The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
J W Qiao - One of the best experts on this subject based on the ideXlab platform.
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serrated Flow Kinetics in a zr based bulk metallic glass
Intermetallics, 2010Co-Authors: J W Qiao, Yong Zhang, P K LiawAbstract:Abstract At different strain rates, the stress-Flow serrations in the compressive stress-time curves of a Zr-based bulk metallic glass (BMG) exhibit different magnitudes and time scales. A critical strain rate can be identified, at which the serrated Flow Kinetics is characterized to be homogeneous in both time and magnitude. Below the critical strain rate, the serrations are lack of homogeneous magnitudes and time scales because the excessive elastic energy results in distinct softening within the viscous fluid-like shearing layer due to the adiabatic heating. As a consequence, the tiny disturbances, such as the vibration of test machines, affect the shear banding behavior. A periodic function is established for the critical instability, and two pertinent parameters, the mean stress drop magnitude and the mean waiting time (MWT), can be determined, which may be associated with the deformation micromechanism, the mechanical property, and the glass-forming ability of BMGs. The present approach may provide a new way to study the serration-deformation behavior of BMGs.
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Jerky-Flow characteristics for a Zr-based bulk metallic glass
Scripta Materialia, 2010Co-Authors: J W Qiao, P K Liaw, Fuqian Yang, Gongyao Wang, Yong ZhangAbstract:The jerky Flow for a Zr-based bulk metallic glass is analyzed, based on the accumulation and dissipation of the elastic energy, and the temperature rise within the shear bands. The formation of a viscous layer results in the tiny disturbance among the jerky Flows, which makes the jerky-Flow Kinetics inhomogeneous. The parameter, the jerky-drop-stressing speed, is used to characterize the shear-banding Kinetics. An increased shear-banding speed dominates upon loading, which is in agreement with the change of the free volume.
P K Liaw - One of the best experts on this subject based on the ideXlab platform.
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serrated Flow Kinetics in a zr based bulk metallic glass
Intermetallics, 2010Co-Authors: J W Qiao, Yong Zhang, P K LiawAbstract:Abstract At different strain rates, the stress-Flow serrations in the compressive stress-time curves of a Zr-based bulk metallic glass (BMG) exhibit different magnitudes and time scales. A critical strain rate can be identified, at which the serrated Flow Kinetics is characterized to be homogeneous in both time and magnitude. Below the critical strain rate, the serrations are lack of homogeneous magnitudes and time scales because the excessive elastic energy results in distinct softening within the viscous fluid-like shearing layer due to the adiabatic heating. As a consequence, the tiny disturbances, such as the vibration of test machines, affect the shear banding behavior. A periodic function is established for the critical instability, and two pertinent parameters, the mean stress drop magnitude and the mean waiting time (MWT), can be determined, which may be associated with the deformation micromechanism, the mechanical property, and the glass-forming ability of BMGs. The present approach may provide a new way to study the serration-deformation behavior of BMGs.
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Jerky-Flow characteristics for a Zr-based bulk metallic glass
Scripta Materialia, 2010Co-Authors: J W Qiao, P K Liaw, Fuqian Yang, Gongyao Wang, Yong ZhangAbstract:The jerky Flow for a Zr-based bulk metallic glass is analyzed, based on the accumulation and dissipation of the elastic energy, and the temperature rise within the shear bands. The formation of a viscous layer results in the tiny disturbance among the jerky Flows, which makes the jerky-Flow Kinetics inhomogeneous. The parameter, the jerky-drop-stressing speed, is used to characterize the shear-banding Kinetics. An increased shear-banding speed dominates upon loading, which is in agreement with the change of the free volume.
Frances M Ross - One of the best experts on this subject based on the ideXlab platform.
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step Flow Kinetics in nanowire growth
Physical Review Letters, 2010Co-Authors: J Tersoff, M C Reuter, Eric A Stach, Frances M RossAbstract:: Nanowire growth occurs by step Flow at the wire-catalyst interface, with strikingly different step-Flow Kinetics for solid versus liquid catalysts. Here we report quantitative in situ measurements of step Flow together with a kinetic model that reproduces the behavior. This allows us to identify the key parameters controlling step-Flow growth, evaluate changes in the catalyst composition during growth, and identify the most favorable conditions for growing abrupt heterojunctions in nanowires.
Yong Zhang - One of the best experts on this subject based on the ideXlab platform.
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serrated Flow Kinetics in a zr based bulk metallic glass
Intermetallics, 2010Co-Authors: J W Qiao, Yong Zhang, P K LiawAbstract:Abstract At different strain rates, the stress-Flow serrations in the compressive stress-time curves of a Zr-based bulk metallic glass (BMG) exhibit different magnitudes and time scales. A critical strain rate can be identified, at which the serrated Flow Kinetics is characterized to be homogeneous in both time and magnitude. Below the critical strain rate, the serrations are lack of homogeneous magnitudes and time scales because the excessive elastic energy results in distinct softening within the viscous fluid-like shearing layer due to the adiabatic heating. As a consequence, the tiny disturbances, such as the vibration of test machines, affect the shear banding behavior. A periodic function is established for the critical instability, and two pertinent parameters, the mean stress drop magnitude and the mean waiting time (MWT), can be determined, which may be associated with the deformation micromechanism, the mechanical property, and the glass-forming ability of BMGs. The present approach may provide a new way to study the serration-deformation behavior of BMGs.
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Jerky-Flow characteristics for a Zr-based bulk metallic glass
Scripta Materialia, 2010Co-Authors: J W Qiao, P K Liaw, Fuqian Yang, Gongyao Wang, Yong ZhangAbstract:The jerky Flow for a Zr-based bulk metallic glass is analyzed, based on the accumulation and dissipation of the elastic energy, and the temperature rise within the shear bands. The formation of a viscous layer results in the tiny disturbance among the jerky Flows, which makes the jerky-Flow Kinetics inhomogeneous. The parameter, the jerky-drop-stressing speed, is used to characterize the shear-banding Kinetics. An increased shear-banding speed dominates upon loading, which is in agreement with the change of the free volume.
J Tersoff - One of the best experts on this subject based on the ideXlab platform.
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step Flow Kinetics in nanowire growth
Physical Review Letters, 2010Co-Authors: J Tersoff, M C Reuter, Eric A Stach, Frances M RossAbstract:: Nanowire growth occurs by step Flow at the wire-catalyst interface, with strikingly different step-Flow Kinetics for solid versus liquid catalysts. Here we report quantitative in situ measurements of step Flow together with a kinetic model that reproduces the behavior. This allows us to identify the key parameters controlling step-Flow growth, evaluate changes in the catalyst composition during growth, and identify the most favorable conditions for growing abrupt heterojunctions in nanowires.