La对定向凝固Al-4.5%Cu合金热疲劳性能的影响  

Effect of La on Thermal Fatigue Property of Unidirectional Solidification of Al-4.5%Cu Alloy

作　　者：司乃潮[1] 华雄飞[1] 司松海 袁婷婷[1] 李达云[1] 

机构地区：[1]江苏大学材料科学与工程学院,江苏镇江212013 [2]镇江忆诺唯记忆合金有限公司,江苏镇江212009

出　　处：《铸造》2009年第3期262-265,共4页Foundry

基　　金：江苏省科技型中小企业技术创新资金项目(BC2007144);镇江市工业科技攻关项目(GY2007023);江苏大学‘科技创新团队’资助

摘　　要：采用自约束热疲劳试验机,对加入La的定向凝固Al-4.5%Cu合金进行热疲劳性能试验。结果表明,加入适量La对定向凝固Al-4.5%Cu合金的热疲劳性能有不同程度提高,其中,加入0.3%La的热疲劳试样疲劳性能较佳,达到热疲劳裂纹萌生所需的热疲劳循环次数最多;通过热疲劳循环次数与主裂纹长度的动态关系图,发现热疲劳裂纹的扩展有别于一般由机械交变载荷造成的常温疲劳,呈现先快后慢,阶段性扩展。The thermal fatigue property of unidirectional solidified AI-4.5%Cu alloys with La was tested on self-restrict thermal fatigue experimental machine. The results show that the suitable addition of La has obviously improved the thermal fatigue property of unidirectional solidification of AI-4.5%Cu alloys. The thermal fatigue property of alloys with 0.3%La is quite fine, and the initiation of crack reaches the highest thermal fatigue cycle index. Dynamic relationship diagram of thermal fatigue cycle index and main crack length show that the propagation of thermal fatigue crack is fast at first and then slow, which is different from the fatigue caused by mechanical alternate loads at normal temperature.

关 键 词：定向凝固 AL-4.5%CU合金 热疲劳 热疲劳裂纹的萌生与扩展 

分 类 号：TG111.4[金属学及工艺—物理冶金]