Effects of rare-earth element Pr on properties of Ag30CuZnSn filler metal

This paper investigated the melting temperature, spreadability and microstructure of Ag30CuZnSn filler metal, the mechanical properties of welded seams brazed with Ag30CuZnSn filler metal with different contents of rare-earth element Pr. The results show that the spreadability of silver-base filler metal was improved with the addition of Pr. When the Pr content was more than 0.15wt.%, the spreadability of silverbase filler metal was deteriorated greatly. The mechanical properties of welded seam were also examined and analyzed, and the results indicate that the tensile strength gradually increased with the increase of Pr content. When the Pr content was 0.15%, the tensile strength reached the maximum. It was also found that the addition of Pr can refine the grain size of the filler metal. When the Pr content was 0.15wt.%, the microstructure of silver-base filler metal was the best, and it verifies that the optimum addition content of Pr is 0.15wt.% as well.