Improving weld formability by a novel dual-rotation bobbin tool friction stir welding

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2018,（1）
• 页码范围: 135-139
• 页数: 5页
• 语种: 英文

摘要

A novel dual-rotation bobbin tool friction stir welding (DBT-FSW) was developed,in which the upper shoulder (US) and lower shoulder (LS) have different rotational speeds.This process was tried to weld 3.2 mm thick aluminum-lithium alloy sheets.The metallographic analysis and torque measurement were carried out to characterize the weld formability.Experimental results show that compared to conventional bobbin tool friction stir welding,the DBT-FSW has an excellent process stability,and can produce the defect-free joints in a wider range of welding parameters.These can be attributed to the significant improvement of material flow caused by the formation of a staggered layer structure and the unbalanced force between the US and LS during the DBT-FSW process.