Advances in induction brazing of copper and dissimilar metals: Challenges and emerging trends

Induction brazing is emerging as a promising technique in current manufacturing processes, particularly noted for its effectiveness in the precise control of heat input, localized heating and rapid processing time. This joining technique is advantageous in industries such as heat pump and refrigeration manufacturing, which require precise and effective joining techniques, particularly for brazing copper and dissimilar metal pipes. Additionally, this technique is environmentally friendly, energy-efficient, cost-effective, and well-suited for automation.

However, studies have shown that induction brazing of copper and dissimilar metals presents several significant challenges, including thermal distortion-induced cracks due to unoptimized heat input and porosity defects stemming from inadequate filler metal penetration and suboptimal gap size between the joint, these issues can compromise joint integrity, as well as system durability and sustainability. Furthermore, the incompatible thermophysical properties of dissimilar materials and interconnectors pose substantial difficulties in achieving complete metallurgical bonding. The formation of undesirable microstructures, such as hard and brittle intermetallic compounds (IMCs), can further affect the structural, mechanical, and thermal properties of brazed joints.

This review systematically examines the effects of the most significant induction brazing process parameters on joint performance. Specifically, the effects of heat input, geometrical gap size between the joints, and composition of the filler material on the quality of brazed joints are discussed. Moreover, this review explores the induction brazing of copper with dissimilar metals, including copper with aluminum and copper with stainless steel. The impact of key process parameters on the joint quality of these materials was analyzed. Additionally, opportunities, challenges, and strategies to mitigate the challenges in induction brazing of copper and dissimilar metals are presented induction brazing are presented along with future research directions.