The influence of Hf on the precipitation behavior of γ'phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated.The results reveal that the addition of Hf ...The influence of Hf on the precipitation behavior of γ'phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated.The results reveal that the addition of Hf increases the average diameter ofγ'phases after thermal exposure at 700℃ for 5000 h,which enhances the critical resolved shear stress required for dislocations to shear the γ'phases in the Ni-Cr-Mo alloy.Simultaneously,element Hf incorporated into the γ'phases increases the lattice mismatch between the γ'and γ phase,thereby strengthening the coherency strengthening effect.These two factors collectively contribute to the enhanced strength of the alloy.Thus,Hf alloying effectively improves the yield strength of the Ni-Cr-Mo alloy after thermal exposure at 700℃.展开更多
High-entropy alloys,a novel class of materials characterized by the statistical distribution of multiple principal elements on simple crystalline lattices,have emerged as a research hotspot in materials science and co...High-entropy alloys,a novel class of materials characterized by the statistical distribution of multiple principal elements on simple crystalline lattices,have emerged as a research hotspot in materials science and condensed matter physics due to their exceptional mechanical properties and unique high-entropy characteristic.Since the discovery of the first high-entropy superconductor in 2014,exploring their superconducting performance and advantages has progressively become a frontier in scientific research.The Ta-Nb-Hf-Zr-Ti system,in particular,exhibits remarkable mechanical robustness,outstanding radiation tolerance,and superconducting performance comparable to the binary NbTi alloy,positioning it as a promising candidate for advanced applications,such as high-field superconducting magnets,superconducting electric motors,and next-generation nuclear fusion reactors.This review systematically summarized global research progress on Ta-Nb-Hf-Zr-Ti-based superconductors,aiming to provide a comprehensive reference for advancing this burgeoning field.展开更多
Hafnia-based ferroelectrics have emerged as promising materials for next-generation nanoelectronics owing to their robust nanoscale properties and compatibility with metal-oxide-semiconductor technology.However,their ...Hafnia-based ferroelectrics have emerged as promising materials for next-generation nanoelectronics owing to their robust nanoscale properties and compatibility with metal-oxide-semiconductor technology.However,their metastable nature remains a key challenge for practical implementation.Utilizing scanning transmission electron microscopy,we investigated the atomic-scale mechanisms governing ferroelectric transitions and the metastability of polar phases in 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2)thin films.Our results demonstrate that oxygen vacancies,coupled with rhombohedral distortions of the cation lattice,facilitate ferroelectric phase transitions and enable robust polar switching through adaptive processes,including cell-by-cell oxygen displacement and domain-wall-mediated nucleation and growth.These findings underscore the pivotal role of oxygen vacancies and lattice distortions in stabilizing polar phases and provide detailed insights into the atomic structures and transition dynamics of polymorphic Hf_(0.5)Zr_(0.5)O_(2-x),thereby advancing its potential for practical device applications.展开更多
基金National Key Research and Development Program of China(2021YFB3704103)National Natural Science Foundation of China(51571191)。
文摘The influence of Hf on the precipitation behavior of γ'phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated.The results reveal that the addition of Hf increases the average diameter ofγ'phases after thermal exposure at 700℃ for 5000 h,which enhances the critical resolved shear stress required for dislocations to shear the γ'phases in the Ni-Cr-Mo alloy.Simultaneously,element Hf incorporated into the γ'phases increases the lattice mismatch between the γ'and γ phase,thereby strengthening the coherency strengthening effect.These two factors collectively contribute to the enhanced strength of the alloy.Thus,Hf alloying effectively improves the yield strength of the Ni-Cr-Mo alloy after thermal exposure at 700℃.
基金Northwest Institute of Nonferrous Metal Research Funding(YK2324)Key Research and Development Program of Shaanxi(2024GX-YBXM-403)National Natural Science Foundation of China(52277029)。
文摘High-entropy alloys,a novel class of materials characterized by the statistical distribution of multiple principal elements on simple crystalline lattices,have emerged as a research hotspot in materials science and condensed matter physics due to their exceptional mechanical properties and unique high-entropy characteristic.Since the discovery of the first high-entropy superconductor in 2014,exploring their superconducting performance and advantages has progressively become a frontier in scientific research.The Ta-Nb-Hf-Zr-Ti system,in particular,exhibits remarkable mechanical robustness,outstanding radiation tolerance,and superconducting performance comparable to the binary NbTi alloy,positioning it as a promising candidate for advanced applications,such as high-field superconducting magnets,superconducting electric motors,and next-generation nuclear fusion reactors.This review systematically summarized global research progress on Ta-Nb-Hf-Zr-Ti-based superconductors,aiming to provide a comprehensive reference for advancing this burgeoning field.
基金supported by the National Natural Science Foundation of China (Grant Nos.12334001,52461160301,52322311,52427802,12222414)the National Key R&D Program of China (Grant Nos.2024YFA1208201,2021YFA1400500,2021YFA1400204)the Youth Innovation Promotion Association of the CAS (Grant Nos.Y2022003 and 2020009)。
文摘Hafnia-based ferroelectrics have emerged as promising materials for next-generation nanoelectronics owing to their robust nanoscale properties and compatibility with metal-oxide-semiconductor technology.However,their metastable nature remains a key challenge for practical implementation.Utilizing scanning transmission electron microscopy,we investigated the atomic-scale mechanisms governing ferroelectric transitions and the metastability of polar phases in 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2)thin films.Our results demonstrate that oxygen vacancies,coupled with rhombohedral distortions of the cation lattice,facilitate ferroelectric phase transitions and enable robust polar switching through adaptive processes,including cell-by-cell oxygen displacement and domain-wall-mediated nucleation and growth.These findings underscore the pivotal role of oxygen vacancies and lattice distortions in stabilizing polar phases and provide detailed insights into the atomic structures and transition dynamics of polymorphic Hf_(0.5)Zr_(0.5)O_(2-x),thereby advancing its potential for practical device applications.
