In-situ formed （Cu0.6Zr0.3Ti0.1）95Nb5 bulk metallic glass （BMG） composite with Nb-rich dendrite randomly dispersed in hard glassy matrix was prepared by casting into a water-cooled copper mold. The dendrite has mu...In-situ formed （Cu0.6Zr0.3Ti0.1）95Nb5 bulk metallic glass （BMG） composite with Nb-rich dendrite randomly dispersed in hard glassy matrix was prepared by casting into a water-cooled copper mold. The dendrite has much smaller hardness and elastic modulus than glassy matrix, and the stress concentration at interface provides a channel for the initiating and branching of shear bands upon loading, thus leading to a high compressive fracture strain of 6.08% and fracture strength about 2200 MPa. Comparing with other Cu-based BMG composite, the fracture strength of present （Cu0.6Zr0.3Ti0.1）95Nb5 composite is not significantly reduced, indicating that the addition of Nb in the current work is an effective and effortless way to fabricate new practical BMG composites with enhanced strength and good plasticity.展开更多
Mechanical properties of （Cu50Zr43Al7）100 Nbx （x=0,1,3,6,9） bulk metallic glasses rods with a diameter of 2.5 mm prepared by suction casting method were studied. The results of uniaxial compression tests at room t...Mechanical properties of （Cu50Zr43Al7）100 Nbx （x=0,1,3,6,9） bulk metallic glasses rods with a diameter of 2.5 mm prepared by suction casting method were studied. The results of uniaxial compression tests at room temperture show that the best mechanical properties of 2.8% and 1.98 GPa for plastic strain and fracture strength, respectively, in the sample with x=3. Microstructure, fracture surface and shear bands of the samples were observed by SEM and XRD methods.展开更多
The mechanical properties of the Zr52.5Cu17.9Ni14.6Al10Ti5 alloy were presented, with an emphasis on the strain rate effect and presence of crystalline inclusions on the deformation and fracture mechanisms. X-ray diff...The mechanical properties of the Zr52.5Cu17.9Ni14.6Al10Ti5 alloy were presented, with an emphasis on the strain rate effect and presence of crystalline inclusions on the deformation and fracture mechanisms. X-ray diffraction studies indicated fully amorphous alloy structures with lower oxygen contents and partial crystalline structures at higher oxygen levels;however, completely different compressive deformation behaviour was observed. Uniaxial compression tests of the fully amorphous alloy showed elastic deformation, followed by yielding, distinct plastic deformation and serration flow behaviour. An increase in strain rate from 1×10-4 to 1×10-2 s-1 did not affect the yield strength;however, it decreased the compressive fracture strength and reduced the plastic strain. Scanning electron microscopy (SEM) observations with energy dispersive spectroscopy (EDS) analysis showed that the intermetallic CuZr2 phase was present even in the low oxygen content alloy, leading to lower fracture strength and ductility loss. For the high oxygen level samples, the presence of the dendritic Zr51Cu28Al21 phase was confirmed, leading to fracture strength impairment. The difference between ductile and brittle samples has been reflected on the fracture surfaces. The higher the plastic strain was, the higher the density of shear bands forming during deformation manifested by a serration flow behaviour on stress-strain curves.展开更多
This paper presents methods for determining the basic geometry of end-gear with arc tooth external diameter, width of tooth, end module, number of teeth, pressure angle, tooth, tooth clearance parameters; at the same ...This paper presents methods for determining the basic geometry of end-gear with arc tooth external diameter, width of tooth, end module, number of teeth, pressure angle, tooth, tooth clearance parameters; at the same time gives the tooth bearing strength calculation method, and the formulas to calculate the tooth shear stress, surface stress and bolt fastening force of equivalent stress is established; finally write the software error simulation analysis.展开更多
Deformation of the bulk metallic glasses (BMGs) and the creation and propagation of the shear bands are closely interconnected.Shearing force was loaded on Zr 41.2 Ti 13.8 Cu 12.5 Ni 10.0 Be 22.5 (Vit.1) BMGs by cutti...Deformation of the bulk metallic glasses (BMGs) and the creation and propagation of the shear bands are closely interconnected.Shearing force was loaded on Zr 41.2 Ti 13.8 Cu 12.5 Ni 10.0 Be 22.5 (Vit.1) BMGs by cutting during the turning of the BMG rod.The temperature rise of alloy on the shear bands was calculated and the result showed that it could reach the temperature of the super-cooled liquid zone or exceed the melting point.The temperature rise caused viscous fluid flow and brought about the deformation of BMGs.This suggested that the deformation of BMGs was derived,at least to some extent,from the adiabatic shear temperature rise.展开更多
