Compositionally graded AlxCoCrFeNi high-entropy alloy manufactured by laser powder bed fusion

Compositionally graded AlxCoCrFeNi high-entropy alloy manufactured by laser powder bed fusion

Materialia

10.1016/j.mtla.2021.101308

http://dx.doi.org/10.1016/j.mtla.2021.101308

Fengxia Wei, Siyuan Wei, Kwang Boon Lau, Wei Hock Teh, Jing Jun Lee, Hwee Leng Seng, Cheng Cheh Tan, Pei Wang, Upadrasta Ramamurty

General Materials Science

24 December 2021

Wei, F., Wei, S., Lau, K. B., Teh, W. H., Lee, J. J., Seng, H. L., Tan, C. C., Wang, P., & Ramamurty, U. (2022). Compositionally graded AlxCoCrFeNi high-entropy alloy manufactured by laser powder bed fusion. Materialia, 21, 101308. https://doi.org/10.1016/j.mtla.2021.101308

A high entropy alloy AlxCrCoFeNi (x = 0.07–0.88) coupon with a stepwise compositional gradation was fabricated by laser powder bed fusion (L-PBF) via in situ alloying of the blended metal powders. The chemical compositions, microstructures and mechanical properties of different regions of the coupon were examined to investigate the effect of Al content on the formation of different constituent phases. The maximum Al that can enable crack free printing was observed to be x = 0.5. Microstructural characterization indicates that grain morphologies, textures and phase variations in the graded alloys are closely related to x. Three phases were found across the graded coupon, i.e., face centered cubic (FCC), body centered cubic (BCC) solid solutions, and intermetallic B2. The phase variations can be attributed to the Al-induced lattice distortion and valence electron concentration. Further analysis suggests that the range of duplex FCC+BCC phases region is insensitive to cooling rates and could be mediated by formation of B2 phase. Nanoindentation studies show a steep increase in hardness along with the occurrence of BCC phase.

Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

This research / project is supported by the Agency for Science, Technology and Research - Structural Metals Alloys Programme
Grant Reference no. : A18b1B0061

https://oar.a-star.edu.sg/communities-collections/articles/18330

2589-1529

Institute of Materials Research and Engineering