Effect of Cu additive on the structure and magnetic properties of (CoPt)_(1-x)Cu_x films

CoPt thin films with various Cu contents varying from 0 vol.% to 21.5 vol.% were deposited on glass substrates by magnetron sputtering. The effects of Cu additive on the structural and magnetic properties and the ordering temperature of CoPt films were investigated in detail. The results show that the Cu in CoPt films plays an important role in promoting the ordering parameter S and reducing the ordering temperature of CoPt films. A nearly perfect （001） texture was obtained in a CoPt film doped with 15.3 vol.% Cu. Besides, the preferred orientation of the CoPt film can be changed by annealing temperature. The perpendicular growth of the CoPt film is favored at a high annealing temperature.

Optimizing thermoelectric properties of BiSe through Cu additive enhanced effective mass and phonon scattering

Known as a weak topological insulator(TI),BiSe structurally exhibits alternating stacks of quantum spin Hall bilayer("Bi_(2)")and three-dimensional TI layer("Bi_(2)Se_(3)").The low lattice thermal conductivity of BiSe due to the presence of Bi2 bilayers promises potentially good thermoelectric performance.Herein,the thermoelectric properties of nominal Bi_(1-x)Cu_(x)Se samples were studied as the functions of the content of Cu additive and temperature.It is found that Cu additives in BiSe(1)profoundly affect the texture of densified polycrystalline samples by inclining the crystallographic c-axis parallel toward the pressure direction in the densification process,(2)increase considerably the effective mass and thus the Seebeck coefficient,and(3)yield point defects and Cu-Se secondary phases that effectively scatter heat-carrying phonons.As a result,the optimized electrical and thermal properties yield a thermoelectric figure of merit of zT~0.29 in Bi_(1-x)Cu_(x)Se(x=0.03)sample at 467 K in parallel to the pressure direction and a zT~0.20 at 468 K in the perpendicular direction.

Reducing the ordering temperature of FePt nanoparticles by Cu additive and alternate reduction method

(FePt)85Cu15 nanoparticles were successfully prepared by alternate reduction of metal salts in aqueous medium.Detailed investigations on the correlation between the magnetic and structural properties of these nanoparticles are presented as a function of annealing temperature.Both the X-ray diffraction patterns and the magnetic hysteresis loop measurements show the existence of L10-FePt phase at a relative low annealing temperature.It is proved that the Cu additive and alternate reduction are very effective methods in reducing the ordering temperature of FePt nanoparticles.

The Effect and Mechanism of Nano-Cu Lubricating Additives on the Electroless Deposited Ni-W-P Coating

The coating and deposition process with excellent anti wear and suitable for industrial application were developed, and the optimum bath composition and process were obtained by studying the influence of the bath composition, temperature and pH value on the deposition rate and the plating solution stability. Moreover, the tribological properties of nano-Cu lubricating additives and electroless deposited Ni-W-P coating as well as their synergistic effect are researched using ring-block abrasion testing machine and energy dispersive spectrometer. Research results show that Ni-W-P alloy coating and nano-Cu lubricating additive have excellent synergistic effect, e g, the wear resistance of Ni-W-P alloy coating （with heat treatment and the oil with nano-Cu additives） has increased hundreds times than 45 steel as the metal substrate with the basic oil, and zero wear is achieved, which breaks through the bottleneck of previous separate research of the above-mentioned two aspects.

Effects of Cu and Co additions on the crystallization and magnetic properties of FeNbB alloy

The nanocrystalline-forming element Cu and magnetic element Co are commonly used as additive elements to tune the structure and improve the properties of alloys.In this study,four kinds of amorphous alloys,Fe_(72)Nb_(12)B_(16),Fe_(72)Nb_(12)B_(15)Cu_(1),Fe_(36)Co_(36)Nb_(12)B_(16),and Fe_(36)Co_(36)Nb_(12)B_(15)Cu_(1),were prepared by melt-spinning and annealed at various temperatures to investigate the effects of Cu and Co additions,individually and in combination,on the crystallization and magnetic properties of Fe_(72)Nb_(12)B_(16)alloy.The four kinds of alloys exhibited different crystallization behaviors with different primary crystallization phases observed.For the Fe_(72)Nb_(12)B_(16)alloy,only theα-Mn-type metastable phase formed after annealing.The addition of 1 at.%Cu and 36 at.%Co led to the observation of theα-Mn-type andβ-Mn-type metastable phases,respectively,and a reduction in the crystallization volume fraction in the metastable phase.The Fe_(36)Co_(36)Nb_(12)B_(15)Cu_(1)alloy only exhibitedα-Fe(Co)phase as a primary phase,and the addition of both Cu and Co completely inhibited the precipitation of the metastable phase.Cu clusters were found in energy dispersive spectroscopy elemental maps.Compared with other alloys,Fe_(36)Co_(36)Nb_(12)B_(15)Cu_(1)alloy with both Cu and Co exhibited a lower coercivity(Hc)below 973 K.

