What is it about?

Both strength and ductility are crucial properties for metallic materials. However, a paradox between strength and ductility constantly obsessing researchers, which calls the trade-off. High-entropy alloys (HEAs), or multi-principal element alloys (MPEAs), has becoming a scientific hot button in recent years. Most of HEAs are homogeneous structure with rather low yield strength. Hetero-structure (HS) is an effective method to alleviate the trade-off between strength and ductility by some deliberate process for homogeneous materials.

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Why is it important?

Our work introduce hetero-structure in Fe50Mn30Co10Cr10 HEA. As a result, the yield strength increase by 500 MPa without decrease of ductility, compared with traditional homogeneous structure samples. The strain gradient is observed during the deformation of HS samples because of the difference of strength in the heterogeneous microstructure. Thus, a large number of geometrically necessary dislocations (GNDs) pile up in the hetero-boundary so that hetero-deformation-induced(HDI) stress and HDI hardening are caused.

Perspectives

This work have made some analysis for the HDI stress results from different kinds of grain size or phase of microstructure by EBSD. It is helpful to made quantitative analysis by experimental approach, such as synchrotron radiation, or simulation approach.

Dong Liu
University of the Chinese Academy of Sciences

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This page is a summary of: Hetero-deformation-induced (HDI) plasticity induces simultaneous increase in both yield strength and ductility in a Fe50Mn30Co10Cr10 high-entropy alloy, Applied Physics Letters, September 2021, American Institute of Physics,
DOI: 10.1063/5.0065148.
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