Xuefeng Liu

• Principal Investigator at University of Science and Technology Beijing

Zn–Ni alloy coatings were deposited on rolled copper foil via electro-brush plating with different micro-force. Surface morphologies, microhardness, roughness, and bending performance were characterized. Mechanisms and influences of electro–brush plating micro-force on coatings performances were investigated and revealed. With the increase of elect...

Cu–4.7 wt. % Sn alloy wire with Ø10 mm was prepared by two-phase zone continuous casting technology, and the temperature field, heat and fluid flow were investigated by the numerical simulated method. As the melting temperature, mold temperature, continuous casting speed and cooling water temperature is 1200 °C, 1040 °C, 20 mm/min and 18 °C, respec...

Poly (alpha-olefin) (PAO, commonly used rolling base oil) attached to the surface of copper foil was degradated using photocatalytic microreactor. The chemical state, free radical and functional groups during the degradation process were detected by X-ray photoelectron spectroscopy (XPS), electron spin resonance spectroscopy(ESR) and Fourier transf...

The technologies of brush plating and dealloying were used to treat the surface of rolled copper foil. Zn–Ni and Sn–Zn alloy coatings were prepared. The laws of plating solutions composition and technological parameters on coatings quality were investigated. The results show that with the decreasing of main elements mass ratio or increasing of brus...

Cu-4.7%Sn (mass fraction) alloy plate was prepared by the self-developed two-phase zone continuous casting (TZCC) process. The relationship between process parameters of TZCC and surface quality of the alloy plate was investigated. The microstructure and mechanical properties of the TZCC alloy plate were analyzed. The results show that Cu-4.7%Sn al...

The surface morphology of double-rolled copper foil was characterized.•The morphology evolution of laminated surface in the deforming zone was observered.•The formation mechanism of matt surface was revealed.•The advantage of treating matt surface as adhesive surface was analyzed.

Brush plating technology was employed to directly achieve double coatings of Zn–Ni alloy and Sn–Zn alloy on the surface of rolled copper foil. Dealloying technology was applied to implement porous surface. Surface morphology, roughness, chemical composition, corrosion resistance and interfacial bonding strength of copper foil and double coatings we...

Developing ultra-thin copper foils with different surface roughness and microstructure has important significance for improving the service performance and reducing the production cost of high-end circuit boards. In this paper, pure copper strips with initial cube texture were subjected to a double rolling process (deformation amount ranges from 50...

In order to study the influence of MgO-C refractory on steel cleanliness and inclusions during steelmaking process, and to understand the reaction mechanism deeply, laboratory deoxidation and equilibrium experiments were respectively performed in MgO crucibles at 1873K. In the former experiment, after Al addition, steel samples were taken at differ...

Copper foils with gradient structure in thickness direction and different roughnesses on two surfaces were fabricated by double rolling. The two surface morphologies of double-rolled copper foils are quite different, and the surface roughness values are 61 and 1095 nm, respectively. The roughness value of matt surface can meet the requirement for b...

The effects of room-temperature deformation on mechanical properties, the microstructure and texture evolution of continuous columnar-grained BFe10-1-1 cupronickel alloy tubes during room-temperature rolling and drawing were investigated. The results showed that continuous columnar grains were gradually thinned down into fiber microstructure, and t...

Dieless drawing experiments of continuous columnar-grained Cu-14.0%Al-3.8%Ni (mass fraction) alloy wires were carried out at drawing speeds of 0.8-1.1 mm/s and deformation temperatures of 650-900°C, when the feeding speed and distance between the heating and the cooling sources kept invariant at 0.50 mm/s and 15 mm, respectively. Effects of dieless...

Efficient secondary refining process is necessary for massive and stable production of low carbon aluminum-killed (LCAK) steels. Plant trials were performed to investigate the cleanliness of steels. Characteristics of composition, cleanliness, and inclusions of LCAK steel during different secondary refining processes, including LF, CAS, RH-LIT, and...

The Ohno continuous casting process was used to produce CuNi10Fe1Mn alloy rods with unidirectional morphologies. The results of tensile tests showed that the present alloy exhibited an elongation of 51%, which cannot be obtained by conventional processes such as the sand casting or continuous casting. Scanning electron microscopy of the fracture su...

