Electroless Cu plating was used for flake G powder and CNTs, Cu-G-CNTs （copper/graphite/carbon nanotubes） composites were manufactured by means of powder metallurgical method. The influences of CNTs on the mechanica...Electroless Cu plating was used for flake G powder and CNTs, Cu-G-CNTs （copper/graphite/carbon nanotubes） composites were manufactured by means of powder metallurgical method. The influences of CNTs on the mechanical properties, conductivity properties, friction, and wear performance of the composite were examined. The results indicate that adding a small amount of CNTs can improve comprehensive property of the composites, especially mechanical property. However, excessive CNT, which is easily winding reunion and grain boundary seg- regation, results in performances degradation.展开更多
The Zr62.55Cu17.55Ni9.9Al10 bulk metallic glass （BMG） was prepared by using copper-mold suction-casting. X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal s...The Zr62.55Cu17.55Ni9.9Al10 bulk metallic glass （BMG） was prepared by using copper-mold suction-casting. X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal stability. Uniaxial compression and Rockwell indenta- tion tests were adopted to study the plastic deformation behavior at room temperature. The results show that the glass transition temperature and the onset temperature of exothermic reaction of the BMG are 651.5 and 748 K, respectively. During the compression test, the BMGs undergo an engineering strain of about 2.5%, i.e., true strain of 2.8%, and then fracture. The BMGs deform via the formation and propagation of shear bands. Under indentation loading, the BMGs deform through the formation of radiation-like and circular shear bands. The circular shear bands form earlier than the radiation-like ones, The formation mechanism of shear bands in the BMGs was analyzed and discussed.展开更多
The aim of this study was to develop conductive adhesive using silver nanowires prepared via solvothermal method as conductive fillers and epoxymodified organosilicone resin as matrix resin. Effect of the addition of ...The aim of this study was to develop conductive adhesive using silver nanowires prepared via solvothermal method as conductive fillers and epoxymodified organosilicone resin as matrix resin. Effect of the addition of silver nanowires/flakes on the conductive adhesive＇s electrical and mechanical properties was investigated. Compared with conventional conductive adhesive with silver flakes fillers, the percolation threshold of conductive adhesive with silver nanowires fillers is 10 % lower approximately. However, further rise of the content of silver nanowires has no obvious influence on improvement of the electrical conductivity of conductive adhesive. Both conductive and mechanical properties of conductive adhesive can be compatible by adding silver nanowires, which traditional silver conductive adhesives cannot reach.展开更多
Compositional dependences on microstructures and martensitic transformation behaviors in（Cu_（0.5）Zr_（0.5））_（100-x）Zn_x（x=1.5,2.5,4.5,7.0,10.0,and 14.0at.%）alloys were investigated.It was found that CuZr mart...Compositional dependences on microstructures and martensitic transformation behaviors in（Cu_（0.5）Zr_（0.5））_（100-x）Zn_x（x=1.5,2.5,4.5,7.0,10.0,and 14.0at.%）alloys were investigated.It was found that CuZr martensites were present in the present alloys.With increasing Zn content,the volume fractions of CuZr martensitic crystals and B2 CuZr phase gradually decrease and increase,respectively.With the addition of high Zn contents（i.e.,7.0,10.0,and 14.0at.%）,the matrix proves to be eutectic.Thermal analysis results show that the initial martensitic transformation temperature（M_s）decreases from（412±5）K to（329±5）K as the Zn content increases from 1.5at.% to14.0at.%.The values of Msof Cu-Zr-Zn shape memory alloys are inversely proportional to the number and concentrations of valence electrons（i.e.,e_v/a and c_v）,respectively,implying that the martensitic transformation in CuZrZn alloys could be of electronic nature.展开更多
基金financially supported by the National Nature Science Foundation of China (No. 51003060)the Distinguished Young Talents in Higher Education of Guangdong China (No. 2012LYM_0118)the Shenzhen Innovation and Technology Commission under the Strategic Emerging Industries Development Project (No. ZDSY20120612094418467)
文摘Electroless Cu plating was used for flake G powder and CNTs, Cu-G-CNTs （copper/graphite/carbon nanotubes） composites were manufactured by means of powder metallurgical method. The influences of CNTs on the mechanical properties, conductivity properties, friction, and wear performance of the composite were examined. The results indicate that adding a small amount of CNTs can improve comprehensive property of the composites, especially mechanical property. However, excessive CNT, which is easily winding reunion and grain boundary seg- regation, results in performances degradation.
基金supported by the National Natural Science Foundation of China (Nos50971046,50771037,and 50371020)the Doctoral Fund of the Ministry of Education of China (No200805620004)
文摘The Zr62.55Cu17.55Ni9.9Al10 bulk metallic glass （BMG） was prepared by using copper-mold suction-casting. X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal stability. Uniaxial compression and Rockwell indenta- tion tests were adopted to study the plastic deformation behavior at room temperature. The results show that the glass transition temperature and the onset temperature of exothermic reaction of the BMG are 651.5 and 748 K, respectively. During the compression test, the BMGs undergo an engineering strain of about 2.5%, i.e., true strain of 2.8%, and then fracture. The BMGs deform via the formation and propagation of shear bands. Under indentation loading, the BMGs deform through the formation of radiation-like and circular shear bands. The circular shear bands form earlier than the radiation-like ones, The formation mechanism of shear bands in the BMGs was analyzed and discussed.
基金financially supported by the Shenzhen Innovation and Technology Commission under the Strategic Emerging Industries Development Project(No.ZDSY2012061209 4418467)
文摘The aim of this study was to develop conductive adhesive using silver nanowires prepared via solvothermal method as conductive fillers and epoxymodified organosilicone resin as matrix resin. Effect of the addition of silver nanowires/flakes on the conductive adhesive＇s electrical and mechanical properties was investigated. Compared with conventional conductive adhesive with silver flakes fillers, the percolation threshold of conductive adhesive with silver nanowires fillers is 10 % lower approximately. However, further rise of the content of silver nanowires has no obvious influence on improvement of the electrical conductivity of conductive adhesive. Both conductive and mechanical properties of conductive adhesive can be compatible by adding silver nanowires, which traditional silver conductive adhesives cannot reach.
基金Item Sponsored by National Natural Science Foundation of China(51501103)Fundamental Research Funds for the Central Universities on Northwestern Polytechnical University of China(GEKY1008)
文摘Compositional dependences on microstructures and martensitic transformation behaviors in（Cu_（0.5）Zr_（0.5））_（100-x）Zn_x（x=1.5,2.5,4.5,7.0,10.0,and 14.0at.%）alloys were investigated.It was found that CuZr martensites were present in the present alloys.With increasing Zn content,the volume fractions of CuZr martensitic crystals and B2 CuZr phase gradually decrease and increase,respectively.With the addition of high Zn contents（i.e.,7.0,10.0,and 14.0at.%）,the matrix proves to be eutectic.Thermal analysis results show that the initial martensitic transformation temperature（M_s）decreases from（412±5）K to（329±5）K as the Zn content increases from 1.5at.% to14.0at.%.The values of Msof Cu-Zr-Zn shape memory alloys are inversely proportional to the number and concentrations of valence electrons（i.e.,e_v/a and c_v）,respectively,implying that the martensitic transformation in CuZrZn alloys could be of electronic nature.
