TY - JOUR
T1 - A study on the microstructure and mechanical behavior of CoCrFeNi high entropy alloy fabricated via laser powder bed fusion: Experiment and crystal plasticity finite element modelling
AU - Zhang, Yongyun
AU - Yang, Congrui
AU - Ke, Haibo
AU - Chan, K. C.
AU - Wang, Weihua
N1 - Funding information:
The work described in this paper was mainly supported by the funding support to the State Key Laboratories in Hong Kong from the Innovation and Technology Commission (ITC) of the Government of the Hong Kong Special Administrative Region (HKSAR), China. The authors would also like to express their sincere thanks to the financial support from the Research Office (Project code: BBXD and BBX2) of The Hong Kong Polytechnic University, Guangdong Major Project of Basic and Applied Basic Research, China (Grant No. 2019B030302010), the National Key Research and Development Program of China (Grant No.
2021YFA0716302), the National Natural Science Foundation of China (Grant No. 52071222), Guangdong Basic and Applied Basic Research, China (Grant No. 2020B1515130007).
Publisher Copyright:
© 2024 Elsevier B.V.
PY - 2024/2
Y1 - 2024/2
N2 - Additive manufacturing facilitates the design of high entropy alloys (HEAs) with well-performing properties compared to conventional manufacturing methods. However, a significant obstacle to the industrial application of the equimolar CoCrFeNi HEA fabricated through additive manufacturing is the detrimental impact of thermal cracks on its performance. Here, thermal crack-free CoCrFeNi HEAs with enhanced mechanical properties were obtained by optimizing the energy input in laser powder bed fusion (LPBF). The lower energy input resulted in finer grains, leading to simultaneously improved strength and ductility compared to the one fabricated via higher energy input. To understand the relationship between the microstructure and mechanical properties, crystal plasticity element modelling (CPFEM) was employed to accurately model the experimental results. Using the collected constitutive parameters for CoCrFeNi HEA after CPFEM, in-situ tensile modelling was implemented on a converted orientation map of an as-LPBF CoCrFeNi sample. The CPFEM results reveal that the appearance of deformed twins during the initial plastic deformation stage is attributed to a complex distribution of shear strain on the grain boundaries. The interaction between the deformed twins and dislocation motion emerged as the primary deformation mechanisms in the as-LPBF CoCrFeNi HEA, resulting in complex stress and strain distributions. By combining experimental data with modelling techniques, a viable approach to comprehending the detailed deformation mechanism of deformed twins was established.
AB - Additive manufacturing facilitates the design of high entropy alloys (HEAs) with well-performing properties compared to conventional manufacturing methods. However, a significant obstacle to the industrial application of the equimolar CoCrFeNi HEA fabricated through additive manufacturing is the detrimental impact of thermal cracks on its performance. Here, thermal crack-free CoCrFeNi HEAs with enhanced mechanical properties were obtained by optimizing the energy input in laser powder bed fusion (LPBF). The lower energy input resulted in finer grains, leading to simultaneously improved strength and ductility compared to the one fabricated via higher energy input. To understand the relationship between the microstructure and mechanical properties, crystal plasticity element modelling (CPFEM) was employed to accurately model the experimental results. Using the collected constitutive parameters for CoCrFeNi HEA after CPFEM, in-situ tensile modelling was implemented on a converted orientation map of an as-LPBF CoCrFeNi sample. The CPFEM results reveal that the appearance of deformed twins during the initial plastic deformation stage is attributed to a complex distribution of shear strain on the grain boundaries. The interaction between the deformed twins and dislocation motion emerged as the primary deformation mechanisms in the as-LPBF CoCrFeNi HEA, resulting in complex stress and strain distributions. By combining experimental data with modelling techniques, a viable approach to comprehending the detailed deformation mechanism of deformed twins was established.
KW - Crystal plasticity element modelling
KW - Deformation mechanism
KW - Equimolar CoCrFeNi high entropy alloy
KW - Laser powder bed fusion
KW - Mechanical properties
KW - Microstructure
UR - http://www.scopus.com/inward/record.url?scp=85182890223&partnerID=8YFLogxK
U2 - 10.1016/j.msea.2024.146111
DO - 10.1016/j.msea.2024.146111
M3 - Journal article
AN - SCOPUS:85182890223
SN - 0921-5093
VL - 893
JO - Materials Science and Engineering: A
JF - Materials Science and Engineering: A
M1 - 146111
ER -