Effect of temperature on the tensile deformation behavior and fracture mechanism of a transient liquid-phase bonding joint of γ′-strengthened Co-based single-crystal superalloy

• Published in: Journal of materials science 2022-07, Vol.57 (25), p.12012-12033
• Main Authors: Wang, S. Y., Hou, X. Y., Cheng, Y., Sun, Y., Yang, Y. H., Li, J. G., Zhang, H. W., Zhou, Y. Z.
• Format: Article
• Language: English
• Subjects: Alloys; Base metal; Bonded joints; Bonding strength; Borides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Cobalt base alloys; Crystallography and Scattering Methods; Deformation; Deformation effects; Deformation mechanisms; Dislocation mobility; Fracture mechanics; Gamma-prime phase (crystals); Liquid phases; Materials Science; Mechanical properties; Metals & Corrosion; Microstructure; Polymer Sciences; Powder metallurgy; Researchers; Room temperature; Science; Shear strength; Shearing; Single crystals; Solid Mechanics; Solid solutions; Solidification; Superalloys; Temperature; Temperature dependence; Temperature effects; Tensile deformation; Transient liquid phase bonding
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-022-07351-0

Tensile behavior at different deformation temperature of a transient liquid-phase (TLP) bonded joint of γ′-strengthened Co-based superalloy was investigated. A temperature dependence phenomenon of the joint’s fracture position was found, which transferred from the base metal to the bonding area with increase in the temperature, and this is related to the deformation mechanism. At room temperature, dislocation shearing the γ′ phases in different areas of the joint domains the deformation and makes it heterogeneous, and more deformation has occurred at the BM because of lower content of γ′ phase, which makes the failure occurred at the BM. The deformation mechanism gradually transferred from dislocation shearing to bypassing the γ′ with increasing the temperature, making the deformation become diffused, and this can lead to the fracture of the joint’s brittle borides, and the coalescence of the boride-induced cracks makes the fracture occur at the diffusion affect zone at 600 °C~ 900 °C. As the secondary-γ′ in the joint’s isothermal solidification zone dissolves at 1000 °C, more deformation occurs there and the accumulation of micro-voids induced by the dislocation climbing leads to the fracture.