Effects of Cu addition on microstructure and mechanical properties of as-cast magnesium alloy ZK60

The effects of Cu addition on the microstructure and mechanical properties of the as-cast magnesium alloy ZK60 were investigated with optical microscope, SEM, TEM, XRD, EPMA and tensile tester. The mechanism by which the mechanical properties are affected by Cu addition was discussed. The results show that Cu can effectively eliminate the intragranular solute segregations in the alloy, and the grain size of the alloy is decreased considerably with increasing the Cu amount. A ternary eutectic phase MgZnCu with a face-centered cubic structure is identified in the Cu-bearing alloys, which predominantly distributes at the grain boundary and acts as the nucleation sites of microcracks during the plastic deformation process. It is also found that the tensile properties of the alloy firstly increase by the trace addition of 0.5%-1%Cu and then decrease by a further addition up to 2.0%.

Hot deformation behavior and processing maps of Mg-Zn-Cu-Zr magnesium alloy

The deformation behaviors of a new quaternary Mg-6Zn-1.5Cu-0.5Zr alloy at temperatures of 523-673 K and strain rates of 0.001-1 s-1 were studied by compressive tests using a Gleeble 3800 thermal-simulator.The results show that the flow stress increases as the deformation temperature decreases or as the strain rate increases.A strain-dependent constitutive equation and a feed-forward back-propagation artificial neural network were used to predict flow stress,which showed good agreement with experimental data.The processing map suggests that the domains of 643-673 K and 0.001-0.01 s-1 are corresponded to optimum conditions for hot working of the T4-treated Mg-6Zn-1.5Cu-0.5Zr alloy.

Effect of Cu doping and annealing treatment on the microstructure and mag-netic properties of nanocrystalline single-phase Nd-Fe-B alloys

The effects of Cu addition and annealing treatment on the magnetic properties and microstructure of Ndl2.3Fe81.7-xCuxB6 （x=0-1.2） ribbons melt-spun and annealed were systematically investigated by the methods of vibrating sample magnetometer （VSM）, X-ray diffraction （XRD）, and transmission electron microscopy （TEM）. Optimum magnetic properties were achieved by annealing melt-spun Nd12.3Fe81.5Cu0.2B6 ribbons at 550℃ for 15 min, which only contained Nd2Fe14B phase. The remanence, coercive force, and maximum energy product increase by 18.4%, 36.2%, and 49% respectively compared with those of Cu-free samples. The sig- nificant improvement in magnetic properties originates from the freer grains of the samples by introducing Cu, which leads to the stronger exchange-coupling between neighboring grains.

Microstructure Characteristics,Texture Evolution and Mechanical Properties of Al-Mg-Si-Mn-xCu Alloys via Extrusion and Heat Treatment

In this work,the impact of extrusion and post-extrusion heat treatment(T6)on the microstructure and mechanical properties of the Al-1.2Mg-0.8Si-0.5Mn alloy with different Cu contents(0,0.6,1.3 and 2.0 wt%)was studied.Microstructure characterization showed that all extruded alloys exhibited elongated grain structure with an average grain size of~4.8μm.The dominant texture components were deformation texture(A*,Copper and P texture),while the proportion of random texture initially increased and then decreased with increasing Cu content.After T6 treatment,the grain size of the four alloys increased significantly,but the growth trend decreased with increasing Cu content,and the textures transformed into recrystallized textures(Cube,A and Goss texture).Tensile testing revealed that the designed T6 alloys with 2.0%Cu content exhibited an excellent strength-ductility balance,i.e.,a yield strength of 342.9 MPa,an ultimate tensile strength of 424.8 MPa and an elongation of 15.9%.The enhanced strength was mainly attributed to fine grain strengthening,solid solution strengthening and aging strengthening mechanisms.The superior ductility was due to the pinning effect of fine precipitates and high dislocation accommodation capacity caused by heat treatment.

