Deformation-induced HCP phase transformation of CrCoNiSi0.3 medium-entropy alloy under high strain rate tension

The yield strength of a CrCoNiSi0.3 medium-entropy alloy is significantly increased from 450 MPa (quasi-static, 0.001 s−1) to 1600 MPa (at a strain rate of 5000 s−1) under dynamic tension, with a considerable ductility of 60%. The high strain-rate sensitivity (SRS) of strength and work hardening is...

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Veröffentlicht in:Applied physics letters 2024-04, Vol.124 (14)
Hauptverfasser: Chang, Hui, Zhang, Tuanwei, Qiao, Junwei, Liaw, Peter K., Jiao, Zhiming, Li, Zhiqiang, Quan, Long, Wang, Zhihua
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Sprache:eng
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Zusammenfassung:The yield strength of a CrCoNiSi0.3 medium-entropy alloy is significantly increased from 450 MPa (quasi-static, 0.001 s−1) to 1600 MPa (at a strain rate of 5000 s−1) under dynamic tension, with a considerable ductility of 60%. The high strain-rate sensitivity (SRS) of strength and work hardening is obtained, and the strength SRS reaches 0.408. The dominant deformation mechanisms are abundant multiple-twinning, increasing fractions of deformation twins and phase transformation from face-centered-cubic to hexagonal-close-packed (HCP) phases with a strain rate. A universal dislocation-hardened constitutive model considering the evolution of the twin and HCP transformation is established to predict the flow stress and microstructure evolution.
ISSN:0003-6951
1077-3118
DOI:10.1063/5.0202924