Zr-Ti binary alloys are prepared using a nonconsumable tungsten electrode under Ti-gettered inert atmosphere(argon).Microstructures are observed mainly asαphase using x-ray diffraction.A tensile test is performed to ...Zr-Ti binary alloys are prepared using a nonconsumable tungsten electrode under Ti-gettered inert atmosphere(argon).Microstructures are observed mainly asαphase using x-ray diffraction.A tensile test is performed to investigate the tensile strength of a series of Zr-Ti binary alloys at room temperature.The findings indicate that increasing Ti concentration results in an initial increase(<50at%of Ti)and then a decrease in tensile strength.The Zr55Ti45(at%)component exhibits the maximum tensile strength of 1216.68 MPa,which is much higher than that of pure Ti(increased by approximately 200%)or pure Zr(increased by approximately 100%).The potential mechanisms for the remarkable tensile strength are solid solution strengthening and grain refinement.展开更多
The Voronoi structural evolution of silicon upon melting is investigated using a molecular dynamics simulation.At temperatures below the melting point,the solid state system is identified to have a four-fold coordinat...The Voronoi structural evolution of silicon upon melting is investigated using a molecular dynamics simulation.At temperatures below the melting point,the solid state system is identified to have a four-fold coordination structure(4,0,0,0).As the temperature increases,the five−fold coordination(2,3,0,0)and six−fold coordination structures(2,2,2,0)and(0,6,0,0)are observed.This is explained in terms of increasing atomic displacement due to thermal motion and the trapping of the moving atoms by others.At temperatures above the melting point,nearly all of the four-fold coordination structures grows into multiple-fold coordination ones.展开更多
A remarkable enhancement in room-temperature compressive deformability is realized by the minor-addition of 1.5 at.%Al in ZrTi-based bulk metallic glass.Two amorphous phases are observed by transmission electron micro...A remarkable enhancement in room-temperature compressive deformability is realized by the minor-addition of 1.5 at.%Al in ZrTi-based bulk metallic glass.Two amorphous phases are observed by transmission electron microscopy in the Al-containing alloys and this explains the improvement of compression deformability.The studies suggest that phase separation might occur in glass forming alloys with a negative enthalpy of mixing.展开更多
Single crystals ofβ–FeSi_(2) have been grown from vapor by employing chemical vapor transport technique and using iodine as transport agent in a closed ampoule.In the experiment,β–FeSi_(2) single crystals with wel...Single crystals ofβ–FeSi_(2) have been grown from vapor by employing chemical vapor transport technique and using iodine as transport agent in a closed ampoule.In the experiment,β–FeSi_(2) single crystals with well-developed faces and edges have been observed on the silicon substrate,but no needlelike ones have been found.The changes in the size and the geometric shape of the growth ampoule and temperature gradient are primary factors which result in the variation on β–FeSi_(2) single crystal morphology.展开更多
Undercooled melt of Ge_(73.7)Ni_(26.3) alloy sample floated on B_(2)O_(3 ) melt was subjected to sputtering-deposition of Ni clusters on cooling to induce solidification.The initial temperature of solidification was 9...Undercooled melt of Ge_(73.7)Ni_(26.3) alloy sample floated on B_(2)O_(3 ) melt was subjected to sputtering-deposition of Ni clusters on cooling to induce solidification.The initial temperature of solidification was 975 K.Its undercoolingΔT was 134 K with respect to the melting temperature of the primary phase Ge.On the cooling curve existed dual recalescences representing the transformation of the primary phase(Ge)and the eutectics(Ge+GeNi)respectively.But for the sample unsputtered,only a single exothermic peak presented on the cooling curve with the initial solidification temperature of 904K and undercooling of 205K.Careful observation of the microstructure proved that the Ge phase primarily formed in the sputtering experiment was now formed together with the formation of the eutectics in the experiment without sputtering.展开更多
The in situ four-point probe resistivity measurement was used as a main method to study the solid/liquid interfacial characteristics in Ag/Sn/Ag trilayers at temperatures ranging from 150 to 305℃.It is found from the...The in situ four-point probe resistivity measurement was used as a main method to study the solid/liquid interfacial characteristics in Ag/Sn/Ag trilayers at temperatures ranging from 150 to 305℃.It is found from the variation of resistivity that three processes take place on annealing:the dissolution of silver atoms,the diffusion of silver atoms,and the formation of Ag3Sn in liquid tin layer.The first one plays the leading role in the variation of resistivity during annealing process.The apparent diffusivity of silver in liquid tin at 305℃ is determined to be 7.3×10^(-17)cm^(2)/s.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2010CB731600 and 2013CB733000the National Natural Science Foundation of China under Grant Nos 51121061,51271161 and 51171163.
