Effect of In and Pr on the Microstructure and Properties of Low-Silver Filler Metal

• Main Authors: Jie Wu, Songbai Xue, Peng Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Crystals
• Subjects: low-silver filler metals; melting temperature; wettability; microstructure; mechanical properties
• Online Access: https://www.mdpi.com/2073-4352/11/8/929

The novel low-silver 12AgCuZnSn filler metals containing In and Pr were used for flame brazing of copper and 304 stainless steel in this study. The effects of In and Pr content on the melting temperature, wettability, mechanical properties and microstructure of 12AgCuZnSn filler metal were analyzed. The results indicate that the solidus and liquidus temperatures of filler metals decrease with the addition of In. Trace amounts of Pr have little impact on the melting temperature of the low-silver filler metals. In addition, the spreading area of filler metals on copper and 304 stainless steel is improved. The highest shear strength of brazed joint is 427 MPa when the content of In and Pr are 2 wt.% and 0.15 wt.%, respectively. Moreover, it is observed that the trace amount of Pr significantly refines the microstructure of brazed joint matrix. A bright Pr₃Cu₄Sn₄ phase is found in filler metal and brazing seam when the contents of In and Pr are 5 wt.% and 0.5 wt.%, respectively.