Preparation of Zn-based Alloy Filler for Brazing Aluminum and Microstructure and Shear Strength of Brazed Joint

A Zn-based alloy filler was prepared by high-frequency induction heating,and its wet testing was performed by taking pure Al as matrix,and then the alloy filler was used to braze 2A12 aluminum alloy and 55%SiCp/Al composite,respectively.The microstructure,composition and melting temperature range of the alloy filler were analyzed and the shear strength of the alloy filler and brazed joints was measured.The results show that the Zn-based alloy filler was comprised of α-Al solid phase,η-Zn solid phase and eutectic structure,and its melting temperature range was 361 ℃-398 ℃.The pure Al was wetted with the molten Zn-based filler alloy.The brazed joint of the 2A12 aluminum alloy was primarily composed of η-Zn phase,thin eutectic phase,α-Al dendrites and block-like morphology α-Al phase.The brazed joint of the 55%SiCp/Al composite was primarily composed of eutectoid phase,η-Zn phase,stripe-like and thin eutectic phases.The shear strength of the filler,brazed joints of 2A12 aluminum alloy and the 55%SiCp/Al composite was 237 MPa,127 MPa and 109 MPa,respectively.