Effect of high temperature exposure on adhesively bonded basalt fiber reinforced polymer composite-aluminum alloy single lap joints

To investigate the degradation mechanism of new material adhesive structures applied to automobile after experiencing continuous high temperature environment, adhesively bonded aluminum alloy-aluminum alloy(Al-Al) and basalt fiber reinforced polymer composite-aluminum alloy(BFRP-Al) single lap joints were manufactured and then were exposed at 80℃ for 0 day, 5 days, 10 days, 15 days. DSC and FTIR were used to analyze the glass transition temperature (T_g) and chemical components changes of the adhesive and BFRP composite after high temperature exposure. The quasi-static state tensile tests were conducted to acquire the failure loads and the failure modes were also analyzed. The results show that the adhesive involves post-curing and oxidation reactions and the BFRP composite involves thermal decomposition and oxidation reactions under the continuous high temperature environment. The failure load of the Al-Al joints constantly increases and the failure mode is cohesive failure before and after aging which is determined by the adhesive. While the failure load of the BFRP-Al joints firstly increases and then decreases and the failure mode is mixed failure of cohesive and fiber tear with different aging time which is affected by the adhesive and BFRP composite together. With the increase of aging time, the area of the BFRP composite tear gets larger and the failure mode tends to be the basalt fiber/resin interface failure which shows that the effect of the degradation of BFRP composite is more and more significant.