文摘Zr-Ti binary alloys are prepared using a nonconsumable tungsten electrode under Ti-gettered inert atmosphere(argon).Microstructures are observed mainly asαphase using x-ray diffraction.A tensile test is performed to investigate the tensile strength of a series of Zr-Ti binary alloys at room temperature.The findings indicate that increasing Ti concentration results in an initial increase(<50at%of Ti)and then a decrease in tensile strength.The Zr55Ti45(at%)component exhibits the maximum tensile strength of 1216.68 MPa,which is much higher than that of pure Ti(increased by approximately 200%)or pure Zr(increased by approximately 100%).The potential mechanisms for the remarkable tensile strength are solid solution strengthening and grain refinement.
基金by the National Natural Science Foundation of China under Grant Nos 50771090,50821001 and 51002130.
文摘The Voronoi structural evolution of silicon upon melting is investigated using a molecular dynamics simulation.At temperatures below the melting point,the solid state system is identified to have a four-fold coordination structure(4,0,0,0).As the temperature increases,the five−fold coordination(2,3,0,0)and six−fold coordination structures(2,2,2,0)and(0,6,0,0)are observed.This is explained in terms of increasing atomic displacement due to thermal motion and the trapping of the moving atoms by others.At temperatures above the melting point,nearly all of the four-fold coordination structures grows into multiple-fold coordination ones.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50731005,50821001 and 50944029the Natural Science Foundation of Hebei Province under Grant No E2010001176.
文摘A remarkable enhancement in room-temperature compressive deformability is realized by the minor-addition of 1.5 at.%Al in ZrTi-based bulk metallic glass.Two amorphous phases are observed by transmission electron microscopy in the Al-containing alloys and this explains the improvement of compression deformability.The studies suggest that phase separation might occur in glass forming alloys with a negative enthalpy of mixing.
基金Supported by the National Natural Science Foundation of China under Grant No.59889102.
文摘Single crystals ofβ–FeSi_(2) have been grown from vapor by employing chemical vapor transport technique and using iodine as transport agent in a closed ampoule.In the experiment,β–FeSi_(2) single crystals with well-developed faces and edges have been observed on the silicon substrate,but no needlelike ones have been found.The changes in the size and the geometric shape of the growth ampoule and temperature gradient are primary factors which result in the variation on β–FeSi_(2) single crystal morphology.
文摘Undercooled melt of Ge_(73.7)Ni_(26.3) alloy sample floated on B_(2)O_(3 ) melt was subjected to sputtering-deposition of Ni clusters on cooling to induce solidification.The initial temperature of solidification was 975 K.Its undercoolingΔT was 134 K with respect to the melting temperature of the primary phase Ge.On the cooling curve existed dual recalescences representing the transformation of the primary phase(Ge)and the eutectics(Ge+GeNi)respectively.But for the sample unsputtered,only a single exothermic peak presented on the cooling curve with the initial solidification temperature of 904K and undercooling of 205K.Careful observation of the microstructure proved that the Ge phase primarily formed in the sputtering experiment was now formed together with the formation of the eutectics in the experiment without sputtering.
文摘The in situ four-point probe resistivity measurement was used as a main method to study the solid/liquid interfacial characteristics in Ag/Sn/Ag trilayers at temperatures ranging from 150 to 305℃.It is found from the variation of resistivity that three processes take place on annealing:the dissolution of silver atoms,the diffusion of silver atoms,and the formation of Ag3Sn in liquid tin layer.The first one plays the leading role in the variation of resistivity during annealing process.The apparent diffusivity of silver in liquid tin at 305℃ is determined to be 7.3×10^(-17)cm^(2)/s.
