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SCIENCE CHINA Materials, Volume 63 , Issue 7 : 1279-1290(2020) https://doi.org/10.1007/s40843-020-1291-9

Tailored microstructures and strengthening mechanisms in an additively manufactured dual-phase high-entropy alloy via selective laser melting

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  • ReceivedFeb 11, 2020
  • AcceptedMar 7, 2020
  • PublishedApr 8, 2020

Abstract


Funded by

the Pre-research Fund Project of Ministry of Equipment and Development of China(61409230301)

and the Fundamental Research Funds for the Central Universities(2019kfyXMPY005,2019kfyXKJC042)


Acknowledgment

This work was supported by the Pre-research Fund Project of Ministry of Equipment and Development of China (61409230301), and the Fundamental Research Funds for the Central Universities (2019kfyXMPY005 and 2019kfyXKJC042). The authors thank the Analytical and Testing Center of HUST for SEM, EBSD, EPMA and TEM measurement.


Interest statement

The authors declare no conflict of interest.


Contributions statement

Wang Z conceived the experiments. Wang Z, Luo S and Su Y contributed to the theoretical analysis. Luo S performed the experiments and wrote the paper. All authors discussed the results and commented on the manuscript.


Author information

Shuncun Luo received his Master’s degree from Central South University in 2017. Currently, he is a PhD candidate at Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), China. His current research interest focuses on the laser additive manufacturing of advanced structural materials, such as high-entropy alloy and high-entropy light alloy.


Yue Su received her bachelor’s degree from Wuhan University of Science and Technology in 2018. Currently, she is a Master degree candidate at Wuhan National Laboratory for Optoelectronics, HUST, China. Her current research interest focuses on the laser additive manufacturing of high-entropy alloy.


Zemin Wang received his PhD degree in materials science from HUST in 2003. He did scientific research in the Multidisciplinary Research Center for Materials Processing at the University of Birmingham from 2007 to 2008. He has been a professor of materials science and optical engineering at HUST since 2011. His research interests include laser additive manufacturing, laser materials processing, materials science & engineering, and laser manufacturing engineering.


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  • Figure 1

    (a) SEM morphology of the blended AlCrCuFeNi3 powders; (b) The as-built dog-bone-shaped tensile specimens and cubic specimens of AlCrCuFeNi3 HEA.

  • Figure 2

    (a) XRD diagrams of the as-built samples at different scanning speeds; (b) partial XRD diagrams of the as-built samples at different scanning speeds. B2 denotes the ordered BCC phase.

  • Figure 3

    BSE images and EBSD phase maps with HAGBs of the as-built samples on XZ plane: (a, b) V400; (c, d) V600; (e, f) V800; (g, h) V1000.

  • Figure 4

    (a) Bright-field TEM micrograph inside the grains of the V400 sample on the XZ plane at the Z.A. of [001]; (b) HAADF-STEM micrograph of the white dotted box in (a); (c) HRTEM micrograph of the white dotted box in (b); (d) HRTEM micrograph of the yellow dotted box in (b); (e) HAADF-STEM micrograph, with the corresponding STEM-EDS images of Cr and Fe shown below.

  • Figure 5

    EPMA maps of element distribution for the V400 sample on the XZ plane.

  • Figure 6

    (a, b) High-resolution SEM images of the lamellar DP nano-structures within a grain for the as-built V400 and V1000 samples on the XZ plane; (c) high-resolution SEM image of cracks in the as-built V1000 sample on the XZ plane; (d) magnified SEM image of the red dotted box in (c).

  • Figure 7

    Schematic diagrams: (a–c) alternating nucleation and growth during the eutectic reaction; (c) FCC and B2 DP nano-structures on the XZ plane; (d) FCC and B2 DP nano-structures on the XY plane.

  • Figure 8

    Schematic illustration of grain growth mechanisms for the as-built samples: (a) V400; (b) V1000. TE represents the equilibrium solidification temperature.

  • Figure 9

    Engineering stress-strain diagram of the as-built samples at different scanning speeds.

  • Figure 10

    (a, b) Bright-field TEM images on the XY plane of the post-deformed V400 sample; (c, d) HRTEM images of the blue and red boxed zones in (b), respectively. SFs and twins are discovered; (e) IFFT image corresponding to the yellow dashed box in (b), the dislocations are marked by the red ‘T’; (f) calculated strength contributions.

  • Table 1   Table 1 Data used for the strength calculations [45,50]: Taylor factor (M), constant (α), shear modulus of matrix (G), constant (αε), shear modulus mismatch between the precipitate and matrix (∆G), anti-phase boundary energy of the precipitate (γAPB)

    Phase

    M

    α

    G (GPa)

    αε

    G (GPa)

    γAPB (J m−2)

    FCC

    3.06

    0.2

    81

    BCC

    2.73

    0.25

    83

    2.6

    3

    0.25

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