基金Project(51371149)supported by the National Natural Science Foundation of ChinaProject(151048)supported by the HUO Ying-dong Young Teacher Fund+4 种基金Project(2015ZF53066)supported by the Aeronautical Science Foundation of ChinaProject(92-QZ-2014)supported by the Free Research Fund of State Key Laboratory of Solidification Processing,ChinaProject(2015KJXX-10)supported by Shaanxi Young Stars of Science and Technology,ChinaProejct(2011CB610403)supported by the National Basic Research Program of ChinaProject(51125002)supported by the National Science Funds for Distinguished Young Scientists,China
文摘In-situ formed （Cu0.6Zr0.3Ti0.1）95Nb5 bulk metallic glass （BMG） composite with Nb-rich dendrite randomly dispersed in hard glassy matrix was prepared by casting into a water-cooled copper mold. The dendrite has much smaller hardness and elastic modulus than glassy matrix, and the stress concentration at interface provides a channel for the initiating and branching of shear bands upon loading, thus leading to a high compressive fracture strain of 6.08% and fracture strength about 2200 MPa. Comparing with other Cu-based BMG composite, the fracture strength of present （Cu0.6Zr0.3Ti0.1）95Nb5 composite is not significantly reduced, indicating that the addition of Nb in the current work is an effective and effortless way to fabricate new practical BMG composites with enhanced strength and good plasticity.
文摘Mechanical properties of （Cu50Zr43Al7）100 Nbx （x=0,1,3,6,9） bulk metallic glasses rods with a diameter of 2.5 mm prepared by suction casting method were studied. The results of uniaxial compression tests at room temperture show that the best mechanical properties of 2.8% and 1.98 GPa for plastic strain and fracture strength, respectively, in the sample with x=3. Microstructure, fracture surface and shear bands of the samples were observed by SEM and XRD methods.
基金supported by Ministry of Science and Higher Education Republic of Poland under contract No.11.11.110.299
文摘The mechanical properties of the Zr52.5Cu17.9Ni14.6Al10Ti5 alloy were presented, with an emphasis on the strain rate effect and presence of crystalline inclusions on the deformation and fracture mechanisms. X-ray diffraction studies indicated fully amorphous alloy structures with lower oxygen contents and partial crystalline structures at higher oxygen levels;however, completely different compressive deformation behaviour was observed. Uniaxial compression tests of the fully amorphous alloy showed elastic deformation, followed by yielding, distinct plastic deformation and serration flow behaviour. An increase in strain rate from 1×10-4 to 1×10-2 s-1 did not affect the yield strength;however, it decreased the compressive fracture strength and reduced the plastic strain. Scanning electron microscopy (SEM) observations with energy dispersive spectroscopy (EDS) analysis showed that the intermetallic CuZr2 phase was present even in the low oxygen content alloy, leading to lower fracture strength and ductility loss. For the high oxygen level samples, the presence of the dendritic Zr51Cu28Al21 phase was confirmed, leading to fracture strength impairment. The difference between ductile and brittle samples has been reflected on the fracture surfaces. The higher the plastic strain was, the higher the density of shear bands forming during deformation manifested by a serration flow behaviour on stress-strain curves.
文摘This paper presents methods for determining the basic geometry of end-gear with arc tooth external diameter, width of tooth, end module, number of teeth, pressure angle, tooth, tooth clearance parameters; at the same time gives the tooth bearing strength calculation method, and the formulas to calculate the tooth shear stress, surface stress and bolt fastening force of equivalent stress is established; finally write the software error simulation analysis.
基金supported by the National Basic Research Program of China (Grant No. 2010CB731600)the National Natural Science Foundation of China (Grant Nos. 50731005,50821001 and 51171163)+1 种基金the Doctoral Fund of Ministry of Education of China (Grant No. 20101333110004)the Nature Science Foundation of Hebei (Grant No. E2010001176)
文摘Deformation of the bulk metallic glasses (BMGs) and the creation and propagation of the shear bands are closely interconnected.Shearing force was loaded on Zr 41.2 Ti 13.8 Cu 12.5 Ni 10.0 Be 22.5 (Vit.1) BMGs by cutting during the turning of the BMG rod.The temperature rise of alloy on the shear bands was calculated and the result showed that it could reach the temperature of the super-cooled liquid zone or exceed the melting point.The temperature rise caused viscous fluid flow and brought about the deformation of BMGs.This suggested that the deformation of BMGs was derived,at least to some extent,from the adiabatic shear temperature rise.
