摘要
采用中频逆变直流点焊机进行7075铝合金点焊焊接试验,并对焊接接头的显微组织和力学性能进行研究.结果表明:焊接接头结构分为熔化区、部分熔化区和热影响区,其熔核的部分熔化区组织为柱状晶,熔化区组织为等轴晶,热影响区及母材仍保持轧制组织形态,而且焊接接头内存在枝晶偏析;7075铝合金点焊接头的熔核硬度较低;在所用的试验条件下,7075铝合金点焊接头均在界面断裂,断裂形式为准解理脆性断裂,且塑性、韧性较差,其原因在于焊接接头的强度低于母材,以及熔化区铝合金元素偏析严重.
The medium frequency direct current resistance spot welding machine was used in spot welding of 7075 aluminum alloy and the microstructure and mechanical properties of spot welding of 7075 aluminum alloy were investigated. The results show that the spot welding joint is composed of the fusion zone, the partial melted zone, and the heat affected zone. The partial melted zone is composed of columnar crystal and the fusion zone is composed of isometric crystal. The microstructure of the heat affected zone and the base metal is of rolling structures. Dendritic segregations are found in the joint. The fusion zone and heat affected zone is not as hard as the base metal. The ductile and toughness is low. The interfacial failure mode is observed in fracture macroscopic photograph of spot welding joint. The mechanical reduction is directly related to the content of alloying elements and failure mode.
作者
樊文飞
罗震
李洋
冯悦峤
赵玉津
FAN Wen f ei LUO Zhen LI Yang FENG Yueqiao CHAO Yujin(School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China Collaborative Innovation Center of Advanced Ship and Deep-Sea Exploration, Shanghai 200240, China)
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2016年第10期1601-1604,共4页
Journal of Shanghai Jiaotong University
基金
高等学校博士学科点专项科研基金项目(20130032110004)
国家自然科学基金项目(51275342
51275338)
国家自然科学青年基金项目(51405335)资助
关键词
铝合金
点焊
微观组织
力学性能
aluminum alloy
spot welding
microstructure
mechanical properties
