Multiscale simulation of nanometric cutting of single crystal copper——effect of different cutting speeds

A multiscale simulation has been performed to determine the effect of the cutting speed on the deformation mechanism and cutting forces in nanometric cutting of single crystal copper. The multiscale simulation model, which links the finite element method and the molecular dynamics method, captures the atomistic mechanisms during nanometric cutting from the free surface without the computational cost of full atomistic simulations. Simulation results show the material deformation mechanism of single crystal copper greatly changes when the cutting speed exceeds the material static propagation speed of plastic wave. At such a high cutting speed, the average magnitudes of tangential and normal forces increase rapidly. In addition, the variation of strain energy of work material atoms in different cutting speeds is investigated.

MULTIAXIAL BEHAVIOR OF NANOPOROUS SINGLE CRYSTAL COPPER:A MOLECULAR DYNAMICS STUDY

The stress-strain behavior and copper are studied by the molecular dynamics incipient yield surface of nanoporous single crystal （MD） method. The problem is modeled by a periodic unit cell subject to multi-axial loading. The loading induced defect evolution is explored. The incipient yield surfaces are found to be tension-compression asymmetric. For a given void volume fraction, apparent size effects in the yield surface are predicted： the smaller behaves stronger. The evolution pattern of defects （i.e., dislocation and stacking faults） is insensitive to the model size and void volume fraction. However, it is loading path dependent. Squared prismatic dislocation loops dominate the incipient yielding under hydrostatic tension while stacking-faults are the primary defects for hydrostatic compression and uniaxial tension/compression.

Relationships between the surface quality of a single crystal copper ingot and the process parameters of a heated mould continuous casting method

The relationships between the surface quality of a single crystal copper ingot and the process parameters of heated mould continuous casting method were studied experimentally using our own design of horizontal heated mould continuous casting apparatus, and the mechanism by which process parameters affect the surface quality of a single crystal copper ingot is analyzed in the present paper. The results show that the process parameters affect the surface quality of a pure copper ingot by affecting the position of the liquid-solid interface in the mould. The position of the liquid-solid interface in the mould must be controlled carefully within an appropriate range, which is determined through a series of experiments, in order to gain a single crystal copper ingot with good surface quality.

Process Parameters of Manufacturing Single Crystal Copper by Heated Mold Continuous Casting

The effect of process parameters on the surface quality of single crystal copper ingot was studied through experiment with a self-designed horizontal heated mould continuous casting apparatus,and the mechanism was analyzed.The results show that the process parameters affect the surface quality of pure copper ingot by affecting the position of the liquid-solid interface in the mould.The position of the liquid-solid interface in the mould must be controlled carefully in an appropriate range determined through experiments in order to gain a single crystal copper ingot with a high surface quality.

Molecular Dynamics Study on Wavefront Structure of Single Crystal Copper under Femtosecond Laser Loading

We used computer simulation with the advantage of easily designing the material structure to design single crystal copper samples,studied the mechanical behaviors of this material under different shock compression conditions,and comparatively analyzed the reasons for the formation of different mechanical behaviors.An important macro performance of metal mechanical behaviors under shock compression is the shock wave front.In fact,the structure and the evolution of the shock wave front during the plastic phase are determined by its microscopic process,i.e.,the development process of shear flow and energy dissipation in the plastic phase.Due to the limitation of the resolution of experimental instruments,it is not yet possible to obtain a clear shock wave front structure through experiments.By means of molecular dynamics(MD)simulation,we obtain the velocity and coordinate information of every atom in each system,then compare the plastic deformation behavior of the material under different impact conditions,and finally obtain the impact of the shock conditions on the structure of the shock wave front.

