The new high-entropy metallic-glasses(HE-MGs)are designed by using Dy and Ho to replace Gd in Gd_(36)Tb_(20)Co_(20)Al_(24)alloy based on the binary eutectic clusters method.Compared with the equiatomic Gd 25 Tb 25 Co ...The new high-entropy metallic-glasses(HE-MGs)are designed by using Dy and Ho to replace Gd in Gd_(36)Tb_(20)Co_(20)Al_(24)alloy based on the binary eutectic clusters method.Compared with the equiatomic Gd 25 Tb 25 Co 25 Al 25 HE-MG,the non-equiatomic RE_(36)Tb_(20)Co_(20)Al_(24)(RE=Gd,Dy,or Ho)alloys show bet-ter glass-forming ability,which is attributed to the deep binary eutectic compositions used for alloy de-sign.All RE_(36)Tb_(20)Co_(20)Al_(24)alloys undergo second-order magnetic transition.An extreme peak value of magnetic entropy change is obtained as 10.3 J kg^(-1) K-1(5 T)for the Ho_(36)Tb_(20)Co_(20)Al_(24)alloy.In-situ high-energy synchrotron X-ray diffraction was conducted to observe the microstructural difference among non-equiatomic samples at cryogenic temperatures.The results indicate that Gd_(36)Tb_(20)Co_(20)Al_(24)alloy possesses a relatively large average value of the dispersion of local clusters at a low-temperature range.This,com-bined with the critical exponentβclose to 0.5 of Gd_(36)Tb_(20)Co_(20)Al_(24)alloy,leads to its widest working temperature span among non-equiatomic samples.This work successfully establishes the connection be-tween microstructure and magnetocaloric properties of HE-MGs,which is beneficial for understanding the physical mechanism of the magnetocaloric behaviors of HE-MGs.展开更多
A novel Ti/Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 composite was successfully prepared by infiltrating the melt into sintered Ti preform. It shows that the introduction of Ti particles into the composite results in an increase...A novel Ti/Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 composite was successfully prepared by infiltrating the melt into sintered Ti preform. It shows that the introduction of Ti particles into the composite results in an increase in elastic strain to 3% and an enhancement of the strength up to 2.1 GPa. High specific strength has been obtained because of the decrease in density of the composite. It is suggested that an improvement in the mechanical properties of the composite may be attributed to the generation of multiple shear bands and some deformation in the Ti particles.展开更多
Chaos has been well understood in dynamic system, however, how the chaotic behavior occur in jerky flow in material, is still not clear, and is lack of specific chaotic attractor. Here the jerky evolution of lateral f...Chaos has been well understood in dynamic system, however, how the chaotic behavior occur in jerky flow in material, is still not clear, and is lack of specific chaotic attractor. Here the jerky evolution of lateral force and the stair-like fluctuation of lateral displacement are observed for Ni62 Nb38(at.%) metallic glass film during nanoscratch process. This jerky flow is investigated by using the largest Lyapunov exponent, Kolmogorov entropy and fractal dimension, and chaotic behavior of lateral force-time and normal displacement-lateral displacement sequences is verified. In addition to time series analysis, it is found that jerk equation can be used to describe the jerky flow of the metallic-glass film during nanoscratch. More importantly, unambiguous chaotic attractor is presented by jerky dynamics using "jerk"-singularities, namely the total change rate of lateral force relative to scratch time. These reveal an inner connection between jerky flow and jerky dynamics in nanoscratch of a metallic-glass film.展开更多
基金financially supported by the National Natu-ral Science Foundation of China(Nos.52171154,51871076,and 51827801)Interdisciplinary Research Foundation of HIT(No.IR2021201)CGN-HIT Advanced Nuclear and New Energy Re-search Institute(No.CGN-HIT202209).
文摘The new high-entropy metallic-glasses(HE-MGs)are designed by using Dy and Ho to replace Gd in Gd_(36)Tb_(20)Co_(20)Al_(24)alloy based on the binary eutectic clusters method.Compared with the equiatomic Gd 25 Tb 25 Co 25 Al 25 HE-MG,the non-equiatomic RE_(36)Tb_(20)Co_(20)Al_(24)(RE=Gd,Dy,or Ho)alloys show bet-ter glass-forming ability,which is attributed to the deep binary eutectic compositions used for alloy de-sign.All RE_(36)Tb_(20)Co_(20)Al_(24)alloys undergo second-order magnetic transition.An extreme peak value of magnetic entropy change is obtained as 10.3 J kg^(-1) K-1(5 T)for the Ho_(36)Tb_(20)Co_(20)Al_(24)alloy.In-situ high-energy synchrotron X-ray diffraction was conducted to observe the microstructural difference among non-equiatomic samples at cryogenic temperatures.The results indicate that Gd_(36)Tb_(20)Co_(20)Al_(24)alloy possesses a relatively large average value of the dispersion of local clusters at a low-temperature range.This,com-bined with the critical exponentβclose to 0.5 of Gd_(36)Tb_(20)Co_(20)Al_(24)alloy,leads to its widest working temperature span among non-equiatomic samples.This work successfully establishes the connection be-tween microstructure and magnetocaloric properties of HE-MGs,which is beneficial for understanding the physical mechanism of the magnetocaloric behaviors of HE-MGs.
基金This study was financially supported by the National Natural Science Foundation of China (No.50431030, No.59871025, and No.50171006).
文摘A novel Ti/Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 composite was successfully prepared by infiltrating the melt into sintered Ti preform. It shows that the introduction of Ti particles into the composite results in an increase in elastic strain to 3% and an enhancement of the strength up to 2.1 GPa. High specific strength has been obtained because of the decrease in density of the composite. It is suggested that an improvement in the mechanical properties of the composite may be attributed to the generation of multiple shear bands and some deformation in the Ti particles.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51925103, 11771407, 51761135125, and 51671120)the China Postdoctoral Science Foundation (Grant No. 2019M651600)+1 种基金the Research Foundation for Advanced Talents of Henan University of Technology (Grant No. 2018BS027)the 111 Project (Grant No. D16002)
文摘Chaos has been well understood in dynamic system, however, how the chaotic behavior occur in jerky flow in material, is still not clear, and is lack of specific chaotic attractor. Here the jerky evolution of lateral force and the stair-like fluctuation of lateral displacement are observed for Ni62 Nb38(at.%) metallic glass film during nanoscratch process. This jerky flow is investigated by using the largest Lyapunov exponent, Kolmogorov entropy and fractal dimension, and chaotic behavior of lateral force-time and normal displacement-lateral displacement sequences is verified. In addition to time series analysis, it is found that jerk equation can be used to describe the jerky flow of the metallic-glass film during nanoscratch. More importantly, unambiguous chaotic attractor is presented by jerky dynamics using "jerk"-singularities, namely the total change rate of lateral force relative to scratch time. These reveal an inner connection between jerky flow and jerky dynamics in nanoscratch of a metallic-glass film.
