Effect of Fe-Al intermetallic compound on mechanical property of aluminum/steel brazed joint

3003 Al-alloy/Q235 steel dissimilar metals were brazed by Zn-Al filler metals with different Al contents. The spreading experiment results indicate that the spreadability improves with the increase of Al content in the filler metal on 3003 Al-alloy substrate and Q235 steel substrate. When Al content is 15%, the filler metal presents the best spreadability on 3003 Al-alloy substrate and Q235 steel substrate．However，the spreadability gradually deteriorates when Al content exceeds 15% in Zn-Al filler metal. In addition, the shear strength of the brazed joint was measured. The results show the joint strength improves with the increase of Al content in the filler metal. When Al content is 12%, the shear strength of the brazed joint gets highest. However，when Al content exceeds 12% in Zn-Al filler metal, the joint strength gradually decreases. The optimum content possessing best comprehensive properties is 88Zn-12Al filler metal.