Preparation of graded double-layer materials for brazing C/C composite and TC4

• Published in: Journal of alloys and compounds 2020-05, Vol.823, p.153639, Article 153639
• Main Authors: Zhang, L.X., Zhang, B., Sun, Z., Pan, X.Y., Shi, J.M., Feng, J.C.
• Format: Article
• Language: English
• Subjects: Brazed joints; Brazing; C/C composite; Copper; Foils; Graded layers; Laser; Nickel; Room temperature; Shear strength; Substrates; Thermal expansion; Titanium base alloys
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.153639

In this paper, graded double-layer materials were prepared on TC4 alloy. For the first layer, WC particles were injected into the surface of the TC4 in order to mitigate the CTE of the TC4 substrate. For the second layer, Cu-Ni-WC powder was cladded on the first layer for improving the plasticity. Thermal expansion coefficients, microstructures, and sectional hardness distribution of the graded layers were characterized and analyzed. The laser treated TC4 was then successfully brazed with the C/C using a Ti foil. Microstructure of the brazed joint was investigated in detail. For comparison, C/C composites and the TC4 alloy were also brazed directly. Results show that Room-temperature shear strength of the brazed joint was improved by 89% when the graded double-layer materials were applied, comparing with the directly brazed joint. [Display omitted] •Graded double-layer materials were prepared on TC4 surface using a laser cladding approach.•CTE of Layer I adjacent to TC4 containing low-expansion WC particles is much closer to that of the C/C composite.•Layer II with Cu–Ni solid solution possesses desirable ductility.•Shear strength of the C/C-TC4 brazed joints increased by 89% after the preparation of the graded double-layer materials.