Mechanical joint performances of friction self-piercing riveted carbon fiber reinforced polymer and AZ31B Mg alloy

Carbon fiber reinforced polymer (CFRP) and AZ31B Mg alloy were joined by the friction self-piercing riveting (F-SPR) with different steel rivet shank sizes. With the increase of rivet shank size, lap shear fracture load and mechanical interlock distance increased. Ultrafine grains were formed at the joint in AZ31B as a result of dynamic recrystallization, which contributed to the higher hardness. Fatigue life of the CFRP-AZ31B joint was studied at various peak loads of 0.5, 1, 2, and 3 kN and compared with the resistance spot welded AZ31B-AZ31B from the open literature. The fatigue performance was better at higher peak load ( >2 kN) and comparable to that of resistance spot welding of AZ31B to AZ31B at lower peak loads ( <1 kN). From fractography, the crack initiation for lower peak load ( <1 kN) case was observed at the fretting positions on the top and bottom surfaces of AZ31B sheet. When peak load was increased, fretting between the rivet and the top of AZ31B became more dominant to initiate a crack during fatigue testing. (c) 2022 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer review under responsibility of Chongqing University

Automated summary

This study investigates the effects of different steel rivet shank sizes on the performance of carbon fiber reinforced polymer (CFRP) and AZ31B Mg alloy joints joined by friction self-piercing riveting (F-SPR). The results show that the lap shear fracture load and mechanical interlock distance increase with the increase of rivet shank size. Ultrafine grains are formed at the joint in AZ31B, resulting in higher hardness. In terms of fatigue life, the CFRP-AZ31B joint performs better at higher peak loads (>2 kN) and is comparable to resistance spot welding of AZ31B to AZ31B at lower peak loads (<1 kN).