The hot deformation behavior and workability of pre-extruded ZK60A magnesium alloy were investigated by compression tests in the temperature range of 250-450 ℃and the strain rate range of 0.001-10 s 1. The constituti...The hot deformation behavior and workability of pre-extruded ZK60A magnesium alloy were investigated by compression tests in the temperature range of 250-450 ℃and the strain rate range of 0.001-10 s 1. The constitutive equation for the pre-extruded ZK60A alloy can be described by hyperbolic sine function. Processing maps were constructed from true strains of -0.2 to -0.8. The alloy experienced complete dynamic recrystallization （DRX） and showed good workability in the temperature range of 300-400 ℃ and the strain rate range of 0.01-0.001 s-Z, where hot working in pre-extruded ZK60A, such as forging, can be carried out. For large deformation to true strain of over -0.5, strain rates above 0.1 s-1 are not recommended at all temperatures, where flow instability such as local strain concentration, twinning deformation, abnormal grain growth, micro-cracks, and shear fracture were observed. Climb-controlled dislocation creep dominates both the plastic deformation and nucleation of DRX of the pre-extruded ZK60A magnesium alloy.展开更多
为了了解中国城市交通中车辆碰撞行人事故的形态,在中国长沙地区开展了深入的调查。共采集2001年至2006年期间行人事故案例497例,其中446例具有详细的事故信息,信息来源包括警察、医院和回勘调查。通过现场调查采集到51例行人事故。所...为了了解中国城市交通中车辆碰撞行人事故的形态,在中国长沙地区开展了深入的调查。共采集2001年至2006年期间行人事故案例497例,其中446例具有详细的事故信息,信息来源包括警察、医院和回勘调查。通过现场调查采集到51例行人事故。所有采集的事故数据被存档于长沙市深入的车辆交通事故调查数据库(IVAC)中。基于497例数据进行了统计分析,分析结果与瑞典STRADA(Swedish TRaffic Accident Data Acquisition)数据进行了对比研究。结果表明:长沙地区的行人死亡率高出瑞典2倍多,两个地区的大多数行人事故均发生在良好的照明条件和干燥气候条件下;与瑞典相比较,长沙的行人事故形态分布呈现出显著的不同。展开更多
基金Projects(51171113,51301107) supported by the National Natural Science Foundation of China
文摘The hot deformation behavior and workability of pre-extruded ZK60A magnesium alloy were investigated by compression tests in the temperature range of 250-450 ℃and the strain rate range of 0.001-10 s 1. The constitutive equation for the pre-extruded ZK60A alloy can be described by hyperbolic sine function. Processing maps were constructed from true strains of -0.2 to -0.8. The alloy experienced complete dynamic recrystallization （DRX） and showed good workability in the temperature range of 300-400 ℃ and the strain rate range of 0.01-0.001 s-Z, where hot working in pre-extruded ZK60A, such as forging, can be carried out. For large deformation to true strain of over -0.5, strain rates above 0.1 s-1 are not recommended at all temperatures, where flow instability such as local strain concentration, twinning deformation, abnormal grain growth, micro-cracks, and shear fracture were observed. Climb-controlled dislocation creep dominates both the plastic deformation and nucleation of DRX of the pre-extruded ZK60A magnesium alloy.
文摘为了了解中国城市交通中车辆碰撞行人事故的形态,在中国长沙地区开展了深入的调查。共采集2001年至2006年期间行人事故案例497例,其中446例具有详细的事故信息,信息来源包括警察、医院和回勘调查。通过现场调查采集到51例行人事故。所有采集的事故数据被存档于长沙市深入的车辆交通事故调查数据库(IVAC)中。基于497例数据进行了统计分析,分析结果与瑞典STRADA(Swedish TRaffic Accident Data Acquisition)数据进行了对比研究。结果表明:长沙地区的行人死亡率高出瑞典2倍多,两个地区的大多数行人事故均发生在良好的照明条件和干燥气候条件下;与瑞典相比较,长沙的行人事故形态分布呈现出显著的不同。
基金supported by the SJTU-GM Collaborative Research Laboratory Jointly Established by General Motors Global Research and Development(GM R&D)Research was Supported by National Key Research and Development Program of China(2016YFB0301000)+2 种基金Shanghai Rising-Star Program(15QB1402700)National Natural Science Foundation of China(NSFC)(51671128&51771113)Special Fund of Jiangsu Province(BA2016039).