Effect of Cu on Martensite Transformation of CoCrMo alloy for biomedical application

The martensite transformation of Co-29Cr-6Mo-xCu(Co-xCu,x=0,1.5,2,4,wt%)alloys was investigated in order to explore ductile Co-based alloy without Ni for biomedical application.The effect of Cu on martensite transformation of Co-29 Cr-6 Mo alloy was investigated using scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-Ray diffraction(XRD)and electron backscatter diffraction(EBSD)analysis.EBSD results revealed that the fraction ofγ-phase was increasing with increasing of copper content.In detail,the fraction ofγ-phase of aged Co-1.5 Cu alloy was 4.72%and noγ-phase was found in aged Co-0Cu alloy.Furthermore,the fraction ofγ-phase of aged Co-2Cu alloy and Co-4Cu alloy was 51.68%and 46.17%,respectively.This demonstrated that the minimum Cu content which could inhibit martensite transformation in this alloy system was 2 wt%.Calculated phase diagram revealed that increasing the copper content of this alloy system could enlargeγ-phase zone,which means Cu could inhibit the formation ofγ-phase and consequently stabilizeγ-phase.Randomly distributed Cu-rich phase was identified in aged Co-4Cu alloy.The possible reason for the inhibition of martensite transformation by Cu addition is that alloying with Cu atom might decrease charge accumulations and increase atomic bonds,which increase the stacking fault energy ultimately.

Preliminary study of microstructure, mechanical properties and corrosion resistance of antibacterial Ti-15Zr-xCu alloy for dental application

Ti-15 Zr-xCu(3≤x≤7,wt.%) novel antibacterial and antibiofilm alloys with competitive mechanical properties,biological responses and corrosion resistance were designed and fabricated.Annealing heat treatment on Ti-15 Zr-7 Cu(TZC-7 A),after holding for 2 h at slightly above their beta transus temperature(BTT) ensured their tensile strength(UTS),yield strength(YS) and hardness(HRV) were improved by31.2%,20% and 12.3% respectively compared to the control without Cu,Ti-15 Zr(T-15 ZA).Although the3 wt.% Cu alloy displayed the highest elongation(26%),the TZC-7 A alloy also possessed a good ductility.Presence of evenly dispersed Ti2 Cu and Zr2 Cu Cu-rich intermetallic phases formed as interwoven and alternating lamellae within the α+β matrix as a result of Cu addition,as revealed by X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).These greatly contributed to their strengthening and bactericidal properties.Over 98% antibacterial effect against E.coli and S.aureus have been imparted,coupled with excellent biofilm inhibition.Potentiodynamic polarization curves showed that the TZC-7 A alloy possessed higher corrosion resistance than commercially pure titanium,cp-Ti;contact angle test revealed enhanced hydrophilicity;while confocal laser scanning microscopy(CLSM) and cell counting kit(CCK-8) assays also displayed drastically lowered bacterial adhesion rate with comparatively no cytotoxicity.Cell attachment on all alloys was similar but the best spread was obtained on TZC-7 A after 24 h.The developed alloy has good potential as an antibacterial implant material with combination of optimized properties.

Effect of Cu Addition in Pipeline Steels on Microstructure,Mechanical Properties and Microbiologically Influenced Corrosion

In the present study, Cu-modified pipeline steels were fabricated to mitigate MIC by the antimicrobial ability of Cu element. The microstructure, mechanical properties and the antimircobial performance of the Cu-modified steel were systematically investigated. The Cu-modified steels showed good antimicrobial performance with remarkable strength enhancement by nanoscale Cu-rich precipitates and good impact toughness without changing the original base microstructures after the optimal aging treatment of 500 °C/1 h.

Cu(Ⅱ)-catalyzed domino reaction of 2-halobenzamide and arylmethanamine to construct 2-aryl quinazolinone

A novel method for achieving a copper（II）-catalyzed domino reaction for the construction of 2-aryl quinazolinones,without the addition of any ligand and additive,has been developed.The domino reaction achieved N-（a-substituted）benzylation,benzylic C–H amidation,and C–C（or C–H） bond cleavage.

