Shock compression and spallation damage of a face-center cubic phase high-entropy alloy(HEA)Al_(0.1)CoCrFeNi were investigated via plate impact experiments along with free surface velocity measurements.Postmortem samp...Shock compression and spallation damage of a face-center cubic phase high-entropy alloy(HEA)Al_(0.1)CoCrFeNi were investigated via plate impact experiments along with free surface velocity measurements.Postmortem samples were characterized with transmission electron microscopy and electron backscatter diffraction.The Hugoniot equation of state and spall strength at different impact strengths were determined.There exists a power-law relation between spall strength and strain rate.The spall strength of Al_(0.1)CoCrFeNi HEA is about 50%higher than those of previously studied HEAs and comparable to those widely applied structural stainless steels at the same shock stress.Dislocation glide and stacking faults are the important deformation mechanisms in the Al_(0.1)CoCrFeNi HEA.Nanotwins are only observed at high shock stress.Damage in the Al_(0.1)CoCrFeNi HEA is ductile in nature.Voids are nucleated preferentially in grain interiors,and the intragranular voids show a strong dependence on grain boundary misorientation and peak stress.展开更多
Shock compression and spallation of a eutectic high-entropy alloy(HEA)AlCoCrFeNi_(2.1)with lamellar structure are investigated via plate impact loading with free-surface velocity measurements.The as-cast and postmorte...Shock compression and spallation of a eutectic high-entropy alloy(HEA)AlCoCrFeNi_(2.1)with lamellar structure are investigated via plate impact loading with free-surface velocity measurements.The as-cast and postmortem samples are characterized with transmission electron microscopy,electron back-scatter diffraction and scanning electron microscopy.An accurate Hugoniot equation of state is determined.Af-ter shock compression to∼12 GPa,both the L1_(2)and B_(2)phases retain their ordered structures.Dense dislocations in the{111}slip planes,stacking faults and deformation twins are found in the L1_(2)phase,along with fewer dislocations in the{110}slip bands in the B(2)phase.Shock-induced deformation twin-ning within the L1_(2)phase of this HEA is observed as a new deformation mechanism under various load-ing conditions.For spallation,both ductile and brittle damage modes are observed.The micro voids and cracks prefer to nucleate at the phase boundaries chiefly,then in the B(2)phase.Under similar shock stress,the spall strength of AlCoCrFeNi_(2.1)HEA is about 40%higher than those of other reported dual-phase HEAs due to the high stability of its semi-coherent phase boundaries.展开更多
基金financially supported in part by the Sichuan Province Key R&D Program(No.2022YFG0033)the National Natural Science Foundation of China(Nos.11627901 and11902274)。
文摘Shock compression and spallation damage of a face-center cubic phase high-entropy alloy(HEA)Al_(0.1)CoCrFeNi were investigated via plate impact experiments along with free surface velocity measurements.Postmortem samples were characterized with transmission electron microscopy and electron backscatter diffraction.The Hugoniot equation of state and spall strength at different impact strengths were determined.There exists a power-law relation between spall strength and strain rate.The spall strength of Al_(0.1)CoCrFeNi HEA is about 50%higher than those of previously studied HEAs and comparable to those widely applied structural stainless steels at the same shock stress.Dislocation glide and stacking faults are the important deformation mechanisms in the Al_(0.1)CoCrFeNi HEA.Nanotwins are only observed at high shock stress.Damage in the Al_(0.1)CoCrFeNi HEA is ductile in nature.Voids are nucleated preferentially in grain interiors,and the intragranular voids show a strong dependence on grain boundary misorientation and peak stress.
基金sponsored in part by Sichuan Province Key R&D Program(No.2022YFG0033)the National Natural Science Foundation of China(Nos.12102491,52101150,11902274,11627901).
文摘Shock compression and spallation of a eutectic high-entropy alloy(HEA)AlCoCrFeNi_(2.1)with lamellar structure are investigated via plate impact loading with free-surface velocity measurements.The as-cast and postmortem samples are characterized with transmission electron microscopy,electron back-scatter diffraction and scanning electron microscopy.An accurate Hugoniot equation of state is determined.Af-ter shock compression to∼12 GPa,both the L1_(2)and B_(2)phases retain their ordered structures.Dense dislocations in the{111}slip planes,stacking faults and deformation twins are found in the L1_(2)phase,along with fewer dislocations in the{110}slip bands in the B(2)phase.Shock-induced deformation twin-ning within the L1_(2)phase of this HEA is observed as a new deformation mechanism under various load-ing conditions.For spallation,both ductile and brittle damage modes are observed.The micro voids and cracks prefer to nucleate at the phase boundaries chiefly,then in the B(2)phase.Under similar shock stress,the spall strength of AlCoCrFeNi_(2.1)HEA is about 40%higher than those of other reported dual-phase HEAs due to the high stability of its semi-coherent phase boundaries.
