摘要
对不同工艺处理的铝硅合金ZAlSi7Cu4,用自约束型热疲劳试验机进行25～350℃的热循环试验,研究了不同处理工艺对该材料热疲劳性能的影响。通过光学显微镜和扫描电镜观察了试样的热疲劳裂纹形貌,分析了合金热疲劳损伤机制。结果表明,在350℃下,经过T6处理的该材料相对其他处理工艺具有更好的热疲劳性能。颗粒的位向会影响裂纹的扩展路径;氧化孔洞的曲率半径较大时可减缓裂纹在孔洞边缘的萌生扩展;材料在T6、铸态淬火+时效、铸态3种处理工艺下的试样表面硬度随着热循环次数的增加总体呈现下降趋势,而在裂纹萌生前的一段周次内,T6和铸淬+时效试样的硬度均微弱回升。
The thermal cycling curves of ZAlSi7Cu4 treated by different heat treatment were drawn on a self-restrict thermal fatigue experimental machine at 25～350 ℃ to understand the effect of different heat treatment processes on the thermal fatigue behavior of the alloy.The thermal fatigue mechanism was analyzed by observing thermal fatigue crack morphology of the alloy samples with the help of OM（optical microscope） and SEM（scanning electron microscope）.The results show that the sample with T6 heat treatment is superior to one treated by other process in thermal fatigue resistance at 350 ℃.The expansion path of the crack can be controlled by the location of the grain,and the crack generation in the edge of the cavern can be slowed down with a higher curvature radius.The micro-hardness of the sample surface is decreased with the increase of the thermal cycle number,however,the microhardness of the samples treated by T6 and as-cast quenching plus aging has a slightly ascension in the period before the initiation of the crack.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2012年第4期381-385,共5页
Special Casting & Nonferrous Alloys
基金
科技部科技型中小企业技术创新基金项目(09C26279200863)
江苏大学"科技创新团队"资助项目