A new theory of two-phase zone continuous casting (TZCC) has been established in order to improve mechanical properties, corrosion resistance and conductivity properties of metals with wide solid–liquid two-phase zone. A Cu–Sn alloy with continuous columnar grains-covered non-columnar small grains of same phase microstructure containing many self-c...

Residual stress of a BFe10-1-1 alloy tube with continuous columnar grains was measured after dieless drawing by X-ray method. The microstructure of the tube was observed by means of TEM. The dieless drawing of the tubes was performed in the temperature of 850°C at the drawing speed of 0.7 mm·s-1 and the feed speed of 0.5 mm·s-1. The mechanism of re...

A plant trial of the productions of LCAK steel was performed, and characteristics of inclusions during LF refining and calcium treatment were investigated. Besides, thermodynamic diagram among magnesium, aluminum, and oxygen as well as calcium, magnesium, aluminum, and oxygen in the steel melt were studied to understand the fundamentals of inclusio...

The dieless drawing forming of BFe10-1-1 alloy tubes with continuous columnar grains was performed in a temperature range of 750-900°C at a drawing speed of 0.6-0.9 mm·s-1. The microstructural evolution and mechanism of the tubes after the deformation was studied by optical microscopy, transmission electron microscopy, and X-ray diffraction analysi...

Ultra-low carbon steel, in which titanium is used to fix the interstitial atoms such as C and N, is well used for automobile. During the RH refining process, the evolution of oxide inclusions was analyzed using ASPEX and acid extraction. It was found that after Ti addition a large amount of Al-Ti-O inclusions generated, and the Ti content in the ox...

The billet was prepared by putting the aluminum bar into the silver tube, and the silver clad aluminum wire was fabricated through cold hydrostatic extrusion and subsequent drawing. The effects of annealing parameters on the interface and properties of the wires were investigated. The results showed that when the annealing temperature was below 150...

Based on orthogonal design, black ceramic coating was obtained on AZ91D magnesium alloy with addition of carbon black pigment in electrolyte by micro-arc oxidation (MAO). The blackness, thickness, phase, morphology and composition of the coating were analyzed by visual detection, eddy current thickness meter, XRD, digital cameras and EDS. The reaso...

In this paper, a novel safe and high-efficient fabrication processing named in-situ reaction and unidirectional solidification method was presented for lotus-type porous metals. The fabrication process of lotus-type porous magnesium by the in-situ reaction method had been investigated, and the rule of effect of processing parameters on pore structu...

In this paper, the tensile mechanical properties and fatigue strengths of single-crystal and columnar-grained polycrystalline Cu-12wt.%Al alloy rods prepared by Ohno continuous casting (OCC) technology were investigated and compared with those properties of polycrystalline Cu-12wt.%Al alloy prepared by conventional casting. The results of tensile t...

The room temperature tensile and compressive mechanical behaviors of a β1′ martensitic Cu-12 wt.% Al alloy with < 001>β1 or < 011>β1 orientation fabricated by Ohno continuous casting were investigated. An orientation-dependent tension–compression asymmetry was observed in the specimens. The various stress-induced martensite–martensite transformatio...

A deformation measurement method of interframe displacement was proposed in this paper. By online monitoring the shape dimensions of both the deformation zone and its adjacent zone by machine vision, the initial and terminative positions of deformation were dynamically identified during dieless drawing, and the global monitoring and online closed-l...

Copper cladding aluminum (CCA) rods with a diameter of 30 mm and a sheath thickness of 3 mm were fabricated by horizontal core-filling continuous casting (HCFC) technology. The microstructure and morphology, distribution of chemical components, and phase composition of the interface between Cu and Al were characterized by scanning electron microsco...

The corrosion resistance of BFe10-1-1 alloy with continuous columnar-grained microstructure in a 3.5% NaCl solution was investigated by means of polarization tests and electrochemical impedance spectroscopy (EIS), and compared with that of BFe10-1-1 alloy with conventional polycrystalline microstructure fabricated by conventional casting. Polarizat...