On the Microstructural Strengthening and Toughening of Heat-Affected Zone in a Low-Carbon High-Strength Cu-Bearing Steel

In this article,the influence of simulated thermal cycles for the heat-aff ected zone(HAZ)on the microstructural evolution and mechanical properties in a low-carbon high-strength Cu-bearing steel was investigated by microstructural characterization and mechanical tests.The results showed that the microstructure of the coarse-grained heat-aff ected zone(CGHAZ)and the fine-grained heat-aff ected zone(FGHAZ)was mainly comprised of lath martensite,and a mixed microstructure consisting of intercritical ferrite,tempered martensite and retained austenite occurred in the intercritically heat-aff ected zone(ICHAZ)and the subcritically heat-aff ected zone(SCHAZ).Also,8–11%retained austenite and more or less Cu precipitates were observed in the simulated HAZs except for CGHAZ.Charpy impact test indicated that the optimum toughness was obtained in FGHAZ,which was not only associated with grain refinement,but also correlated with deformation-induced transformation of the retained austenite,variant confi guration as interleaved type and a relatively weak variant selection.The toughness of ICHAZ and SCHAZ exhibited a slight downtrend due to the presence of Cu precipitates.The CGHAZ has the lowest toughness in the simulated HAZs,which was attributed to grain coarsening and heavy variant selection.In addition,the contribution of Cu precipitates to yield strength in simulated HAZs was estimated based on Russell–Brown model.It demonstrated an inverse variation trend to toughness.

Microstructural Evolution of Co_(35)Cr_(25)Fe_(30)Ni_(10) TRIP Complex Concentrated Alloy with the Addition of Minor Cu and Its Effect on Mechanical Properties

The influences of minor Cu addition(2 and 4 at.%)on the microstructural evolution and room-temperature mechanical property of metastable Co_(35)Cr_(25)Fe_(30)Ni_(10)are systemically investigated in the present study.The results indicate that the thermally induced hexagonal close-packed(HCP)phase is absent when Cu was added,due to the increase in stacking fault energy(SFE).The 2%-Cu-added alloys showed the largest total elongation of 69%among the three alloys.With the addition of Cu content reaching 4 at.%,heterogeneous grain structures composed of coarse grains(~9μm)and fine grains(~4μm)and Cu-rich precipitates near the grain boundary are observed,showing the highest yield strength.Additionally,the segregation state of Cu was quantitatively characterized by electron probe microanalysis(EPMA).And effects of Cu addition on microstructures and tensile properties of(Co_(35)Cr_(25)Fe_(30)Ni_(10))_(100-x) Cu _(x) are also discussed.The findings are beneficial to comprehensively understand the Cu-containing complex concentrated alloys.

Osteogenesis stimulation by copper-containing 316L stainless steel via activation of akt cell signaling pathway and Runx2 upregulation

As a metallic orthopedic implant,316L stainless steel(316L SS)is used extensively for its good resistance to corrosion and mechanical properties.However,it takes a long time to achieve osseointegration between 316L SS and adjacent tissues due to its bio-inert characteristic.Hence,the aim is to improve the bio-adaption of 316L SS.A good approach is to add elements to materials to improve their osteogenic capabilities by the appropriate release of ions.Hence copper-containing 316L stainless steel(316L-Cu SS)was investigated in this work,where Cu is an essential trace element that can stimulates osteogenesis.It was found that 316L-Cu SS was bio-safe and did not affect the proliferation of co-cultured osteoblasts in comparison with 316L SS.It increased cell apoptosis on day 1 but inhibited it on day 3,which cooperates with new bone formation processes.Osteoblasts extend themselves more quickly and in a better manner on the surface of 316L-Cu SS,wheneven more pseudopodia are present.Furthermore,the gene expression of alkaline phosphatase,collagen I and runt-related transcription factor 2(Runx2)in osteoblasts cultured with 316L-Cu SS was significantly enhanced.Runx2 protein expression increased,and osteogenesis was stimulated by 316L-Cu SS via an Akt cell signaling pathway.In conclusion,316L-Cu SS stimulates osteogenesis through activation of the Akt cell signaling pathway and the upregulation of Runx2.Thus,316L-Cu SS is a promising material that may be used in surgical implants to stimulate osteogenesis.