Si-induced stacking fault energy modulation and its impact on deformation mechanisms in non-equimolar CoCrCuNi alloys

Pin-Hua Chen; Ting-En Shen; Hsin-Chieh Jhou; Wei-Chen Hsu; Chong-Chi Chi; Ming-Yen Lu; Jien-Wei Yeh; Che-Wei Tsai

doi:10.1016/j.matchar.2025.115557

Si-induced stacking fault energy modulation and its impact on deformation mechanisms in non-equimolar CoCrCuNi alloys

Pin-Hua Chen, Ting-En Shen, Hsin-Chieh Jhou, Wei-Chen Hsu, Chong-Chi Chi, Ming-Yen Lu, Jien-Wei Yeh Che-Wei Tsai

Materials characterization, Vol.229, 115557

11/2025

: https://doi.org/10.1016/j.matchar.2025.115557

: WOS:001583211300001

Deformation twinning

High-entropy alloy

Phase transformation

Stacking fault energy

X-ray diffraction is utilized to estimate the stacking fault energy (SFE) of the alloy prior to conducting the mechanical test in this research. Subsequently, transmission electron microscopy (TEM) is employed to measure the widths of partial dislocation in specimens subject to tensile testing, enabling the determination of the SFE in the CoCrCuNiSi medium-entropy alloy. The alloys are prepared with small quantities of silicon to investigate its effects on SFE, specifically in three face-centered cubic low SFE alloys. The parameters necessary for SFE calculations are determined by digital image correlation to gain Poisson's ratio and nanoindentation to determine Young's modules. Furthermore, the subsequent mechanical property evaluations are performed to corroborate the precision of both measurements. Observations of the deformed microstructure using electron backscatter diffraction and TEM revealed that the reduction in SFE promotes the mechanisms of twinning-induced plasticity and transformation-induced plasticity effects, thereby contributing to an enhancement in the alloy's strength. The findings substantiate the correlation between SFE and the deformation mechanisms, highlighting the potential for optimizing alloy properties through the addition of minor elements. [Display omitted] •The incorporation of silicon reduces the stacking fault energy, thereby promoting TWIP and TRIP.•XRD peak shifts were utilized to estimate SFE, and these were corroborated by TEM, ensuring accuracy and reliability.•The study elucidated the deformation mechanisms from TWIP to TRIP as SFE decreases, dictating mechanical properties.

: Si-induced stacking fault energy modulation and its impact on deformation mechanisms in non-equimolar CoCrCuNi alloys
: Pin-Hua Chen - National Tsing Hua University
Ting-En Shen - National Tsing Hua University
Hsin-Chieh Jhou - National Tsing Hua University
Wei-Chen Hsu - National Tsing Hua University
Chong-Chi Chi - National Tsing Hua University
Ming-Yen Lu - National Tsing Hua University, College of Semiconductor Research
Jien-Wei Yeh - National Tsing Hua University, Department of Materials Science and Engineering
Che-Wei Tsai - National Tsing Hua University, Department of Materials Science and Engineering
: Elsevier Inc
: Journal article
: 11/2025
: Materials characterization, Vol.229, 115557
: English