Premature adiabatic shear localization caused by strain softening is a roadblock for the application of body-centered cubic(BCC)structured high-entropy alloy(HEAs)in the impact field.A micron-scale orthorhombic-phase(...Premature adiabatic shear localization caused by strain softening is a roadblock for the application of body-centered cubic(BCC)structured high-entropy alloy(HEAs)in the impact field.A micron-scale orthorhombic-phase(O-phase)strengthened TiZrVNbAl alloy was developed to delay adiabatic shear failure and enhance dynamic ductility.The O-phase can not only reduce the slip length,but also promote the pinning and tangling of the dislocations near the phase boundaries.The introduction of the O-phase transformed the strain hardening rate from negative to positive,resulting in a significantly improved dynamic shear resistance.Meanwhile,slip transfer across the O-phase via dislocation cutting mechanisms and a reduction of slip band spacing guaranteed dynamic deformation uniformity.Benefiting from the introduction of the O-phase,the alloy exhibits an excellent stored energy density(∼446 J/cm^(3),surpass the reported BCC-HEAs and typical titanium alloys),a large dynamic fracture strain(∼42%)and a considerable dynamic specific yield strength(∼241 MPa cm^(3)g^(-1)).The present study presents an effective approach for developing BCC-HEAs with excellent dynamic shear resistance and plasticity.展开更多
基金supported by the YEQISUN Joint Funds of the National Natural Science Foundation of China(Grant No.U2241234)the National Natural Science Foundation of China(Grant No.52301127).
文摘Premature adiabatic shear localization caused by strain softening is a roadblock for the application of body-centered cubic(BCC)structured high-entropy alloy(HEAs)in the impact field.A micron-scale orthorhombic-phase(O-phase)strengthened TiZrVNbAl alloy was developed to delay adiabatic shear failure and enhance dynamic ductility.The O-phase can not only reduce the slip length,but also promote the pinning and tangling of the dislocations near the phase boundaries.The introduction of the O-phase transformed the strain hardening rate from negative to positive,resulting in a significantly improved dynamic shear resistance.Meanwhile,slip transfer across the O-phase via dislocation cutting mechanisms and a reduction of slip band spacing guaranteed dynamic deformation uniformity.Benefiting from the introduction of the O-phase,the alloy exhibits an excellent stored energy density(∼446 J/cm^(3),surpass the reported BCC-HEAs and typical titanium alloys),a large dynamic fracture strain(∼42%)and a considerable dynamic specific yield strength(∼241 MPa cm^(3)g^(-1)).The present study presents an effective approach for developing BCC-HEAs with excellent dynamic shear resistance and plasticity.
