Effect of the addition of Sb and rare-earth elements La and Nd on the properties of Cu/6061Al with Zn–10Al–5Cu filler metals

The wetting ability, mechanical properties and microstructure distribution of a new solder based on a Zn–10Al–5Cu alloy with different amounts of Sb and rare earths added were studied. The results indicate that the spreading area of solder alloy decreases first and then increases and the shear strength of the Copper–aluminum joint increases with the increase of Sb element. The microstructure of the brazed weld matrix was refined. The Zn–10Al–5Cu–1.5Sb solder obtained by the test had better properties. Then, the rare earth (La and Nd) was added in Zn–10Al–5Cu–1.5Sb filler metal. It makes the wettability further improved. The wetting property of solder was the best with the 0.15 wt% RE addition. The large black eutectoid microstructure in the matrix become smaller and the number of IMC near the copper side increases with the addition of rare earth elements. The shear strength of brazed seam reaches the maximum when the content of rare earth element is 0.15%. Therefore, the optimum addition amount of the rare earth in Zn–10Al–5Cu–1.5Sb is about 0.15%.