS, and the element distribution in the microstructure before and after thermal exposure was observed;the effect of thermal exposure time and Cu content on the high temperature stability of the alloy was explored. The results show that the tensile strengths of three low silicon cast aluminium alloys and A356 aluminium alloy decrease sharply by 56%, 55%, 55% and 58%, respectively, after 25 h of thermal exposure, and the tensile strength decreases continuously with an increase in thermal exposure time. The study on 0.3% Cu-containing aluminium alloy shows that thermal exposure at 300 ℃ will cause segregation of Si, Mg and Cu elements in the alloy structure, resulting in uneven distribution of strengthening phases in the matrix.
作者
程腾飞
曾瑞祥
赵天天
杨弋涛
CHENG Teng-fei;ZENG Rui-xiang;ZHAO Tian-tian;YANG Yi-tao(School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China)
出处
《铸造》
CAS
北大核心
2019年第11期1249-1254,共6页
Foundry
关键词
AL-SI合金
热暴露
高温稳定性
拉伸性能
显微组织
Al-Si alloy
thermal exposure
high temperature stability
tensile properties
microstructure
