铸造Al-Si合金表面粗糙度的高温演变机制  

Evolution mechanism of cast Al-Si alloy surface roughness at high temperature

作　　者：李阳 李建平[1] 刘磊 郭永春[1] 保彤 高宇 龚文健 王缘 LI Yang;LI Jian-ping;LIU Lei;GUO Yong-chun;BAO Tong;GAO Yu;GONG Wen-jian;WANG Yuan(School of Materials and Chemical Engineering,Xi’an Technological University,Xi’an 710021,China)

机构地区：[1]西安工业大学材料与化工学院,西安710021

出　　处：《中国有色金属学报》2021年第8期2115-2124,共10页The Chinese Journal of Nonferrous Metals

基　　金：陕西省科学技术基金资助项目(2020JQ-808);陕西省教育基金资助项目(19JK0400,19JK0402);中国北方发动机研究所资助项目(DLBF2018-KY-JS-066-J);西安工业大学校长基金资助项目(XAGDXJJ17008)。

摘　　要：对经过T6处理的两种铸造Al-Si合金(Si含量为12%和18%,质量分数)进行不同温度(250、350、450、550℃)、时间2 h的热暴露试验。采用表面粗糙度仪、金相显微镜、扫描电子显微镜、专业型同步热分析仪等测试方法相互结合,对两种Al-Si合金在高温热暴露条件下表面状态的变化进行研究。结果表明:Al-x%Si二元合金的粗糙度变化基本遵循R_(a,T6)>R_(a,thermal exposure)>R_(a,as-cast)的规律;随着热暴露温度的升高,Al-12%Si粗糙度呈现先降低后升高的趋势,Al-18%Si粗糙度呈现不断升高的趋势;合金表面粗糙度的变化与热暴露试验过程中的Al/Si相界开裂和稀土相的析出有关;对比粗糙度及表面微观形貌变化发现:Al-18%Si比Al-12%Si具有更加优良的高温稳定性,即在较低温度下,随着Si含量的增加,Al-x%Si合金发生开裂的趋势逐渐降低。Thermal exposure tests were performed on two cast Al-Si alloys by T6 heat treatment at different temperatures(250,350,450 and 550℃)for 2 h.The surface roughness tester,metallographic microscope,scanning electron microscope,simultaneous thermal analyzer and other testing methods were used to study the change of the surface state of two Al-Si alloys under high temperature thermal exposure conditions.The results show that the roughness change of Al-x%Si binary alloy basically follows the law of Ra,T6>Ra,thermal exposure>Ra,as-cast;with the increase of thermal exposure temperature,the roughness of Al-12%Si tends to decrease first and then increases,while that of Al-18%Si tends to increase continuously.The change of alloy surface roughness is related to Al/Si phase boundary cracking and precipitation of rare earth phase during thermal exposure test.By comparing the roughness and phase changes,it is found that Al-18%Si has better high temperature stability than Al-12%Si.That is to say,at lower temperature,with the increase of Si content,the tendency of Al-x%Si cracking gradually decreases.

关 键 词：AL-SI合金 粗糙度 微观组织 热暴露 

分 类 号：TG146.2[一般工业技术—材料科学与工程]