Comparative study on mechanical properties of aluminum alloy and BFRP single lap joints with hygrothermal aging

Abstract

ABSTRACT The hygrothermal aging environment of 80°C/95%RH was selected to conduct the aging tests on single lap joints of aluminum alloy-basalt fiber reinforced polymer composite(Al-BFRP),Al-Al, and BFRP-BFRP. The effects on the failure strength, failure displacement and failure modes of the joints were analyzed. Fourier transform infrared spectroscopy (FTIR) was used to test the changes of chemical groups of adhesive and BFRP. The microstructure of the failure section was observed by scanning electron microscope (SEM). The results show that the failure displacement of the Al-Al joints is lower than that of the Al-BFRP and BFRP-BFRP joints. The failure strength of Al-BFRP joints is lower than that of Al-Al joints and higher than that of BFRP-BFRP joints, while the decline rate of failure strength of Al-BFRP joints during aging is the highest. The mechanical properties of the adhesive were weakened and the fiber tear proportion on the bonding surface decreased. The failure mode of unaged Al-Al joint is adhesive cohesion. The failure mode of aged Al-Al joint appears the interface failure spreading from the edge to the center, leading to the decrease of the failure strength.