By means of statistical analysis,the deformation mechanisms taking place in elastic loading and plastic shearing stages during serrated flows on the stress-strain curves for bulk metallic glasses were studied comprehe...By means of statistical analysis,the deformation mechanisms taking place in elastic loading and plastic shearing stages during serrated flows on the stress-strain curves for bulk metallic glasses were studied comprehensively.Normalized serration number presented a linear increasing tendency with the decrease of applied strain rates due to the reduction of free volumes.An excellent plastic deformation was illustrated from the influences of structure arrangement with activation energy.By using mean-field theory（MFT）,maximum elastic-energy density at different strain rates could be predicted by MFT besides maximum stress drops during serrations.These results were helpful for understanding the serrated flow behavior or designing decent schemes to improve the plasticity of bulk metallic glasses at room temperature.展开更多
Intermittent serrated flows of a novel ductile Fe60Ni20P13C7 bulk metallic glass（BMG）at variant strain rates were investigated by statistics analysis.Peak and clutter distribution of slip-avalanche magnitudes are di...Intermittent serrated flows of a novel ductile Fe60Ni20P13C7 bulk metallic glass（BMG）at variant strain rates were investigated by statistics analysis.Peak and clutter distribution of slip-avalanche magnitudes are displayed during stable plastic flows at strain rates of 2×10-4 s-1 and 5×10-5 s-1,respectively,which means that serration behavior depends on the strain rate.However,the remarkable agreement between measured slip-avalanche magnitudes and the scaling behavior,i.e.a universal complementary cumulative distribution function（CCDF）predicted by mean-field theory（MFT）model,indicates that the plasticity of the present Fe-based BMGs can be tuned by imposed strain rates：Smax^6）ε-λ.This tuned plasticity is elucidated with expended free-volume model.Moreover,the scaling behavior of serrated flows for other strain rates can be predicted as well.展开更多
The metallic glass matrix composites（MGMCs）and bulk metallic glasses（BMGs）were studied by statistical analysis during plastic deformation at the strain rates of 2×10^-2,2×10^-3,and 2×10^-4 s^-1,resp...The metallic glass matrix composites（MGMCs）and bulk metallic glasses（BMGs）were studied by statistical analysis during plastic deformation at the strain rates of 2×10^-2,2×10^-3,and 2×10^-4 s^-1,respectively.No serration events occur in both MGMCs and BMGs during compression tests at the strain rate of 2×10^-2 s^-1.When deformed at the strain rate of 2×10^-3 s^-1,the BMG displays a larger plasticity,which is due to the larger serration events followed by a series of small serrations caused by the continuous movement of free volume.The amplitudes and elastic-energy densities increase with increasing the strain rates owing to many serrations in MGMCs.It is deduced that the Young′s modulus decreases from the normalized stress drop and fluctuations are observed on stressstrain curves,which is attributed to a lower coefficient according to the stick-slip model.展开更多
基金supported by the National Natural Science Foundation of China(No.21473175 and No.21273215)the National Key Basic Research Program of China from the Ministry of Science andTechnology of China(No.2015CB932301)
基金the financial support of National Natural Science Foundation of China(No.51371122)the Youth Natural Science Foundation of Shanxi Province,China(No.2015021005)
文摘By means of statistical analysis,the deformation mechanisms taking place in elastic loading and plastic shearing stages during serrated flows on the stress-strain curves for bulk metallic glasses were studied comprehensively.Normalized serration number presented a linear increasing tendency with the decrease of applied strain rates due to the reduction of free volumes.An excellent plastic deformation was illustrated from the influences of structure arrangement with activation energy.By using mean-field theory（MFT）,maximum elastic-energy density at different strain rates could be predicted by MFT besides maximum stress drops during serrations.These results were helpful for understanding the serrated flow behavior or designing decent schemes to improve the plasticity of bulk metallic glasses at room temperature.
基金the financial support of National Natural Science Foundation of China(No.51371122)the financial support of National Natural Science Foundation of China(No.51501220)+1 种基金the Youth Natural Science Foundation of Shanxi Province,China(No.2015021005)the Natural Science Foundation of Jiangsu Province(BK20150170)
文摘Intermittent serrated flows of a novel ductile Fe60Ni20P13C7 bulk metallic glass（BMG）at variant strain rates were investigated by statistics analysis.Peak and clutter distribution of slip-avalanche magnitudes are displayed during stable plastic flows at strain rates of 2×10-4 s-1 and 5×10-5 s-1,respectively,which means that serration behavior depends on the strain rate.However,the remarkable agreement between measured slip-avalanche magnitudes and the scaling behavior,i.e.a universal complementary cumulative distribution function（CCDF）predicted by mean-field theory（MFT）model,indicates that the plasticity of the present Fe-based BMGs can be tuned by imposed strain rates：Smax^6）ε-λ.This tuned plasticity is elucidated with expended free-volume model.Moreover,the scaling behavior of serrated flows for other strain rates can be predicted as well.
基金Item Sponsored by National Natural Science Foundation of China(51371122,51471025,51210105006)Program for Innovative Talents of Higher Learning Institutions of Shanxi of China(2013)Youth Natural Science Foundation of Shanxi Province of China(2015021005)
文摘The metallic glass matrix composites（MGMCs）and bulk metallic glasses（BMGs）were studied by statistical analysis during plastic deformation at the strain rates of 2×10^-2,2×10^-3,and 2×10^-4 s^-1,respectively.No serration events occur in both MGMCs and BMGs during compression tests at the strain rate of 2×10^-2 s^-1.When deformed at the strain rate of 2×10^-3 s^-1,the BMG displays a larger plasticity,which is due to the larger serration events followed by a series of small serrations caused by the continuous movement of free volume.The amplitudes and elastic-energy densities increase with increasing the strain rates owing to many serrations in MGMCs.It is deduced that the Young′s modulus decreases from the normalized stress drop and fluctuations are observed on stressstrain curves,which is attributed to a lower coefficient according to the stick-slip model.
