Serrated flow of Al-Li single crystals was investigated under different aging conditions,temperatures(T)and strain rates(ε).The results show that dynamic strain aging(DSA)of solute Li atoms alone is not strong enough...Serrated flow of Al-Li single crystals was investigated under different aging conditions,temperatures(T)and strain rates(ε).The results show that dynamic strain aging(DSA)of solute Li atoms alone is not strong enough to make the serrated flow at solid solution state.The occurrence of the serrated flow is related to the shearing ofδ'particles.Critical strain of serration can change normally or inversely with T and e,which indicates the serration in Al-Li alloys is a thermally activated process.A proposed mechanism for the occurrence of the serration is that mobile dislocations are pinned when they cross the shearedδ'particles that might be dissolved during deformation,thus induce the serrated flow in the Al-Li single crystal.展开更多
目的对基于决策需求评估工作手册进行需求评估的相关研究进行范围综述,为国内开展相关研究提供参考。方法采用澳大利亚乔安娜布里格斯研究所范围综述指南为方法学框架,检索PubMed、Web of Science、Embase、CINAHL、中国知网、万方数据...目的对基于决策需求评估工作手册进行需求评估的相关研究进行范围综述,为国内开展相关研究提供参考。方法采用澳大利亚乔安娜布里格斯研究所范围综述指南为方法学框架,检索PubMed、Web of Science、Embase、CINAHL、中国知网、万方数据库、维普网和中国生物医学文献数据库,检索时限为建库至2023年3月31日。结果共纳入12篇文献,对纳入文献的基本信息、研究目的、研究类型、研究对象、收集方法、评估指导工具、结果等进行总结和分析。结论未来医护人员利用工作手册进行需求评估时,注意全面纳入工作手册的核心要素,从配偶、病友等多角度评估患者的决策需求,根据需求评估的结果开发或利用现有的患者决策辅助系统为患者提供决策支持,提高共享决策的质量。展开更多
This article studies the phase transformation of the metastable β-Ti-A1-Mo-V-Cr-Zr alloy （Ti-1300） to disclose the morphological reason for its high strength and high fracture toughness. It has been found that its ...This article studies the phase transformation of the metastable β-Ti-A1-Mo-V-Cr-Zr alloy （Ti-1300） to disclose the morphological reason for its high strength and high fracture toughness. It has been found that its ultrahigh strength （ultimate tensile strength exceeds 1 400 MPa） owes mainly to the spheroidization of the α-phase, while the high fracture toughness （exceeds 81 MPa·m^1/2） to the special lath-shaped α-particles. Compared to the needle-shaped second α-articles, the coarser lath-shaped ones remove the stress concentration at the lath tips and consequently benefit improvement of fracture toughness. The article also describes shape evolution of the α-particles during aging thermodynamically and kinetically, and suggests an optimized aging processing to achieve an ideal balance between high strength and high toughness for this alloy.展开更多
基金Supported by the National Natural Science Foundation of China。
文摘Serrated flow of Al-Li single crystals was investigated under different aging conditions,temperatures(T)and strain rates(ε).The results show that dynamic strain aging(DSA)of solute Li atoms alone is not strong enough to make the serrated flow at solid solution state.The occurrence of the serrated flow is related to the shearing ofδ'particles.Critical strain of serration can change normally or inversely with T and e,which indicates the serration in Al-Li alloys is a thermally activated process.A proposed mechanism for the occurrence of the serration is that mobile dislocations are pinned when they cross the shearedδ'particles that might be dissolved during deformation,thus induce the serrated flow in the Al-Li single crystal.
文摘目的对基于决策需求评估工作手册进行需求评估的相关研究进行范围综述,为国内开展相关研究提供参考。方法采用澳大利亚乔安娜布里格斯研究所范围综述指南为方法学框架,检索PubMed、Web of Science、Embase、CINAHL、中国知网、万方数据库、维普网和中国生物医学文献数据库,检索时限为建库至2023年3月31日。结果共纳入12篇文献,对纳入文献的基本信息、研究目的、研究类型、研究对象、收集方法、评估指导工具、结果等进行总结和分析。结论未来医护人员利用工作手册进行需求评估时,注意全面纳入工作手册的核心要素,从配偶、病友等多角度评估患者的决策需求,根据需求评估的结果开发或利用现有的患者决策辅助系统为患者提供决策支持,提高共享决策的质量。
基金National Basic Research Program of China (2007CB613805)
文摘This article studies the phase transformation of the metastable β-Ti-A1-Mo-V-Cr-Zr alloy （Ti-1300） to disclose the morphological reason for its high strength and high fracture toughness. It has been found that its ultrahigh strength （ultimate tensile strength exceeds 1 400 MPa） owes mainly to the spheroidization of the α-phase, while the high fracture toughness （exceeds 81 MPa·m^1/2） to the special lath-shaped α-particles. Compared to the needle-shaped second α-articles, the coarser lath-shaped ones remove the stress concentration at the lath tips and consequently benefit improvement of fracture toughness. The article also describes shape evolution of the α-particles during aging thermodynamically and kinetically, and suggests an optimized aging processing to achieve an ideal balance between high strength and high toughness for this alloy.