Effect of heat treatment on microstructure and properties of single crystal copper cold-welded joints

With the means of electron backscattered diffraction(EBSD),mechanical properties test and digital eddy current metal conductivity,the single crystal copper cold-welded joint was tested and analyzed,the structure change of cold-welded joint and the effect of heat treating on the structure and property of cold-welded joint were discussed.The results show that:The deformation area of the single crystal copper cold welded joint is broken,the crystalline grain at the interface of the joint is refined,and the single crystal structure is still maintained in the base metal area.The hardness of the deformation area increases greatly,the conductivity of the joint does not change much,and the tensile strength of the joint reaches about 70%of that of the base metal.At the interface of the heat treating joint,the single crystal structure of the deformation area and the base metal area are destroyed,and the grains grow up at the interface and the orientation is different.The hardness of the joint interface is much lower than that of the non-heat treating joint,the electrical conductivity of the joint is good,and the tensile strength of the joint is higher than that of the base metal.

CONTINUOUS CASTING TECHNOLOGY OF SINGLE CRYSTAL COPPER ROD

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9R structure in drawn industrial single crystal copper wires

By using transmission electron microscopy, the microstructures of drawn industrial single crystal copper wires produced by Ohno Continuous Casting(OCC) process were analyzed. The results show that the typical microstructures in the wires mainly include extended planar dislocation boundaries, a small fraction of twins and some dislocation cells sharing boundaries parallel to drawn direction. Besides the typical microstructures, 9R structure configurations were observed in the wires. The formation of 9R polytypes may be caused by the coupled emission of Shockley dislocations from a boundary.

Microstructure and texture evolution of cold drawing <110> single crystal copper

By means of electron backscattering diffraction and transmission electron microscopy the microstructure and texture of drawn single crystal copper with initial orientation （110） parallel to axial direction have been investigated in the present work. In or- der to analyze the effect of initial orientation on microstructure and texture of drawn copper, the results of the drawn （110） sin- gle crystal copper wires have been compared with （100） and （111） single crystal copper wires. It is found that the grain subdi- vision of （110） single crystal is more evident than that of （100） and （111）, and the textures consisting of （111） and （100） abruptly form in the drawn （110） single crystal. At high strains, due to shear strain, the distribution of fiber textures is imho- mogenous along the radial direction of drawn （110） single crystal copper wires. （100） is near the surface and （111） is at the center. The microstructure results of drawn （110） single crystal show that at low strains, it can be characterized as two kinds of geometrically necessary boundaries with noncrystalline character. At medium strains, S bands can be observed. At high strains, lamellar boundaries form. Mean misofientation and average spacing of dislocation boundary are larger in drawn （110） single crystal, as compared with （111） and （100）. In drawn （110） single crystal with high strains, the bimodal distribution forms at lower strains than in drawn （100） single crystal, which is because the dislocation boundaries with high angle are contributed by not only the boundary between （111） and （100） fiber textures but also the boundary in （111） or （100） texture.

Microstructure evolution of single crystal copper wires in cold drawing

The deformation microstructure evolution of single crystal copper wires produced by OCC method has been studied with the help of TEM, EBSD; OM. The results show that there are a small number of dendrites; twins in the undeformed single crystal copper wires. However, it is difficult to observe these dendrites in deformed single crystal copper wires. The structure evolution of deformed single crystal copper wires during drawing process can be divided into three stages. When the true strain is lower than 0.94, macroscopic subdivision of grains is not evident,; the microscopic evolution of deformed structure is that the cells are formed; elongated in drawn direction. When the true strain is between 0.94; 1.96, macroscopic subdivision of grains takes place,; the number of microbands located on {111}; cell blocks is much more than that with the true strain lower than 0.94. When the true strain is larger than 1.96, the macroscopic subdivision of grains becomes more evident than that with the true strain between 0.94; 1.96,; S-bands structure; lamellar boundaries will be formed. From EBSD analysis, it is found that part of 100 texture resulting from solidifying is transformed into 111; 112 due to shear deformation, but 100 texture component is still kept in majority. When the true strain is 0.94, the misorientation angle of dislocation boundaries resulting from deformation is lower than 14°. However, when the true strain arrives at 1.96, the misorientation angle of some boundaries will be greater than 50°,; the peak of misorientation angle distribution produced by texture evolution is located in the range between 25°; 30°.

