Microstructure and properties of Cu-2.8Ni-0.6Si alloy

The phase transformation behavior and heat treatment response of Cu-2.8Ni-0.6Si （wt%） alloy sub- jected 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 TR （500-550 ℃） in Cu-2.8Ni-0.6Si alloy, the transformation undergoes spinodal decomposi- tion, DO22 ordering, and δ-NiaSi phase. On aging at the temperature above TR （500-550 ℃）, the transformation products were precipitations of 8-Ni2Si. The free energy versus composition curves were employed to explain the microstructure observations.

Microstructure and physical properties of Cu-2.3Ni-0.5Si alloy with thermo-mechanical treatment

For Cu-Ni-Si alloys,cold rolling is usually performed after solution treatment to enhance physical properties such as strength and electrical conductivity during the aging process.This paper reports the variation in microstructure and physical properties during the aging process of Cu-2.3Ni-0.5Si alloy cold-rolled at room temperature(RT) and cryogenic temperature(CT).When aged at 450℃ for 2 h,RT-rolled samples exhibited a maximum hardness of HV5234 with an electric conductivity of 39.9% IACS.For CTrolled samples,the peak hardness was achieved when the samples were aged at 450% for 1 h.

Mechanical properties and microstructure of rolled and electrodeposited thin copper foil

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 rol- led 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 [^-fiber texture, and the electrodeposited copper foils have random crystalline orientations. It was also observed that the rolled foils have packed grains, and elec- trodeposited foils have equiaxial grains. The uniform fine grain size and a few substructures of Japanese electrode- posited foils are major reasons for their higher elongation.

Microstructural evolution and properties of a Cu-Cr-Ag alloy during continuous manufacturing process

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 ascast 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.

Microstructure of phases in a Cu–Zr alloy

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 plateliked Cu5Zr phases with fcc structure are found in the matrix, in which habit plane is parallel to {111}a plane of the matrix.Between the copper matrix and Cu5Zr phase,there exists an orientation relationship of [112]a|| [011]Cu5Zr;(111)a||(111)Cu5Zr. The space structure model of Cu5Zr phase can be established.

Improving interface adhesion in TiNi wire/shape memory epoxy composites using carbon nanotubes

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 astreated 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.

Antibacterial property,corrosion and discoloration resistance of pure copper containing Zn or Ni

This study focused on the effects of Zn and Ni addition on the antibacterial properties and corrosion resistance of copper alloys.The antimicrobial properties of copper and copper alloys were evaluated using Escherichia coli ATCC8739 bacterial strain by employing the overlay and plate counting methods.

Interface evolution of Cu-Ni-Si/Al-Mg-Si clad composite wires after annealing

Interface micros tructures of Cu-Ni-Si/Al-MgSi 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 Al_(4)Cu_(9),AlCu and Al_(2)Cu identified by energy-dispersive spectroscopy(EDS)and transmission electron microscopy(TEM).The growth activation energies of total IMCs,Al_(2)Cu,AlCu and Al_(4)Cu_(9),are 98.8,69.4,101.3 and 137.1 kJ·mol^(-1),respectively.The higher growth activation energy of Al_(4)Cu_(9)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 Al_(2)Cu and AlCu is more active than that in Al_(4)Cu_(9).The higher growth rate of Al_(4)Cu_(9)may be caused by the long concentration range.