We report an enhanced rejuvenation in hot-drawn micrometer metallic glassy wires(MG wires)with the size reduction.Compared to metallic glasses(MGs)in bulk form,the modulus and hardness for the micro-scale MG wires,tes...We report an enhanced rejuvenation in hot-drawn micrometer metallic glassy wires(MG wires)with the size reduction.Compared to metallic glasses(MGs)in bulk form,the modulus and hardness for the micro-scale MG wires,tested by nanoindentation methods,are much lower and decrease with the decreasing size,with a maximum decrease of〜26%in modulus and^17%in hardness.This pronounced rejuvenation is evidenced by the larger sub-Tg relaxation enthalpy of the MG wires.The pronounced rejuvenation is physically related to the higher energy state induced by a combined effect of severely thermomechanical shearing and freezing the shear How into a constrained small-volume region.Our results reveal that the internal states and properties of MGs can be dramatically changed by a proper modulation of temperature,flow stress and size.展开更多
基金the National Key Research and Development Program of China under Grant Nos.2018YFA0703603,2017YFB0903902,and 2016YFB0300501the National Natural Science Foundation of China under Grant Nos.51822107,11790291,51671121,and 51761135125+2 种基金the National Natural Science Foundation of Guangdong Province under Grant No.2019B030302010the Key Research Program of Frontier Sciences(QYZDY-SSW-JSC017)the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No.XDB30000000.
文摘We report an enhanced rejuvenation in hot-drawn micrometer metallic glassy wires(MG wires)with the size reduction.Compared to metallic glasses(MGs)in bulk form,the modulus and hardness for the micro-scale MG wires,tested by nanoindentation methods,are much lower and decrease with the decreasing size,with a maximum decrease of〜26%in modulus and^17%in hardness.This pronounced rejuvenation is evidenced by the larger sub-Tg relaxation enthalpy of the MG wires.The pronounced rejuvenation is physically related to the higher energy state induced by a combined effect of severely thermomechanical shearing and freezing the shear How into a constrained small-volume region.Our results reveal that the internal states and properties of MGs can be dramatically changed by a proper modulation of temperature,flow stress and size.
