To investigate dynamic tensile and compressive properties of AT72 magnesium alloys under high strain rates,the Split Hopkinson tensile Bar(SHTB)and the Split Hopkinson Pressure Bar apparatus was used at ambient temper...To investigate dynamic tensile and compressive properties of AT72 magnesium alloys under high strain rates,the Split Hopkinson tensile Bar(SHTB)and the Split Hopkinson Pressure Bar apparatus was used at ambient temperature.The specimens after dynamic tension and dynamic compression were analyzed by scanning electron microscope(SEM)and metallographic microscope.Dynamic mechanical properties and fracture mechanism were discussed in this paper.The results show that at approximate tensile strain rate,the dynamic tensile strength of ordinary die-casting AT72 and vacuum die-casting AT72 is very similar,but the dynamic failure strain is of great difference.AT72 magnesium alloys under dynamic compressive yield continuously,and have the slight positive strain rate effect.The dynamic compressive behaviors of ordinary die-casting AT72 and vacuum die-casting AT72 are nearly the same.The dynamic tensile fracture mechanism of both vacuum die-casting AT72 and ordinary die-casting AT72 is inter-granular fracture.The dynamic compressive fracture mechanism of both vacuum die-casting AT72 and ordinary die-casting AT72 is quasi-cleavage intra-crystalline failure.The pores have an important effect on dynamic properties of die casting magnesium alloys.展开更多
NAN Rendong,a distinguished expert in radio astronomy who is known as the father of the world’s largest radio telescope,died from lung cancer in Boston on September 15,2017 at the age of 72.His untimely passing away ...NAN Rendong,a distinguished expert in radio astronomy who is known as the father of the world’s largest radio telescope,died from lung cancer in Boston on September 15,2017 at the age of 72.His untimely passing away was just ten days before his masterpiece,the Five-hundred-meter Aperture Spherical radio Telescope(FAST),which he spent over two decades conceiving and building for the next generation展开更多
基金The authors would like to acknowledge the financial support from the Ministry of Science and Technology of People’s Republic of China(National Basic Research Program of China,No:2011BAE22B05,Research and evaluation of magnesium alloy protection,connectivity and reliability)a Specialized Research Fund of the Doctoral Program of colleges and universities,No:20122102110002,Research of local deformation and fracture mechanism of AZ31 Magnesium alloy under high speed impact.
文摘To investigate dynamic tensile and compressive properties of AT72 magnesium alloys under high strain rates,the Split Hopkinson tensile Bar(SHTB)and the Split Hopkinson Pressure Bar apparatus was used at ambient temperature.The specimens after dynamic tension and dynamic compression were analyzed by scanning electron microscope(SEM)and metallographic microscope.Dynamic mechanical properties and fracture mechanism were discussed in this paper.The results show that at approximate tensile strain rate,the dynamic tensile strength of ordinary die-casting AT72 and vacuum die-casting AT72 is very similar,but the dynamic failure strain is of great difference.AT72 magnesium alloys under dynamic compressive yield continuously,and have the slight positive strain rate effect.The dynamic compressive behaviors of ordinary die-casting AT72 and vacuum die-casting AT72 are nearly the same.The dynamic tensile fracture mechanism of both vacuum die-casting AT72 and ordinary die-casting AT72 is inter-granular fracture.The dynamic compressive fracture mechanism of both vacuum die-casting AT72 and ordinary die-casting AT72 is quasi-cleavage intra-crystalline failure.The pores have an important effect on dynamic properties of die casting magnesium alloys.
文摘NAN Rendong,a distinguished expert in radio astronomy who is known as the father of the world’s largest radio telescope,died from lung cancer in Boston on September 15,2017 at the age of 72.His untimely passing away was just ten days before his masterpiece,the Five-hundred-meter Aperture Spherical radio Telescope(FAST),which he spent over two decades conceiving and building for the next generation
