Recrystallization Of Copper Research Articles

Measurement of the Secondary Recrystallization in Copper by X-ray Diffraction and ECP

Etude du processus de recristallisation par analyse des textures, des microstructures et des orientations de grains. La recristallisation secondaire est affectee par la taille des grains initiale avant le laminage, par les conditions de laminage. Determination des relations d'orientation entre recristallisation primaire et secondaire. Discussion concernant ces relations, basee sur le modele de reseau de site de coincidence

Microscopically-Determined Static Recrystallization of Copper During Holding Without Stress or with Stress Relaxation After Hot Working

After deformation to 0.15 in the range 450–540°C and 1.8 × 10−3 to 1.8 s−l in compression or torsion, the recrystallization of ETP Cu determined microscopically is compared to the restoration measured mechanically during intervals of holding at the deformation temperature under both stress-free and stress-relaxation conditions. Recrystallization is initially much slower than softening, the difference being due to recovery, but finally they become equal at about 85%. TEM substructures sharpen considerably during intervals up to 100 s. Recovery and recrystallization occur more rapidly as strain rate and temperature rise in both modes of holding, but in stress relaxation the former is slowed down and as a result the latter is speeded up.

Microscopically-Determined Static Recrystallization of Copper During Holding Without Stress or with Stress Relaxation After Hot Working

Abstract After deformation to 0.15 in the range 450–540°C and 1.8 × 10−3 to 1.8 s−l in compression or torsion, the recrystallization of ETP Cu determined microscopically is compared to the restoration measured mechanically during intervals of holding at the deformation temperature under both stress-free and stress-relaxation conditions. Recrystallization is initially much slower than softening, the difference being due to recovery, but finally they become equal at about 85%. TEM substructures sharpen considerably during intervals up to 100 s. Recovery and recrystallization occur more rapidly as strain rate and temperature rise in both modes of holding, but in stress relaxation the former is slowed down and as a result the latter is speeded up.

Improvement in the heat resistance of conductor copper alloyed with zirconium and magnesium

Using conductor materials suitable for operating at elevated temperatures is an increasingly important problem. One of the main conductor materials is copper, and it is possible to increase the strength properties of copper without a marked reduction in ductility by work hardening it with small degrees of deformation, however it is practically impossible to retain these properties at elevated temperatures since pure copper has a low recrystallization temperature which leads to its loss of strength. By increasing the recrystallization temperature for copper it is possible to extend the temperature range for operating conductors in the direction of higher temperatures. Since there is little information about the combined effect of microadditions of zirconium and magnesium on the recrystallization of copper with a varying degree of work hardening, the goal of this study was to determine the effect of microalloying zirconium and magnesium on the temperature range of loss of strength in copper.

Lewis-base adducts of Group 1B metal(I) compounds. Part 17. Synthesis and crystal structures of adducts of copper(I) cyanide with nitrogen bases

Compounds of the type [Cu(CN)Ln][L = diethylamine, (1), triethylamine, (2), 4-methylpyridine, (3), or 1,10-phenanthroline, (4)] have been synthesized by recrystallization of copper(I) cyanide from (or with) the parent base and their crystal structures have been determined by single-crystal X-ray diffraction methods; n= 1 except in the case of (3) where n= 1.5. Crystals of (1) are monoclinic, space group P21/n, with a= 15.108(7), b= 7.321(5), c= 13.699(6)Å, β= 103.00(4)°, and Z= 8; R was 0.044 for No= 871 independent ‘observed’ reflections. For (2), crystals are orthorhombic, space group Pnma, with a= 9.501(4), b= 8.921(4), c= 11.279(5)Å, and Z= 4; R= 0.039, No= 369. For (3), crystals are monoclinic, space group Cc, with a= 9.587(3), b= 16.326(4), c= 14.022(4)Å, β= 109.38(2)°, and Z= 4; R= 0.031, No= 1 070. For (4), crystals are trigonal, space group P31, with a= 9.175(5), c= 11.753(8)Å, and Z= 3; R= 0.041, No= 812. All complexes are one-dimensional polymers, that in (2) being disposed completely in a mirror plane except for the substituent alkyl groups. Copper atoms in (1) and (2) are trigonally planar co-ordinated by C,N(cyanide) and N(base), as is one of the two copper atoms in (3); the other copper atom in (3) is unusual, being four-co-ordinated pseudo-tetrahedrally by C,N(cyanide) and two N(base). A similar copper environment is found in (4).

