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Microstructure evolution and properties of a Cu–Cr–Ag alloy during the continuous manufacturing process were investigated in detail by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in the study. The Cu–Cr–Ag alloy rod with uniform compositions is fabricated by upward continuous casting technology. Few of the Cr phases are observed in the as-cast alloy. During the continuous extrusion process, the severe shear deformation and the dynamic aging occur. The average grain size of as-extruded alloy is much smaller than that of as-cast alloy. Both fcc and bcc Cr precipitates appear in the matrix. The interaction mode between dislocations and precipitates can be identified as Orowan bypass mode according to the TEM observations. The overall difference in the yield strength between as-cast and as-extruded Cu–Cr–Ag alloy is attributed to solid solution strengthening, grain refinement strengthening, precipitation hardening and working hardening.

The Cr precipitation sequence in Cu-Cr-Zr-Ag alloy during the aging process at 450°C could be obtained by Transmission electron microscopy (TEM) and High-resolution transmission microscopy (HRTEM) in the study. The strengthening curve shows a unimodal type and the tensile strength trends to peak when the aged for 4h. The Cr phase transformation of Cu-Cr-Zr-Ag aged at 450°C is supersaturated solid sloution→G.P zones→fcc Cr phase→order fcc Cr phase→bcc Cr phase. The orientation relationship between bcc Cr precipitates and the matrix change from cube-on-cube to NW-OR.

The coarsening behavior of (Ni, Co)2Si particles in Cu–Ni–Co–Si alloy was investigated by experimental observations and coarsening kinetics calculations when aged at 450, 500, 550 and 600 °C for different durations. The results show that the critical particle radius for coherence mismatch is found to be 10.3 nm, and particles larger than 25 nm are generally semi-coherent. The relationship of (Ni, Co)2Si particles size and aging time follows Lifshitz, Slyosov and Wagner (LSW) theory. The particle size distributions fit well to the LSW theoretical distribution. The activation energy for (Ni, Co)2Si coarsening is accurately determined to be (216.21 ± 5.18) kJ·mol−1 when considering the effect of temperature on the solution concentrations in matrix. The coarsening of (Ni, Co)2Si particles in Cu–Ni–Co–Si alloy is controlled by diffusion of Ni, Co and Si in Cu matrix. The growth of particles for long durations suggests that vacancies can be trapped within the structure for long time despite their mobility.

Interface microstructures of Cu–Ni–Si/Al–Mg–Si clad composite wires during isothermal annealing from 623 to 773 K were investigated. The composite wires were fabricated by a drawing process. The evolution of intermetallic compounds (IMCs) was analyzed. A continuous IMCs layer forms only after annealing for 1 min, which may be due to more IMCs nucleation points generated by deep drawing process. IMCs consist of Al4Cu9, AlCu and Al2Cu identified by energy-dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The growth activation energies of total IMCs, Al2Cu, AlCu and Al4Cu9, are 98.8, 69.4, 101.3 and 137.1 kJ·mol−1, respectively. The higher growth activation energy of Al4Cu9 results in the higher growth rate under high temperature. However, the average interdiffusion coefficient for each IMC calculated by Wagner method shows that interdiffusion in Al2Cu and AlCu is more active than that in Al4Cu9. The higher growth rate of Al4Cu9 may be caused by the long concentration range.

In this paper, nominal composition of Cu-0.3Cr-0.07Ag (at%) was designed. The high temperature properties and microstructure were investigated by Transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that the tensile strength of CuCrAg decreases as temperature rises, which was associated with the coarsen precipitates according to TEM observation. Furthermore, observations of fracture morphology reveal that the mechanism transforms into brittle fracture from ductile fracture at elevated temperature. Creep curves were found to vary as a function of applied stress and temperature, the stress exponent values are 8.7, 4.6, 4.3 at 673K, 773K, 873K respectively. The mechanism is dislocation climbing at 773K and 873K while creep behavior at 673K could be explained by the invariant substructure model.

In order to increase both the interfacial strength and interphase region strength between TiNi wires and shape memory epoxy, a novel interface structure including aminated CNTs was designed. The morphology shows that after electroplating and etching, continuous and homogeneous concave–convex layers form on the surface of as-treated TiNi wires, meanwhile aminated CNTs were planted on the surface which could react with shape memory epoxy at the interface region. The interfacial shear strength increases first with the CNT content rising but then a dramatic drop happens, and the maximum is obtained at CNT content of 0.6 g·L−1, which is about twice the result of acid etching TiNi wires.

Copper-clad aluminum (CCA) composite wires have been widely used in cable industry. Especially for the application in aerospace, the light weight character of wires is particularly important. To improve the mechanical properties of wires, Cu-Ni-Si alloy and Al-Mg-Si alloy are employed to replace pure copper and pure aluminum, respectively. The objective of this work is to find the appropriate annealing treatment conditions to produce the Cu-Ni-Si/Al-Mg-Si clad composite wires with optimal combination properties. The wires were fabricated by a drawing process and heat treatment at different temperatures and times. Mechanical and electrical properties dependent on outer Cu-Ni-Si, internal Al-Mg-Si and interface properties, are characterized and analyzed. The fracture behavior of Cu-Ni-Si/Al-Mg-Si clad composite wires was studied together with the stress-strain curves of the composite wires.

