Achieving brittle-intermetallic-free and high-conductivity aluminum/copper joints using nickel-phosphorus coatings
| Autor: | Wagner Sean R, Jay Oswald, James G. Schroth, Ryan C. Sekol, Jingjing Li, Hongliang Wang, Thomas A. Perry, Pawan Veeresh, Vic Liu, Liang Xi, Ke Wang, Nannan Chen |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Dissimilar metal joining Intermetallic chemistry.chemical_element Numerical simulation 02 engineering and technology Welding engineering.material 010402 general chemistry 01 natural sciences law.invention Brittleness Coating law lcsh:TA401-492 General Materials Science Ni-P coating Composite material Eutectic system Mechanical Engineering Interface 021001 nanoscience & nanotechnology Microstructure Copper 0104 chemical sciences chemistry Mechanics of Materials Heat generation engineering lcsh:Materials of engineering and construction. Mechanics of materials 0210 nano-technology Transmission electron microscopy |
| Zdroj: | Materials & Design, Vol 199, Iss, Pp 109435-(2021) |
| ISSN: | 0264-1275 |
| DOI: | 10.1016/j.matdes.2020.109435 |
| Popis: | Mechanical degradation due to brittle intermetallic compounds (IMCs) formed at the faying interface is a predominant deficiency in dissimilar metal joints. In copper/aluminum (Cu/Al) joints, additional defects (such as partially-bonded interfaces, porosity and cracks) lead to further weakened strength and lowered electrical conductivity. In this study, nickel‑phosphorus (Ni-P) coatings are deposited on Al to address these issues. With the aid of Ni-P coatings, the detrimental Cu-Al IMC is eliminated, a donut-shaped weld with a partially-bonded interface is evolved into an hourglass-shaped weld with a fully-bonded interface, while the porosity and cracks are inhibited. Numerical simulations indicate that, during the welding without Ni-P coating, the Al oxide aggravates the inhomogeneity of heat generation at the Cu/Al interface, promoting the formation of donut-shaped weld and defects. Microstructural characterization suggests that the Ni-P coatings obstruct the Cu-Al interdiffusion which results in CuAl2-free interfaces, while the amorphous Ni-P convert into eutectic microstructure composed of nanocrystalline Ni and fine Ni3P grains through a solid-state transformation. Using the Ni-P coatings, joints gain an improvement of 140% in lap-shear peak load and a 25-fold increase in lap-shear maximum elongation, as well as an 84% reduction in electrical resistance. |
| Databáze: | OpenAIRE |
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