Brazing of Gr/2024Al composite and TC4 using AgCuTi filler with the assist of Ti-Al-C-Cu interlayer

Abstract

Abstract In order to braze Gr/2024Al composite at low temperature to keep its heat insulation property, a novel thermal explosion assisting brazing method was designed. Through this method, the thermal explosion reaction of Ti-Al-C-Cu interlayer offered additional heat, and AgCuTi filler reacted with Gr/2024Al composite under the melting point of AgCuTi. Based on the theoretical calculation and DSC analysis, the composition of Ti-Al-C-Cu interlayer was designed. The microstructure and mechanical properties of brazed joint was investigated, and the brazing parameters were optimized. The results showed that AgCuTi reacted with the Gr/2024Al composite to form Ti3AlC2 layer, and a continuous TiAl3 layer acted as the reaction layer near the TC4 alloy. The high preheating temperature and long holding time would promote the reaction of AgCuTi filler, Gr/2024Al and Ti-Al-C-Cu interlayer, and Al5CuTi2 phase volume in the brazing zone increased. The Al5CuTi2 distribution affected the joint strength significantly. The optimized joint strength reached 11\u2009MPa when the joint was brazed at 650\u2009°C for 15\u2009min.