Lewis-base adducts of Group 1B metal(I) compounds. Part 16. Synthesis, structure, and solid-state phosphorus-31 nuclear magnetic resonance spectra of some novel [Cu4X4L4](X = halogen, L = N, P base)‘cubane’ clusters

Recrystallization of [Cu4l4(PPh3)4] from toluene has yielded a new polymorph of that compound, (1), which has been shown by single-crystal X-ray diffraction analysis to have a tetrametallic ‘cubane’ structure rather than the expected ‘step’ structure. Crystals are monoclinic, space group P21/n, with a= 19.47(1), b= 26.94(1), c= 13.528(5)A, β= 98.98(4)°, Z= 4 tetramers; R was 0.06 for No= 3 681. Cu–I distances range from 2.653(3) to 2.732(3)A, with Cu ⋯ Cu 2.874(5)–3.164(4) and I ⋯ I 4.234(2)–4.496(3)A. All adducts of stoicheiometry [M4X4(PPh3)4](M = Cu or Ag; X = Cl, Br, or I) have now been synthesized and structurally characterized in a cubane configuration. Recrystallization of copper(I) chloride and bromide from triethylamine also yields tetrameric cubane 1 : 1 adducts [X = Cl (2) or Br (3)], as does the reaction of copper(I) chloride with the very bulky ligand 2-[bis(trimethylsilyl)methyl]pyridine, to give [Cu4Cl4(tmspy)4](4). These three complexes have also been crystallographically characterized, (2) and (4) being the first reported cubane type tetramers for the copper(I) chloride–nitrogen base system. Complexes (2) and (3) are isostructural with their triethylarsine and -phosphine counterparts, being cubic, space group I3m, with a= 12.162(5)A in (2) and 12.368(3)A in (3); Z= 2 tetramers. Cu–Cl,Br distances are 2.441(4) and 2.537(3)A respectively. For (4), the crystals are tetragonal, space group I41/a, with a= 18.620(4), c= 20.079(5)A, Z= 4 tetramers. Although the Cu4Cl4 cubane core of the molecule has crystallographically imposed symmetry, the geometry is very unsymmetrical as a consequence of the ligand bulk, with Cu–Cl 2.225(2)–2.636(2), Cu ⋯ Cu 2.960(2)–3.194(2), and Cl ⋯ Cl 3.838(3)–3.866(3)A. Residuals R for (2), (3), (4) were 0.040, 0.038, and 0.040 respectively for No= 136, 136, and 1 008 ‘observed’ reflections. The solid-state 31P n.m.r. spectra of the triphenylphosphine cubane clusters show significant differences to those with a ‘step’ geometry; these differences are related to the crystallographic environment of the phosphorus nuclei.

Effect of prior cold work on the influence of electric current pulses on the recrystallization of copper

Les resultats experimentaux obtenus montrent que l'application concurrente d'impulsions de courant electrique pendant le recuit isochrone du cuivre deforme a froid augmente les vitesses de restauration et de recristallisation et conduit a un affinement de la grosseur du grain et a une reduction de la frequence de maclage

Effect of initial grain size on dynamic recrystallization of copper

AbstractOxygen free high conductivity (OFHC) and electrolytic tough pitch (ETP) copper specimens of different grain sizes (10–800 μm) were tested at various constant true strain rates in a modified Instron testing machine. The temperature range investigated was 725–1075 K. The effect of initial grain size on the transition from multiple to single peak flow was studied. The dependence of the stable dynamic grain size on the temperature corrected strain rate and the steady state stress was determined, as were the density of twins and of deformation bands. The density of twins decreased as the initial grain size was increased and when the recrystallization mechanism changed from static to dynamic. The density of deformation bands increased markedly with initial grain size. As the deformation bands are preferential nucleation sites for new dynamic grains, the results indicate that the initial effective grain size D o * </mm...