Synthesis and Crystal Structure of Tetraaquacopper(II) Bis(5-fluorouracil-1-acetate) Tetrahydrate

The title compound, [Cu（C6H4N2O4F）2（H2O）4].4（H2O） I, has been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction method. It crystallizes in monoclinic, space group P21/c with a = 8.3041（17）, b = 12.045（2）, c = 11.077（2） A, β = 92.567（3）°, V= 1106.8（4） A^3, Mr = 581.89, Z= 2, Dc = 1.746 g/cm^3, F（000） = 598,μ（MoKa） = 1.090 mm^-1, the final R = 0.0296 and wR = 0.0806 for 3195 observed reflections with Ⅰ 〉 2σ（Ⅰ）. In the centrosymmetric compound I, each Cu（Ⅱ） ion is coordinated by six O atoms from two 5-fluorouracil-1-acetate anions and four water molecules, forming a six-coordinated octahedral environment. N-H…O and O-H…O hydrogen-bonding interactions are observed in the structure, leading to the formation of a three-dimensional network.

Synthesis and Crystal Structure of a New Three-dimensional Supramolecule of Copper(Ⅱ) Schiff Base Complex

A new three-dimensional supramolecule composed of copper-Schiff base complex, [Cu（naphdien）]Cl·H2O, where naphdien is Schiff base of 2-hydroxy-1-naphthaldehyde and diethylenetriamine, has been synthesized and determined by single-crystal X-ray diffraction. It belongs to the monoclinic system, space group P21/c, with a = 7.3490（15）, b = 7.0847（16）, c = 30.845（3）A, β= 95.33（3）°, V = 1599.0（5）A3, Z = 4, C15 H20ClCuN3O2, Mr = 373.33, De = 1.551 g/cm3, μ = 1.543 mm^-1, F（000） = 772, R = 0.0536 and wR = 0.0927 for 2788 unique reflections with 1659 observed ones （I 〉2σ（I））. In the crystal structure, mononuclear units [Cu（naphdien）]Cl·H2O are linked into a two-dimensional framework via strong hydrogen bonds, and extended into a three-dimensional supramolecular structure through π-π stacking interactions.

Synthesis and Crystal Structure of the Copper Complex {[Cu(CH_3COO)_2(bbtz)](H_2O)_2}_n

The new copper complex { [Cu（CH3COO）2（bbtz）]（H2O）2 }, 1 （bbtz = 1,4-bis（ 1,2,4- triazol-1-ylmethyl）benzene） was synthesized and the structure was determined by single-crystal X-ray diffraction. Crystal data： C16H22CuN6O6, monoclinic, space group P21/n, a = 12.589（5）, b = 6.455（2）, c = 12.677（5） A, β= 98.748（9）°, V= 1018.2（7） A^3, Mr = 457.95, Z = 2, Dc= 1.494 g/cm^3, F（000） = 474, μ = 1.118 mm^-1, R = 0.0463 and wR = 0.0939 for 1971 observed reflections with I 〉 2σ（I）. The crystal structure of 1 is a one-dimensional chain via the bridging flexible ligand bbtz.

Synthesis and Crystal Structure of Binuclear Copper (Ⅱ) Complex Containing (Dimethylaminomethyl)ferrocene

