Evolution of Interfacial Microstructure during Resistance Spot Welding of Cu and Al with Ni-P Coating

Dissimilar materials of copper (Cu) to aluminum (Al) with nickel-phosphorus (Ni-P) coatings were joined using resistance spot welding. The Ni-P coatings were electroless plated on the Al surfaces to eliminate the formation of brittle Cu-Al intermetallic compounds (IMCs) at the faying interface of Cu to Al. Three welding schedules with various heat input were used to produce different interfacial microstructure. The evolution of interfaces in terms of phase constitution, elemental distribution, and defects (gaps and voids) was characterized and the formation mechanisms were elucidated. During the welding, the bonding between Cu and Ni-P form through solid-state diffusion, while the faster diffusion rate of Cu relative to Ni and P atoms promotes the generation of sub-micro voids. As the heat input increases, gaps at the Cu/Ni-P interface diminish accompanied by increase of sub-micro voids. A moderate schedule helps to remove the gaps and inhibit the voids formation. An Al3Ni layer and nanovoids were found around the interface of Ni-P/Al. The increased heat input decreases the grain size of Al3Ni at the interface by eutectic remelting and increases the nanovoids by enhanced nanoscale Kirkendall effect.

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Work Title Evolution of Interfacial Microstructure during Resistance Spot Welding of Cu and Al with Ni-P Coating
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Open Access
Creators
  1. Nannan Chen
  2. Hongliang Wang
  3. Jingjing Li
  4. Vic Liu
  5. James Schroth
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. Journal of Manufacturing Science and Engineering, Transactions of the ASME
Publication Date April 1, 2022
Publisher Identifier (DOI)
  1. https://doi.org/10.1115/1.4052387
Deposited November 16, 2021

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  • Created
  • Added manu_144_4_041001.pdf
  • Added Creator Nannan Chen
  • Added Creator Hongliang Wang
  • Added Creator Jingjing Li
  • Added Creator Vic Liu
  • Added Creator James Schroth
  • Published
  • Updated
  • Updated