The microstructures and mechanical properties of Ti–47 at%Ni–3 at%Fe shape memory alloy wire under the condition of severe cold-drawing at room temperature and different postdeformation annealing processes were inte...The microstructures and mechanical properties of Ti–47 at%Ni–3 at%Fe shape memory alloy wire under the condition of severe cold-drawing at room temperature and different postdeformation annealing processes were intensively investigated using transmission electron microscope(TEM),X-ray diffraction(XRD),Vickers microhardness tester and electron tensile tester.It is indicated that the structure of the alloy evolves into a predominant amorphous structure with a trace of nanocrystalline B2 phase after the cold-drawing of 76%areal reduction.Postdeformation annealing process exerted significant influence on the microstructure and mechanical properties.Crystallization occurs when the cold-drawn wire was annealed at 300℃ for 30 min.The ultimate tensile strength and ductility as well as the superelasticity of the wire are improved significantly by cold-drawing plus postdeformation annealing.展开更多
In high speed wire drawing, the temperature rise is produced by the generation heat from plastic deformation of metal material and friction between wire and tool, which greatly influences the lubrication situation and...In high speed wire drawing, the temperature rise is produced by the generation heat from plastic deformation of metal material and friction between wire and tool, which greatly influences the lubrication situation and mechanical properties. During high drawing, the phenomenon that wire is embrittled and die is stuck can be formed by the notable temperature rise. In this paper, based on theory of plastic deformation work , considering friction heat generation and variable physical coefficients, the mathematical model of temperature rise of high speed drawing is established and the computer program to analogy the whole process of drawing is compiled. Also the process of wire drawing on a few of alloys are calculated theoretically. Compared the calculation value with measurement, the result shows that the theoretical value coincides with experimental data.展开更多
Castex(continuous cast and extrusion)is a latest metallurgical technology Making of AS wire(aluminum clad steel wire) by Castex is an advanced bonding technology of bimetal In order to study the deformation chara...Castex(continuous cast and extrusion)is a latest metallurgical technology Making of AS wire(aluminum clad steel wire) by Castex is an advanced bonding technology of bimetal In order to study the deformation character of AS wire the numerical simulation is performed with FE method From the simulation result the following conclusions are obtained:① The simulation is carried out sequentially in three zones:initial extrusion,cavity filling and bonding ② In the first zone the shearing deformation governs the whole zone,while in that of cavity filling, the deformation mainly concentrates on transition arc of the concave mould In addition, in the last zone, the dominant deformation lies at the boundary of concave mould, surface of steel wire and entry of sizing band Due to the movement of steel wire, the direction of shear stress on its surface is opposite to that on the boundary of concave die展开更多
Studies have confirmed that iron induces epilepsy onset, and iron ion-induced epilepsy in anima models closely resembles the clinical situation. Models of post-traumatic epilepsy （PTE） were established by intracorti...Studies have confirmed that iron induces epilepsy onset, and iron ion-induced epilepsy in anima models closely resembles the clinical situation. Models of post-traumatic epilepsy （PTE） were established by intracortical injection of FeCl2 using stereotactic techniques. Electron microscopy revealed neuronal degeneration, with shrinkage of the neuronal soma, hyperplasia of rough endoplasmic reticulum, ribosomal detachment from the endoplasmic reticulum, and vacuolar degeneration of glial cells in the right frontal lobe of FeCl2-induced PTE rats. With prolonged time injuries became more severe and neuronal apoptosis was observed. Synapses in the hippocampal neuropil significantly increased （primarily type I/excitatory synapses） at day 14 following injury. Type II synapses （inhibitory synapse） were observed in the rat hippocampus at day 30. Cortical neuronal degeneration, apoptosis, glial cell proliferation, and ultrastructural hippocampal changes, in particular changes in type of neuronal synapse, play an important role in PTE onset.展开更多
基金supported by the National Natural Science Foundation of China (No. 50921003)Industry, Education and Research Projects of the China Aviation Industrial (No.cxy2012BH04)
文摘The microstructures and mechanical properties of Ti–47 at%Ni–3 at%Fe shape memory alloy wire under the condition of severe cold-drawing at room temperature and different postdeformation annealing processes were intensively investigated using transmission electron microscope(TEM),X-ray diffraction(XRD),Vickers microhardness tester and electron tensile tester.It is indicated that the structure of the alloy evolves into a predominant amorphous structure with a trace of nanocrystalline B2 phase after the cold-drawing of 76%areal reduction.Postdeformation annealing process exerted significant influence on the microstructure and mechanical properties.Crystallization occurs when the cold-drawn wire was annealed at 300℃ for 30 min.The ultimate tensile strength and ductility as well as the superelasticity of the wire are improved significantly by cold-drawing plus postdeformation annealing.
文摘In high speed wire drawing, the temperature rise is produced by the generation heat from plastic deformation of metal material and friction between wire and tool, which greatly influences the lubrication situation and mechanical properties. During high drawing, the phenomenon that wire is embrittled and die is stuck can be formed by the notable temperature rise. In this paper, based on theory of plastic deformation work , considering friction heat generation and variable physical coefficients, the mathematical model of temperature rise of high speed drawing is established and the computer program to analogy the whole process of drawing is compiled. Also the process of wire drawing on a few of alloys are calculated theoretically. Compared the calculation value with measurement, the result shows that the theoretical value coincides with experimental data.
文摘Castex(continuous cast and extrusion)is a latest metallurgical technology Making of AS wire(aluminum clad steel wire) by Castex is an advanced bonding technology of bimetal In order to study the deformation character of AS wire the numerical simulation is performed with FE method From the simulation result the following conclusions are obtained:① The simulation is carried out sequentially in three zones:initial extrusion,cavity filling and bonding ② In the first zone the shearing deformation governs the whole zone,while in that of cavity filling, the deformation mainly concentrates on transition arc of the concave mould In addition, in the last zone, the dominant deformation lies at the boundary of concave mould, surface of steel wire and entry of sizing band Due to the movement of steel wire, the direction of shear stress on its surface is opposite to that on the boundary of concave die
基金the Science and Technology Project of Fujian Province of China,No.2007F5045the New Century Talent Support Project of Higher Learning School of Fujian Province,No.NCETFJ-0702
文摘Studies have confirmed that iron induces epilepsy onset, and iron ion-induced epilepsy in anima models closely resembles the clinical situation. Models of post-traumatic epilepsy （PTE） were established by intracortical injection of FeCl2 using stereotactic techniques. Electron microscopy revealed neuronal degeneration, with shrinkage of the neuronal soma, hyperplasia of rough endoplasmic reticulum, ribosomal detachment from the endoplasmic reticulum, and vacuolar degeneration of glial cells in the right frontal lobe of FeCl2-induced PTE rats. With prolonged time injuries became more severe and neuronal apoptosis was observed. Synapses in the hippocampal neuropil significantly increased （primarily type I/excitatory synapses） at day 14 following injury. Type II synapses （inhibitory synapse） were observed in the rat hippocampus at day 30. Cortical neuronal degeneration, apoptosis, glial cell proliferation, and ultrastructural hippocampal changes, in particular changes in type of neuronal synapse, play an important role in PTE onset.
