| Autor: |
Nannan Chen, Hongliang Wang, Pawan Veeresh, Jingjing Li, Jay Oswald, Liang Xi, Sean Wagner, Ryan Sekol, Vic Liu, Ke Wang, Thomas Perry, James Schroth |
| Jazyk: |
angličtina |
| Rok vydání: |
2021 |
| Předmět: |
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| Zdroj: |
Materials & Design, Vol 199, Iss , Pp 109435- (2021) |
| Druh dokumentu: |
article |
| 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: |
Directory of Open Access Journals |
| Externí odkaz: |
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