Interfacial microstructure and mechanical properties of dissimilar aluminum/steel joint fabricated via refilled friction stir spot welding. (January 2020)

• Record Type: Journal Article
• Authors: Li, Peng; Chen, Su; Dong, Honggang; Ji, Hua; Li, Yongbing; Guo, Xin; Yang, Guoshun; Zhang, Xiaosheng; Han, Xinliang
• Is Part Of: Journal of manufacturing processes. Volume 49(2020)
• Page Start: 385
• Page End: 396
• Publication Date: 2020-01
• Subjects: Aluminum alloy -- Uncoated low carbon steel -- Refilled friction stir spot welding -- Mechanical property -- Microstructure; Production management -- Data processing -- Periodicals; Manufacturing processes -- Periodicals; Procestechnologie; Productietechniek; Production -- Gestion -- Informatique -- Périodiques; Fabrication -- Périodiques; Manufacturing processes; Production management -- Data processing; Periodicals; 670.5
• DOI: 10.1016/j.jmapro.2019.09.047
• Languages: English
• ISSNs: 1526-6125

Abstract

Highlights: Aluminum alloy was refilled friction stir spot welded to uncoated low carbon steel. The maximum tensile/shear fracture load of joint reached 3745 N. Sleeve plunging into steel could greatly improve mechanical property of joint. Metallurgical and mechanical bonding resulted in the highest fracture load. Abstract: Aluminum alloy and steel hybrid structures offer clear advantages in weight reduction and energy conservation for the automotive industry. This paper exhibits sound refilled friction stir spot welded joints between the aluminum alloy and ST16 steel sheets with the maximum tensile/shear and cross-tension fracture loads of 3745 N and 1073 N, respectively. All samples failed through the interface of aluminum alloy/steel joints during tensile/shear test and cross-tension test. The microstructure and fracture mode of the joints were studied with the scanning electron microscope, electro-probe microanalyzer and X-ray diffraction. For the joints where the sleeve had not plunged into the ST16 steel, the effect of the sleeve plunging depth and rotation speed on the tensile/shear fracture load cannot be identified, as an intermetallic compounds layer formed between Al and Fe, which was almost uniform across the interface. The mechanical performance of joints increased dramatically when the sleeve plunged into the ST16 steel because of metallurgical bonding and mechanical interlocking in the sleeve-affected zone. However, this process caused considerable wear to the tool and shortened its service life. The bonding mechanism was investigated by studying joints between the aluminum alloy and galvanized steel for the same welding parameters.