Effects of melt temperature and casting speed on microstructure and mechanical properties of Cu-14%Al-3.8%Ni (mass fraction) alloy wires fabricated by continuous unidirectional solidification technology were investigated. It was found that the average size of columnar grain in the alloy decreased and grain boundary turned clear and straight with in...

Since processing parameters have always been assumed to be stable in the current finite element numerical simulation of dieless drawing process, the simulation results for the product dimension tend to stabilize gradually. In fact, the dimension fluctuation exists in the forming process all the while. A mathematical model of Gauss distribution for...

Tin bronze wires were produced by dieless drawing. The effects of heating power, the distance between cooler and heater as well as feeding speed on the diameter, the temperature field, and the deformation region profile of the wires were investigated. The results indicated that each processing parameter exhibited both lower and upper limits of stab...

The thickness distribution of oxidation film on the surface of AISI304 stainless steel tapered pipe, its influence factors, and the effect of metal matrix deformation on oxidation behavior during dieless drawing were studied in this paper. The results showed that oxidation rate was affected strongly by induction heating temperature and deformation...

Cu-12%Al alloy wires with a diameter of 6 mm were prepared by vacuum melting and argon shield vertical continuous unidirectional solidification process. The effects of melt temperature, crystallizer length and drawing velocity on the surface quality, microstructure and mechanical properties of the alloy wires were investigated. The results show tha...

Cu-12%Al (mass fraction) alloy single crystal wires were prepared by the continuous unidirectional solidification. Various martensite structures were obtained by changing the melt temperature. The effects of martensite orientation and morphologies on the mechanical properties of the alloy wires were investigated. The results show that the Cu-12%Al...

Based on the compression experimental data of BFe10-1-1 alloy with continuous unidirectionally solidified columnar grains, a prediction model for the relation of true stress to temperature, strain rate and true strain was developed using an adaptive network based fuzzy inference system (ANFIS) . The temperature at which the alloy was compressed was...

In the future urban public intelligent building will be the developmental direction, building automation as an important component of intelligent building is an important means to reduce building energy consumption. At present operating characteristic's individual differences of air-conditioning system is often ignored in building automation system...

Dynamic recrystallization behavior of a Cu-based alloy BFe10-1-1 with continuous columnar grains was investigated by hot compression test. Specimen was compressed in the temperature range of 750 to 900°C and the strain rate range of 0.01 to 10 s-1. The results indicate that the dynamic recrystallization temperature of the tested alloy is about 850°...

In dieless drawing process, the product shape and the dimensional accuracy depend on process parameters completely. Adopting theory and experimental method, the effect of process parameters on dimensional stability, bus straightness and limit section reduction ratio were analyzed. The results show that the limit section reduction ratio can be incre...

In dieless drawing process of 304 stainless steel cone-shape pipe, the thickness of oxide film and factors influencing the formation of oxide film were analyzed, and the effects of pickling temperature and pickling speed on the chemical removal process of the oxide film were studied. The results show that the oxide film thickness is gradually incre...

Copper cladding aluminum (CCA) rods with a diameter of 30mm and a sheath thickness of 3mm were fabricated by horizontal core-filling continuous casting (HCFC) technology. The effects of key processing parameters, such as the length of the mandrel tube of composite mold, aluminum casting temperature, flux of the secondary cooling water, and mean wit...

Effect of γ2 phase evolution on mechanical properties of Cu-14%Al-3.8%Ni (mass fraction) alloy wires fabricated by continuous unidirectional solidification technology was investigated before and after heat treated at 700-780°C. Mechanism for the improvement of mechanical properties of the alloy was analyzed. It was found that the alloy retained con...

By moving out of induction heater for crystallizer, the solid-liquid interface was controlled at the exit of crystallizer during Ohno continuous casting(OCC). Based on the temperature field equations of melt region, liquid/solid interface, air cooling region and water cooling region, the relationship was deduced among the maximum steady-state drawi...

The back-propagation neural (BPN) network was proposed to model the relationship between the parameters of the dieless drawing process and the microstructures of the QSi3-1 silicon bronze alloy. Combined with image processing techniques, grain sizes and grain-boundary morphologies were respectively determined by the quantitative metallographic meth...

