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Indexed by:期刊论文

Date of Publication:2016-03-15

Journal:MATERIALS & DESIGN

Included Journals:SCIE、EI

Volume:94

Page Number:457-466

ISSN No.:0264-1275

Key Words:Refilled friction stir spot welding; Aluminum/steel dissimilar materials; Mechanical property; ZnO

Abstract:Dissimilar materials lap joining of aluminum alloy to galvanized steel sheets was investigated with refilled friction stir spot welding (Refilled FSSW). For the lap joint between 1.0 mm thick Novelist AC 170 PX aluminum alloy and 1.2 mm thick ST06 Z galvanized steel sheets, the maximum tensile/shear fracture load is 3044 N with cross-tension fracture load of 296 N. For that between 1.5 mm thick Aleris Superlite 200 ST aluminum alloy and 1.2 mm thick ST06 Z galvanized steel sheets, the maximum tensile/shear fracture load reaches 4500 N and the maximum cross-tension fracture load is 359 N. All samples failed through the Al/steel interface during tensile/shear and cross-tension tests. The microstructure, composition, fractogragh and fracture mode of Al/steel joints were analyzed with electron probe microanalysis (EPMA), scanning electron microscope (SEM) and X-ray diffraction (XRD). Zinc and oxygen rich layer were observed in the interface on aluminum alloy side, and ZnO phase was detected on the fractured surface of both aluminumalloy and steel sides. The samples during tensile/shear test failed mainly through shear brittle fracture with features of cleavage and intergranular fracture feature. The spot weld can be distinguished as pin-refilled zone and sleeve-plunging zone due to the distribution of zinc coating. (C) 2016 Elsevier Ltd. All rights reserved.