Meng, T. L., Wang, T. F., Lin, M., Ng, Y., Tan, X. Y., Teo, S. L., Tan, C. K. I., Lim, R., & Liu, H. (2024). Grinding- and robotic hammer peening-induced modifications in the near-surface regions of laser-cladded Inconel 718 coatings. Surface and Coatings Technology, 489, 131130. https://doi.org/10.1016/j.surfcoat.2024.131130
Abstract:
Inconel 718 coatings deposited by laser-cladding (LC) on low-alloy steel substrate have been grinded followed by robotic hammer peening (RHP). White layer consisted of nanograins, smaller than 100 nm, has been observed on the surface accompanied with a deformation layer underneath after grinding and RHP. By increasing the RHP intensity (i.e., both the impact energy and the dent overlap), the residual tensile stress measured by X-ray diffraction from the surface of the coating has been monotonically reduced and eventually converted to residual compressive stress with increased in-plane anisotropy, which was accompanied with monotonically increased surface hardening up to 40.5 HRC. Grain deformations have been induced in the white- and deformation-layer, they are dominated by twinning and slipping, respectively. In terms of depth-dependent distributions of low-angle (<15°) grain boundaries and hardening, the effective cold-working thickness induced by the RHP process is over 1000 μm, which is close to the thickness of a single-pass LC deposition. Onset of porosity closures occurred upon the RHP process, especially in the near-surface regions. These findings shed light on integrity enhancement for additive manufacturing of metal alloys by LC-based techniques through introducing interpass RHP process.
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Publisher Copyright
Funding Info:
This research / project is supported by the A*STAR - RIE2020 advanced manufacturing and engineering (AME) programmatic grant through the structural metal alloys program
Grant Reference no. : A18B1b0061