A comment on “effect of electric current pulses on the recrystallization of copper”

A comment on “effect of electric current pulses on the recrystallization of copper”

Effect of electric current pulses on the recrystallization of copper

Effect of electric current pulses on the recrystallization of copper

Dynamic Recrystallization in Copper and a-Brass During High Temperature Tensile Tests

Dynamic Recrystallization in Copper and a-Brass During High Temperature Tensile Tests

The effect of small amounts of ag, se, and sn on the recrystallization of copper

This study is a laboratory investigation of the effects of small amounts of Ag, Se, and Sn singly and in combination on the recrystallization of copper. Pre-anneal solution heat treatments were given to copper wires to establish various amounts of the impurity element in solid solution in the wires. The wires were then cold drawn in tungsten carbide dies and given recrystallization anneals in low temperature salt baths. Degree of re-crystallization was determined by yield point measurements. The recrystallization behavior was found to obey the Avrami equation with the exponent in the Avrami equation indicating unidirectional recrystallization. Yield points did not vary with impurity concentration in the concentration ranges studied. The greatest increase in recrystallization temperature was found for tin additions. Activation energies and recrystallization temperatures for the various concentrations of impurity elements are given in the paper. Increased amounts of second phase precipitates had little effect on the recrystallization temperature with the greatest effect occurring for the impurity elements in solid solution.

Interaction of cold work, recovery, recrystallization, and precipitation in heat-treatable copper alloys

Inhibition of recrystallization in copper and its alloys can be caused by small quantities of foreign elements such as Ag, P, Cd, Mg, and Sn in solid solution in the copper. These elements segregate at dislocation and grain boundaries, thereby inhibiting migration. The effect of cold work is a simple function of the quantity of soluble addition and the degree of cold work. The situation is more complicated for precipitation-hardened alloys because cold work, precipitation, and softening interact. In starting with the supersaturated solid solution which has been severely cold worked, heat treatment will lead to both precipitation and recrystallization. However, by means of precipitation treatment before cold working, it is possible to slow down, and even halt, normal recrystallization; this treatment leads to the formation of a critical distribution of precipitates ('dispersoid') which effectively halts both dislocation and grain-boundary movement. Cu–Ti, Cu–Zr, Cu–Fe, and Cu–Co alloys were studied for different sequences of heat treatment and cold working and the following characteristics are described: (a) a very small residual quantity of soluble Zr suffices to maintain the softening temperature above 400°–500°C; (b) soluble Cr also inhibits the softening of Cu, although larger amounts are required than for Zr,’ (c) fine precipitates of Cr in the form of a critical dispersion are also effective for retaining cold working; (d) iron in solid solution has practically no effect on the softening temperature of copper.

Effects of the Rolling Procedures on the Recrystallization of Copper

Effects of the Rolling Procedures on the Recrystallization of Copper

A study of the nucleation of recrystallization using HVEM

Direct observations have been made of recrystallization in copper and a copper-phosphorus alloy by annealing specimens of the cold worked materials inside the high voltage electron microscope (HVEM). Nucleation of recrystallised grains was observed to occur by growth from suitable long subgrains by bulging out of their boundaries. In addition, it was observed that growing recrystallised grains could sometimes ‘catalyse’ nucleation of other grains when they impinged upon certain subgrains. These and other observations are discussed in the light of current theories of nucleation.