A binuclear complex including ferrocenyl, Cu2{Fe(C5H5)[C5H4CH2N(CH3)2]}2 (CH3COO)4, was synthesized and characterized by X-ray diffraction. The title complex crystallizes in triclinic, space group P with a = 8.2779(8), b = 9.4830(8), c = 12.262(1) ? = 81.079(5), b = 80.620(4), g = 78.960(4), V = 924.4(1) 3, Z = 1, C34H46Cu2Fe2N2O8, Mr = 849.51, Dc = 1.526 g/cm3, l(MoK) = 0.71073 ? ?= 1.954 mm-1, F(000) = 438, R = 0.0297 and wR = 0.0901. Both cyclopentadienyl rings in each dmaf (dmaf = (dimethylaminomethyl)ferrocene, Fe(C5H5)- [C5H4CH2N(CH3)2]) have an eclipsed conformation. The binuclear molecule has a crystallographic centrosymmetry; four acetates and two Cu atoms form a cage structure with the distance between two neighboring Cu atoms of 2.655(1) .

Synthesis and Crystal Structure of Copper(Ⅱ) Compound with Didentate Schiff-base Ligand

The title complex [Cu(L)2] (HL=4-salicylideneamino-3,5-dimethanol-1,2,4-triazole) was synthesized by the reaction of Cu(CH3COO)22H2O with 4-salicylideneamino-3,5-dimethanol- 1,2,4-triazole in the methanol. The single-crystal X-ray study reveals that the compound crystallizes in monoclinic, space group P21/n with a = 11.746(5), b = 8.145(3), c = 12.786(5) ? b = 106.64(1), V = 1172(1) ?, Z = 2, Dc = 1.581 g/cm3, m = 0.989 mm-1, F(000) = 574, C22H22Cu- N8O6, Mr = 558.02, T = 293(2) K, R = 0.0394 and Rw = 0.0835 for 2376 observed reflections with I > 2s(I). The complex comprises a four-coordinated copper(II) center, with an N2O2 planar coordi- nation environment. The molecules are connected by hydrogen bonds to form one-dimensional chains which are further linked to form a two-dimensional plane.

Dinuclear Copper(Ⅱ) Complex with a New Polycarboxylate Ligand:Syntheses,Characterization and Crystal Structure

A dinuclear copper（Ⅱ） complex,[Cu2（HL）2（H2O）6] 1（H3L = 2,4,6-tri（3-carboxy-phenylthio）-1,3,5-triazine）,was synthesized hydrothermally and characterized by single-crystal X-ray diffraction,IR and thermal analysis.Single-crystal X-ray diffraction reveals that complex 1 is a dinuclear copper（Ⅱ） complex,which is further extended to a 3D network by weak interactions such as O…H-O hydrogen bonds and noncovalent S...S interactions.The crystal of compound 1 belongs to monoclinic,space group C2/c,with a = 50.15（2）,b = 6.789（3）,c =15.667（8） ,β = 90.588（9）o,V = 5334（4） 3,Z = 4,C48H38Cu2N6O18S6,Mr = 1306.28,Dc = 1.627 g/cm3,F（000） = 2664,Rint = 0.0631,T = 293（2） K,μ = 1.112 mm-1,the final R = 0.0661 and wR = 0.1850 for 3782 observed reflections with I 2σ（I）.

Synthesis,Crystal Structure and Catalytic Performance of the Trifluoro-substituted Mono(β-diiminato)Copper(Ⅱ)Complex

Two novel copper complexes with methyl or trifluoro-substituted mono-β-diiminato ligands and one acetoxyl anion were synthesized and characterized by IR spectroscopy and elemental analysis for the first time. The structure of complex 2 bearing trifluoro substituents was further confirmed by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.377（4）, b = 11.727（6）, c = 12.913（7） ？, α = 116.569（6）, β = 98.829（7）, γ = 96.520（6）°, V = 966.2（8） ？3, Z = 2, Mr = 479.86, Dc = 1.649 g/cm3, F（000） = 482, μ = 1.205 mm-1, the final R = 0.0370 and w R = 0.0903 for 3430 observed reflections with I 〉 2σ（I）. These mono-β-diiminato copper complexes can effectively catalyze methacrylate（MA） polymerization when activated by MMAO. The introduction of fluoro groups into the N-aryl ring of β-diiminato ligands can greatly increase the catalytic activity of copper complexes as well as the molecular weight of PMA.

