Deformation mechanisms of Mo alloyed FeCoCrNi high entropy alloy: In situ neutron diffraction

Biao Cai; Bin Liu; Saurabh Kabra; Yiqiang Wang; Kun Yan; Peter D. Lee; Yong Liu

doi:10.1016/j.actamat.2017.01.034

Deformation mechanisms of Mo alloyed FeCoCrNi high entropy alloy: In situ neutron diffraction

Biao Cai
, Bin Liu
, Saurabh Kabra
, Yiqiang Wang
, Kun Yan
, Peter D. Lee
, Yong Liu

Research output: Contribution to journal › Article › peer-review

201 Scopus citations

Abstract

A FeCoCrNiMo_0.23 high entropy alloy was processed by powder metallurgy with two conditions: hot extruded and annealed. In situ neutron diffraction, together with electron microscopy, was used to study the deformation mechanisms and concomitant microstructural evolution for both conditions. The as-extruded alloy has a single face-centered-cubic structure with a calculated stacking fault energy of ∼19 mJ/m². When the alloy is tensile deformed, nano-twins and microbands are induced, resulting in an excellent combination of strength and ductility (784 MPa ultimate tensile strength and over 50% elongation). Annealing at 800 °C for 72 h increases the strength of the alloy but decreases its ductility. This is due to the decomposition of the alloy after annealing, causing the formation of Mo-rich intermetallic particles and a decrease of the stacking fault probability. These results highlight that combined mechanisms (i.e. solute strengthening and twin/microband induced plasticity) can effectively improve both the strength and ductility of high entropy alloys.

Original language	English
Pages (from-to)	471-480
Number of pages	10
Journal	Acta Materialia
Volume	127
DOIs	https://doi.org/10.1016/j.actamat.2017.01.034
State	Published - Apr 1 2017
Externally published	Yes

Funding

The authors thanks ISIS (the Rutherford Appleton Laboratory, UK) for providing the beamtime (RB1610297) and staff at EnginX beamline for support. B.C., Y.Q.W. and P.D.L. acknowledge the support provided by the Research Complex at Harwell, and funding from the UK-EPSRC (EP/K007734/1, EP/I02249X/1 and EP/L018705/1). Y.L. and B.L. acknowledge the National Natural Science Foundation of China (51671217), and the Projects of Innovation-driven Plan in Central South University of China (2015CX004). The authors are grateful to Drs. Cunnea and Gilchrist at Research Complex at Harwell for assistance with the TEM analysis.

Keywords

High entropy alloy
Lattice strains
Neutron diffraction
Stacking faults
Twin induced plasticity

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10.1016/j.actamat.2017.01.034

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title = "Deformation mechanisms of Mo alloyed FeCoCrNi high entropy alloy: In situ neutron diffraction",

abstract = "A FeCoCrNiMo0.23 high entropy alloy was processed by powder metallurgy with two conditions: hot extruded and annealed. In situ neutron diffraction, together with electron microscopy, was used to study the deformation mechanisms and concomitant microstructural evolution for both conditions. The as-extruded alloy has a single face-centered-cubic structure with a calculated stacking fault energy of ∼19 mJ/m2. When the alloy is tensile deformed, nano-twins and microbands are induced, resulting in an excellent combination of strength and ductility (784 MPa ultimate tensile strength and over 50\% elongation). Annealing at 800 °C for 72 h increases the strength of the alloy but decreases its ductility. This is due to the decomposition of the alloy after annealing, causing the formation of Mo-rich intermetallic particles and a decrease of the stacking fault probability. These results highlight that combined mechanisms (i.e. solute strengthening and twin/microband induced plasticity) can effectively improve both the strength and ductility of high entropy alloys.",

keywords = "High entropy alloy, Lattice strains, Neutron diffraction, Stacking faults, Twin induced plasticity",

author = "Biao Cai and Bin Liu and Saurabh Kabra and Yiqiang Wang and Kun Yan and Lee, \{Peter D.\} and Yong Liu",

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doi = "10.1016/j.actamat.2017.01.034",

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T1 - Deformation mechanisms of Mo alloyed FeCoCrNi high entropy alloy

T2 - In situ neutron diffraction

AU - Cai, Biao

AU - Liu, Bin

AU - Kabra, Saurabh

AU - Wang, Yiqiang

AU - Yan, Kun

AU - Lee, Peter D.

AU - Liu, Yong

PY - 2017/4/1

Y1 - 2017/4/1

N2 - A FeCoCrNiMo0.23 high entropy alloy was processed by powder metallurgy with two conditions: hot extruded and annealed. In situ neutron diffraction, together with electron microscopy, was used to study the deformation mechanisms and concomitant microstructural evolution for both conditions. The as-extruded alloy has a single face-centered-cubic structure with a calculated stacking fault energy of ∼19 mJ/m2. When the alloy is tensile deformed, nano-twins and microbands are induced, resulting in an excellent combination of strength and ductility (784 MPa ultimate tensile strength and over 50% elongation). Annealing at 800 °C for 72 h increases the strength of the alloy but decreases its ductility. This is due to the decomposition of the alloy after annealing, causing the formation of Mo-rich intermetallic particles and a decrease of the stacking fault probability. These results highlight that combined mechanisms (i.e. solute strengthening and twin/microband induced plasticity) can effectively improve both the strength and ductility of high entropy alloys.

AB - A FeCoCrNiMo0.23 high entropy alloy was processed by powder metallurgy with two conditions: hot extruded and annealed. In situ neutron diffraction, together with electron microscopy, was used to study the deformation mechanisms and concomitant microstructural evolution for both conditions. The as-extruded alloy has a single face-centered-cubic structure with a calculated stacking fault energy of ∼19 mJ/m2. When the alloy is tensile deformed, nano-twins and microbands are induced, resulting in an excellent combination of strength and ductility (784 MPa ultimate tensile strength and over 50% elongation). Annealing at 800 °C for 72 h increases the strength of the alloy but decreases its ductility. This is due to the decomposition of the alloy after annealing, causing the formation of Mo-rich intermetallic particles and a decrease of the stacking fault probability. These results highlight that combined mechanisms (i.e. solute strengthening and twin/microband induced plasticity) can effectively improve both the strength and ductility of high entropy alloys.

KW - High entropy alloy

KW - Lattice strains

KW - Neutron diffraction

KW - Stacking faults

KW - Twin induced plasticity

UR - https://www.scopus.com/pages/publications/85012250776

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DO - 10.1016/j.actamat.2017.01.034

M3 - Article

AN - SCOPUS:85012250776

SN - 1359-6454

VL - 127

SP - 471

EP - 480

JO - Acta Materialia

JF - Acta Materialia

ER -

Deformation mechanisms of Mo alloyed FeCoCrNi high entropy alloy: In situ neutron diffraction

Abstract

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Keywords

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