Dynamic Recrystallization in Copper and Mild Steel during High Temperature Torsional Deformation

The high temperature deformation of copper and mild steel has been studied at the homologous temperatures ranging from 0.5Tm (407°C) to 0.9Tm (948°C) for copper and from 0.7Tm (989°C) to 0.9Tm (1350°C) for mild steel under the constant true strain rate from about 10-3/sec to 30/sec in torsion. From the determination of their stress-strain behaviors and optical microstructural observations, the rate controlling mechanisms of the dynamic restoration process responsible for the occurrence of steady state deformation were investigated.The flow curves of the both materials exhibited the maxima, after which the flow stress decreased to a steady state value. It is clear from the above observations that dynamic recrystallization occurs at strains greater than a critical value and the recrystallized grain size depends only on the flow stress.The maximum flow stress data for both materials were plotted against the temperature compensated strain rate, using the activation energy for self diffusion. The form of strain rate dependence of the maximum flow stress in copper was similar to those found in a number of materials, studied over a wide range of strain rate: below a critical stress, that is approximately 10kg/mm2 in this case, a power law was observed with a stress exponent of 6.5, and above this critical stress a steeper stress dependence occurred. The stress exponent for mild steel was about 5.5 in the temperature range studied, as a straight line was obtained when the temperature-compensated strain rate was plotted against the maximum flow stress. The similar dependence was observed for the steady state flow stress when this condition was achieved.The dynamically recrystallized grain size of a copper specimen which deformed in each testing condition was measured by using the line intercept technique, from which the average recrystallized grain size (d) was determined. When the reciprocal grain size (1/d) was plotted against Zener-Hollomom parameter, a straight line was obtained. Therefore, it is confirmed that the operative restoration process during the high temperature deformation of copper is the dynamic recrystallization, since there is a constant relationship between the recrystallized grain size and deformation parameters.From the similarity in the stress-strain behaviors of copper and mild steel and the metallographic observations, it is reasonable to consider that the restoration process of mild steel in γ-range is dynamic recrystallization.

Recrystallization of copper under hydrostatic pressure up to 15 kbar

Recrystallization of copper under hydrostatic pressure up to 15 kbar

Recrystallization of copper under hydrostatic pressure up to 15 kbar

Hydrostatic pressure (up to 15 kbar) during annealing results in retardation of recrystallization during initial recrystallization of copper; the rate of nucleation and growth of new grains are both retarded. The effect of pressure on the nucleation rate is extremely high and a finer crystalline structure results during annealing under pressure.

Dynamic Recrystallization of Copper during Hot Torsion

AbstractTubular specimens of oxygen-free, high-conductivity copper have been deformed by hot torsion at 800° C (1073 K) (O.8T m ) or at 950° C (1323 K) (0.9T m ) at strain rates of 3.7–11.1 S−1 to true strains of ∼ 30. The specimens were quenched to room temperature in 3 s under one of two conditions: stopping the deformation and then quenching immediately, or quenching followed quickly by stopping the deformation. The resulting structures were examined by optical and transmission electron microscopy. The specimens quenched after stopping the deformation had recrystallized statically (subsequent to deformation) during cooling. The specimens deformed without stopping until quenched had not recrystallized statically but retained the as-worked grains that formed by dynamic recrystallization (concurrent with deformation). Since these grains nucleated at different times during the deformation, they contained dislocation substructures of varying densities. The theories of dynamic and static recrystallization ar...

The Influence of Ultrasound on the Kinetics of Recrystallization in Copper

AbstractThe influence of 20 kHz acoustic oscillations on the recrystallization kinetics of oxygen-free, high-conductivity copper has been investigated. Resonance standing waves with a maximum acoustic stress amplitude of 3.2 × 108 dyn/cm2 (4640lbf/in2) were developed in half-wavelength-long specimens. Ultrasound caused a great increase (30–100 times) in the recrystallization rate, the degree of acoustic enhancement being proportional to the acoustic stress amplitude. Ultrasound did not alter the form of the time-dependence of the nucleation and growth rates for recrystallization, but did decrease the apparent activation energy for recrystallization from 31.5 kcal/mol (132 kJ/mol) (without acoustic energy) to 17.0 kcal/mol (71 kJ/mol).