Effect of titanium on microstructure and properties of Zn-22Al filler metals

The effects of the titanium on the resistivity, melting temperature, spreadability, microstructure, and shear strength of Zn-22Al filler metal were studied.The results indicated that with the addition of Ti, the resistivity and the melting temperature rose slightly, and the spreadability was significantly improved especially when the content of Ti was 0.03%.However, the addition of excessive amount of Ti would deteriorate the spreadability of Zn-22Al filler metal.It has been found that Ti could refine the microstructure of the filler metal, and the size of η-Zn phase decreases remarkably.When the content of Ti exceeds 0.15%, the η-Zn phase tends to become coarse, and the shear strength of Cu/Al joint reaches the peak value 84.64 MPa when brazed with Zn-22Al-0.03Ti filler metal.