铝合金中厚板焊接接头显微组织及其疲劳损伤  

Microstructure and fatigue damage of welded joint of aluminum alloy medium plate

作　　者：范聪 杨尚磊[1] 白易山 朱敏琪 FAN Cong;YANG Shanglei;BAI Yishan;ZHU Minqi(School of Materials Engineering,Shanghai University of Engineering Science,Shanghai 201620,China)

机构地区：[1]上海工程技术大学材料工程学院,上海201620

出　　处：《理化检验（物理分册）》2022年第2期30-35,共6页Physical Testing and Chemical Analysis(Part A:Physical Testing)

基　　金：国家自然科学基金资助项目(51971129);上海市自然科学基金资助项目(19ZR1421200)。

摘　　要：采用熔化极惰性气体保护焊焊接了厚度为12 mm的7N01-T5铝合金板,分析了焊接接头的显微组织,并对焊接接头进行了拉伸及疲劳试验。用能谱分析法确定了疲劳条带间的二次相为含Fe相,提出了一种二次相所致的疲劳微裂纹萌生模型,解释了在疲劳条带间第二相处的微裂纹萌生原因。结果表明:焊接接头的抗拉强度为259 MPa,延伸率为11.4%,接头的拉伸断裂形式为韧性断裂和脆性断裂混合形式;二次相导致的微裂纹会加快疲劳裂纹的扩展速率。7 N01-T5 aluminum alloy plates with thickness of 12 mm were welded by MIG welding. The microstructure of the welded joints were analyzed, and the tensile and fatigue tests were carried out. The secondary phase between fatigue strips was determined to be Fe-containing by energy spectrum analysis. A fatigue micro-crack initiation model caused by secondary phase was proposed, and the causes of micro-crack initiation at the second phase between fatigue strips were explained. The results show that the tensile strength of the welded joint was 259 MPa and the elongation was 11.4%. The tensile fracture form of the joint was a mixture of ductile fracture and brittle fracture. The micro-cracks caused by secondary phase would accelerate the propagation rate of fatigue cracks.

关 键 词：铝合金 熔化极惰性气体保护焊 显微组织 疲劳性能 

分 类 号：TG453[金属学及工艺—焊接] TG115.5