Brazing Metallurgical Bonding Method Of Bimetallic Terminals: Micro-interface Analysis And Process Control

Under the high reliability requirements of new energy and power transmission components, the core of bimetallic lugs price list's manufacturing lies in the metallurgical bonding of dissimilar metal interfaces. Brazing is not simply solder filling; it involves atomic diffusion and chemical reactions between liquid solder and solid base material to form a bonding layer with a specific phase composition. This process determines the terminal's conductivity stability and fatigue life.

Phase Evolution of the Interface Diffusion Layer

Due to the welding characteristics of copper and aluminum dissimilar metals, bimetallic terminals form a distinct transition zone during brazing. With the addition of a silver interlayer, a "tooth-like" ternary eutectic phase forms at the copper side boundary, while the molten zone is dominated by dendritic α-Al. The homogeneity of this microstructure directly reflects the metallurgical bonding quality of cable lug bimetal. The difference in diffusion rates of different elements at the interface leads to a regular phase gradient change in the reaction layer from the weld center towards the base material.

Refined Control of Process Parameters

In the fusion brazing process under vacuum or a protective atmosphere, a diffusion layer approximately 30 micrometers wide can be formed at the joint interface of the bimetallic terminal. To optimize this structure, a multi-layered "sandwich" solder design was employed in the engineering. For example, by adding a pure Cu buffer layer between the Cu-TiH₂ layer and the Ag-Cu alloy layer, the plastic deformation capacity of the intermediate layer can release residual welding stress, effectively suppressing the excessive growth of brittle intermetallic compounds.

What characterization methods do you primarily use for observing the interface microstructure of terminals in actual production? Feel free to leave a comment and discuss.