Effect of ZrO2 Nanomaterials on Wettability and Interfacial Characteristics of Al-19Cu-11Si-2Sn Filler Metal for Low Temperature Al to Cu Dissimilar Brazing

Abstract

Dissimilar Al 3003 and Cu tubular components were successfully brazed without interface cracking using ZrO2 nanomaterials reinforced with Al-19Cu-11Si-2Sn filler. The filler was initially cast using an induction furnace and processed into ring form for brazing. Al-19Cu-11Si-2Sn filler with coarse CuAl2 and Si phases (43 and 20 μm) were refined to 8 and 4 μm, respectively, after the addition of 0.1 wt. % ZrO2 and shows significant improvement in the mechanical properties. ZrO2 nanomaterials’ induced diffusion controlled growth mechanism is found be the responsible for the refinement of CuAl2 intermetallic and Si particles. The wettability of Al-19Cu-11Si-2Sn-0.1ZrO2 increased to 78.17% on Cu side and 93.19% on the Al side compared from 74.8% and 89.9%, respectively. Increase in the yield strength, ultimate tensile strength, and percentage elongation were noted for the brazed joints. Microstructure of induction brazed joint with 40 kW for 6 seconds using Al-19Cu-11Si-2Sn-0.1ZrO2 filler shows thin interfacial CuAl2 intermetallic compound along the copper side and inter-diffusion region along the aluminum side and their respective mechanism is discussed. The tensile strength of the joints increased with increasing the nanomaterials addition and shows a base metal fracture. Analysis of fractured samples shows the effectiveness of ZrO2 reinforced filler in crack propagation through the filler.