激光表面熔凝处理过共晶Al-Si合金的疲劳裂纹扩展行为  

Fatigue crack growth behaviour of hypereutectic Al-Si alloy treated by laser surface melting

作　　者：张华顺[1] 王明星[1] 刘志勇[1] 刘忠侠[1] 翁永刚[1] 宋天福[1] 

机构地区：[1]郑州大学材料物理教育部重点实验室,河南郑州450052

出　　处：《轻合金加工技术》2007年第11期42-45,58,共5页Light Alloy Fabrication Technology

摘　　要：试验研究了Al-20%Si合金在激光表面熔凝处理后的显微组织特征及激光表面熔凝处理对合金疲劳裂纹扩展形为的影响。结果表明,激光表面熔凝处理使试验合金的显微组织得到了明显细化,熔凝层主要由细小的初生Si、-αAl及Al-Si共晶相组成,熔凝层的硬度显著提高;在应力比R为0.1和0.5的试验条件下,激光表面熔凝处理显著提高了试验合金的疲劳裂纹扩展抗力。The microstmcture characteristics and the fatigue crack growth behaviour of AL-20%Si alloy treated by laser surface melting were investigated. The results show that the microstructures of the laser-melted layer of the testing alloy are obviously refined, and that the hardness of the laser-melted zone is also increased. ＇lhe microstructure of the laser-melted layer mainly consists of fine primary Si particles,a-Al phase and Al-Si eutectic phase. The experinental results also show that laser surface melting treatment significantly increases the resistance of fatigue crack growth of the testing alloy at the testing conditions of stress ratio R = 0.1 and 0.5. K

关 键 词：激光表面熔凝 疲劳裂纹扩展 显微组织 

分 类 号：TG665[金属学及工艺—金属切削加工及机床]