Commercial grade rolled and electrodeposited copper foils from Japan and China were selected, and their mechanical properties and microstructure were investigated. It was observed that there are notable differences in fracture strength, elongation at break and hydrophilicity between rolled and electrodeposited copper foils. The rolled copper foils have higher tensile strength, lower ductility and larger static contact angle than electrodeposited copper foils. The rolled copper foils contain a β-fiber texture, and the electrodeposited copper foils have random crystalline orientations. It was also observed that the rolled foils have packed grains, and electrodeposited foils have equiaxial grains. The uniform fine grain size and a few substructures of Japanese electrodeposited foils are major reasons for their higher elongation.

The rare earths are important modifier in copper alloy. This paper did research about the effect of Ce on microstructures and mechanical properties of HMn64-8-5-1.5 brass. The addition of Ce can refine the matrix grain of as-cast and extruded HMn64-8-5-1.5 brass, reduce the size and quantity of big hard phase , and contribute to the extraction of tiny hard phase, such as Mn5Si3 phase. When given tensile stress, hard phases can produce crack initiations. The addition of rare earth Ce can increase the number of hard phase and thus produce more crack initiations, so that the mechanical properties of HMn64-8-5-1.5 brass can be reduced.

The morphology and crystallography of phases in the Cu-0.12 % Zr alloy were investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), and high-resolution transmission electron microscope (HRTEM). The results show that the as-cast microstructure of Cu–Zr alloy is mainly Cu matrix and eutectic structure which consist of Cu and Cu5Zr phases with a fine lamellar structure. The disk-shaped and plate-liked Cu5Zr phases with fcc structure are found in the matrix, in which habit plane is parallel to {111}α plane of the matrix. Between the copper matrix and Cu5Zr phase, there exists an orientation relationship of $$[112]_{\upalpha } \parallel [011]_{{{\text{Cu}}_{ 5} {\text{Zr}}}} ,(\overline{1} \overline{1} 1)_{\upalpha } \parallel (11\overline{1} )_{{{\text{Cu}}_{ 5} {\text{Zr}}}}$$ . The space structure model of Cu5Zr phase can be established.

The precipitation process of aged Cu–Ni–Be alloy was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The tensile strength, yield strength, and electronic conductivity of this alloy after aging were also studied. The precipitation sequence of the C17510 alloy aged at 525 °C is supersaturated solid solution→ G.P zones→ γ″→ γ′→ γ. This transformation can be achieved by the accumulation of Be-atom layers. The G.P zones are composed of disk-shaped monolayers of Be atoms, which are formed on (001) matrix planes. The intermediate γ″ precipitate is nucleated in the G.P zones. The γ″ and γ′ precipitates have the same orientation relationship with matrix, e.g., (110)P‖(100)M,[001]P‖[001]M. The tensile strength of specimen shows a maximum during the aging process and then continuously decreases if the specimen is over aged. The strengthening effect of γ′ phase precipitated in aging at 525 °C for 4 h is calculated to be 436 MPa according to the Orowan strengthening, which is quite consistent with the experimental data.

The phase transformation behavior and heat treatment response of Cu–2.8Ni–0.6Si (wt%) alloy subjected to different heat treatments were studied by X-ray diffraction, transmission electron microscopy observation, and measurement of hardness and electrical conductivity. The variation of hardness and electrical conductivity of the alloy was measured as a function of aging time. On aging at the temperature below T R (500–550 °C) in Cu–2.8Ni–0.6Si alloy, the transformation undergoes spinodal decomposition, DO22 ordering, and δ-Ni2Si phase. On aging at the temperature above T R (500–550 °C), the transformation products were precipitations of δ-Ni2Si. The free energy versus composition curves were employed to explain the microstructure observations.

The one- and two-dimensional spin S = 1 2 anisotropic Heisenberg ferromagnet model is studied by the double-time Green's function method within the random phase approximation. The magnetization, susceptibility and transverse correlation functions are found to be dependent on the anisotropy. Our result shows that the position and height of maximum of the susceptibility yields the power-law behaviors with respect to the magnetic field. It does not support the 2 3 power law which is obtained from the mean-field Landau's theory. For the isotropic case, our results are in agreement with the results obtained by other theoretic techniques. For S = 1 2 ferromagnetic chain system (C 6 H 11 NH 3 )CuBr 3 , the crossover of the anisotropic system to XY -kind behavior is expected at low temperature T ≈ 5.5 K , which agrees with experiment results and theoretical calculations.

The location and height of the susceptibility maximum for anisotropic one and two-dimensional spin S ¼ 12 Heisenberg models areinvestigated by using the Green’s function treatment within the random phase approximation. The results are fitted to the power lawbehaviors, T wm T 0 ¼ ah g and wðT wm Þ¼bh b , in the high field. And the exponents g;b are found to be dependent of the anisotropy. Ourresults do not support the 23 power laws which are obtained from the mean-field Landau’s theory. For the isotropic and Ising cases, theexponents g;b which are in agreement with the results by other theoretic techniques.r 2007 Elsevier B.V. All rights reserved. PACS: 64.60.HtKeywords: Heisenberg ferromagnet; Anisotropy; Susceptibility 1. IntroductionThe field-induced effect on low-dimensional magnetsdescribed by quantum Heisenberg models have attractedincreasing attention [1–7]. Recently, the field dependence ofthe position of the susceptibility maximum wðT wm Þ has beendiscussed in connection with the electrical resistivity rðTÞof La