BFe10-1-1 cupronickel alloy tubes were fabricated by the vertical downward continuous unidirectional solidification with vacuum melting and argon-shield. The effects of processing parameters on the surface quality of alloy tubes have been investigated, and the microstructure and mechanical properties of cupronickel alloy tubes were characterized. T...

An analytical model of the induction heating specific power distribution function of dieless drawing was developed. A new method of graphic fitting combined with genetic inverse algorithm was put forward to obtain the undetermined functions in the specific power distribution function. The dieless drawing of NiTi alloy had been used to establish the...

In order to improve the surface quality of the dieless drawn products, to optimize the process parameters and to predict the thickness of oxide films, the deformation temperature, deformation degree and other factors on the impact of metal oxidation were analyzed. In accordance with the dieless drawing process of cone-shape pipes, the metal oxidati...

A speed control model for continuous dieless drawing process of tapered pipes is established on the basis of the volume incompressibility principle of metal. The effects of drawing speed and other deformation process parameters on the volume of the deformation zone and the size of the tapered pipe were analyzed and verified by experiment. The resul...

The process and action mechanism of surface treatment of p-phenylene-2, 6-benzobisoxazole (PBO) fibers had been investigated under the conditions of ultrasonic wave and the mixed solution of polyphosphoric acid (PPA) and ethanol. The surface morphology, tensile property and interfacial adhesion between fiber and resins were characterized by scannin...

The microstructure and mechanical properties of Cu-12wt%Al alloy wires which are composed of continuous columnar crystals after dieless drawing forming at drawing speed of 1.0–1.4 mm/s and deformation temperature of 600–900°C were analyzed, and deformation behavior of the alloy during dieless drawing forming was experimentally investigated. The res...

Taking glass-coated FeCoSiB microwires as the research object, the influences of the concentration of hydrofluoric acid solution (HF) and reaction temperature on the removal speed of glass coatings were investigated, and the protection effects of inhibitors on FeCoSiB cores were analyzed. The results show that with the mass fraction of HF increased...

On the basis of the compression experiment data obtained from Gleeble-1500 thermal simulator, the predicted model of the whole process of high temperature deformation for the relation between true stress and true strain, strain rate and temperature for Cu-12%(mass fraction) Al alloy was developed with BP Neural Network (BPNN) method. The results sh...

Hot compression deformation of AZ91 magnesium alloy has been performed on Gleeble-1500 under conditions of strain rates of 0.001-1 s-1 and deformation temperatures of 250- 400°C, and the flow stresses in different deformation conditions are investigated. The results show that the flow stress is significantly affected by both deformation temperature...

Lotus-type porous copper bars of 45 mm in diameter and 120 mm in length were fabricated by unidirectional solidification at hydrogen pressure of 0.2 MPa and molten temperature of 1200 °C. The compressive deformation process and its effect factors were investigated. The deformation mechanism of lotus-type porous copper was also analyzed and discusse...

Cu-14.3%Al-4%Ni (mass fraction) alloy pipes were prepared by vacuum melting and argon-shield vertical continuous unidirectional solidification process. The effects of process parameters on the solidification forming were investigated and the microstructure and properties of the pipes were analyzed. The results show that Cu-14.3%Al-4%Ni alloy pipes...

The appropriate annealing process for cold-drawing copper cladding aluminum wire was studied. The variations of mechanical properties, microstructure of copper sheaths and diffusion thickness of copper cladding aluminum wires with annealing process were investigated. The results show that the proper annealing process for copper cladding aluminum wi...

The effects of annealing temperature on the microstructure and mechanical property of copper cladding aluminum wires fabricated by cold hydrostatic extrusion were investigated, and its influence mechanism was discussed on the basis of different interface fracture modes. The experimental results showed that the appropriate annealing temperature is 3...

Using Matlab software, the prediction model of wire diameter in dieless drawing process is established based on BP neural network method. The experimental results show that the prediction model is effective and reliable. The average relative error between the predictions and the experimental results is 0.52%, and the maximal relative error is 2.42%...

