Mechanical property and microstructure of 3003 Al-alloy/Cu dissimilar metals brazed joint

3003 Al alloy/Cu dissimilar metals were brazed by using Zn-Al filler metals with different Al contents. The spreadability of filler metal on 3003 Al-alloy substrate was improved with the increase of Al content. When Al content is in the range of 10%~15%, the filler metal presented excellent spreadability.However,the spreadability gradually decreased when Al content exceeds 15% in Zn-Al filler metal.In addition, the spreadability on pure copper substrate was improved with the increase of Al content. Shear strength of brazed joint was measured. The results show brazed joint strength was improved with the increase of Al content in the filler metal. When Al content is 12%, the shear strength reached highest and a sound brazed joints could be obtained. However,when Al content exceeds 12% in Zn-Al filler metal, the strength of brazed joint was gradually decreased. The optimum composition possessing best comprehensive properties is 88Zn-12Al filler metal.