Effect of electric pulse on the crystal structure of solidified copper ingots

To obtain advanced quality pure copper, the microstructure of solidified copper was optimized by imposing electric pulse on liquid copper in this study. Experiments were performed to determine the effect of electric pulse voltage, arrangement mode of electrodes, and energy input on the microstructure of solidified copper. The results show that, when the energy input of electric pulse is bigger than 28.95 kJ per ton copper, the percent of fine grains increases noticeably with the increase of energy input; but when the energy input of electric pulse is smaller than 28.95 kJ per ton copper, the percent of fine grains decreases with the increase of energy input. The influence order of above factors on grain refinement is electric pulse voltage 〉 arrangement mode of electrodes 〉 energy input. According to the above experimental results, the optimum process conditions are chosen as the voltage being 400 V and the energy input greater than 28.95 kJ per ton copper. Meanwhile, the best arrangement mode of electrodes should be that, one electrode is immerged in the middle of liquid copper in the crystallizer, and the other is connected to the inner wall of the crystallizer, which is divided into two electrode poles for the symmetrical electric field distribution.

Synthesis,Crystal Structure and Antibacterial Activity of a New Ternary Copper(Ⅱ) Complex with 2,6-Pyridinedicarboxylic Acid and 1,10-Phenanthroline

A new ternary copper（Ⅱ） complex, [C43H27Cu2N7O5][C14H6CuN2O8]＇6.5H2O, has been synthesized by the reaction of copper sulfate, 2,6-pyridinedicarboxylic acid and 1,10- phenanthroline （phen）, and characterized by elemental analysis, IR, UV and X-ray single-crystal diffraction. It crystallizes in triclinic, space group P1, with a = 14.379（5）, b = 15.510（5）, c = 15.835（6） A, a = 78.567（6）, β = 63.594（6）, y = 81.287（6）°, V= 3092.1（19） A3, C57H46Cn3N9O19.5, Mr = 1359.54, Z = 2, Dc = 1.446 Mg/m3, λ（MoKa） = 0.71073 A,μ = 1.101 mm^-1, F（000） = 1362, S = 1.071, the final R = 0.0718 and wR = 0.11960 for 10705 observer reflections （I 〉 2σ（I））. The structure unit of the title complex consisfs of a mononuclear part and a di-nuclear part, and the three copper ions show three coordination modes. Each 6-coordinated geometry of the Cu atom is a distorted octahedral coordination geometry. The 3D supramolecular system is formed by the hydrogen bond O-H-O and π-π stacking interaction between neighboring single cells. The antibacterial activity of the title complex is also studied.

Synthesis and Crystal Structure of a Novel Bis(chlorido)-bridged One-dimensional Chain-like Copper(Ⅱ) Polymer

A copper（Ⅱ） complex [LCu2Cl4]n was synthesized by a new bis-Schiff base ligand containing quinoline unit, 1,4-bis[2-（4-fluorophenyl）iminomethyl-8-quinolinoxy]butane（L）. X-ray crystal structure shows that it is a binuclear complex, and the crystal belongs to the triclinic system, space group P1, with a = 9.387（2）, b = 9.968（2）, c = 10.291（2） ？, α = 87.532（3）, β = 63.762（2）, γ = 86.628（3）o, V = 862.1（3） ？^3, Z = 1, Dc = 1.640 Mg/m^3, F（000） = 428, R = 0.0416 and wR = 0.1141. Each Cu（Ⅱ） metal ion coordinates with a quinoline N atom, an imine N atom, an ether oxygen atom and three chlorides, forming a distorted six-coordinated octahedronal structure. Each copper（Ⅱ） complexation unit links with one of the adjacent ligand copper complexation units through the chlorido bridging groups, thus generating an infinite one-dimensional chain structure. Such 1D chains further construct a 2D network structure by π-π stacking interactions.