Optimization of process parameters is the precondition of the precise controlling of the product quality in materials process. In this work, choosing the fluctuation of the wire diameter during the initial stage of the dieless drawing process as the evaluating criterion, the process parameters were optimized by artificial intelligence which combine...

On the basis of the compression experiment data obtained from Gleeble-1500 Thermal Simulator, the predicting models for the relation between true stress and true strain, strain rate and temperature for Ti-50.5 Ni alloy have been developed with BP(back propagation) Artificial Neural Network method. The results show that, it is feasible to establish...

The copper cladding aluminum ultra-fine flat wires are fabricated by cold hydrostatic extrusion combined subsequent cold-drawing, cold rolling and heat treatment, and the effect of rolling process on deforming characteristic, mechanical properties and surface quality of the flat wires, and the effect of heat treatment process on mechanical properti...

Silver clad aluminum wires (diameter less than 100μm) were fabricated through cold hydrostatic extrusion followed by drawing process. The results show that the ratio of hardness of silver tube to aluminum rod and modular angle are the critical factors that contribute to the success of the hydrostatic extrusion process. When the ratio of hardness of...

The hot deformation behavior of Ni-Ti alloy was studied by compressive deformation tests in the strain rate range of 10-3-101 s-1 and temperature rage of 700-900°C, and the associated structural changes were investigated by metallography and TEM. By using regression analysis methods based on measured data, the material parameters in the Arrhenius-t...

Pure copper plates were prepared by vacuum melting and argon-shield vertical continuous unidirectional solidification process. The effects of process parameters on the solidification forming were investigated, and microstructure and properties of the fabricated plates were analyzed. The results showed that pure copper plates of 25 mm in width and 5...

Microstructures and mechanical properties of AZ91 magnesium alloy after homogenization, hot extrusion and succedent aging are investigated. The results show that dynamic recrystallization occurred during extrusion at elevated temperatures of 320 and 380 V. Compared to the as-cast alloy, the microstructures of the extruded AZ91 alloy are refined, an...

The glass-coated pure copper microwires were prepared by melt spinning method, and a study on removing the glass coat was carried out by experiment. The corrosion behavior of the microwires in aqueous HF solution and melting NaOH were investigated respectively, and the anti-corrosion property of glass-coated pure copper microwires in strongly acid...

Cu-12%Al alloy (mass fraction) wires were prepared by vacuum melting and argon-shield vertical continuous unidirectional solidification process. Effects of process parameters on the solidification forming were investigated, and the microstructure and properties of the wires were analyzed. The results showed that Cu-12%Al wires with 6 mm in diameter...

In order to improve the mechanical properties and the workability of as-cast AZ91 magnesium alloy, homogenizing annealing treatment was carried out, the annealing temperatures ranged from 350 to 450°C and the holding times from 5 to 24 h. After homogenizing treatment, the fine Mg17Al12 phase distributed in the α-Mg matrix, and dendritic segregation...

The temperature distribution in a crystallizer has important influence on the position and shape of solid-liquid interface during continuous unidirectional solidification. Based on the established three-dimensional physical model, simplified terms, specified material parameters in thermal and physical properties, boundary conditions, and the calcul...

The finite element model of temperature field of micro melting bath in melt spinning was developed based on the fabrication of glass-coated pure copper. By using the method of magnetic-thermal coupling, the influence rules of some process parameters, including the mass of raw material, heating current, the number of turns and cone angle of inductio...

Glass-coated pure copper microwire is prepared by the melting spinning method. The microstructure of the microwire is observed while the model of solidification process of pure copper core under different cooling conditions is presented, and the size and the defects are characterized. The results show that: the microstructure of the micro wires coo...

Lotus-type porous pure copper bars with diameter of 45 mm and height of 125 mm were fabricated by unidirectional solidification at hydrogen pressure of 0.2 MPa and molten temperature of 1200°C. Density, porosity and ratio of open pores of the fabricated samples were measured. Shape and diameter distribution of the pores were characterized, and comp...

By introducing the Zener-Hollomon parameters, which synthesize the influence of deformation temperature and strain rate into damage mechanics, a damage evolution model was developed to simulate the damage evolution of metallic materials during hot deformation. The errors between the prediction damage values and the experimental ones are within 6%.