Deformation behavior and microstructural evolution during the semi-solid compression of Al–4Cu–Mg alloy

The effects of the process parameters, including deformation temperature and strain rate, on the deformation behavior and microstructure of an Al–4Cu–Mg alloy, have been investigated through isothermal compression. Experiments were conducted at deformation temperatures of 540 °C, 560 °C, and 580 °C, strain rates of 1 s⁻¹, 1×10⁻¹ s⁻¹, 1×10⁻² s⁻¹, and 1×10⁻³ s⁻¹, and height reductions of 20%, 40%, and 60%. The experimental results show that deformation temperature and strain rate have significant effect on the peak flow stress. The flow stress decreases with an increase of deformation temperature and/or a decrease of the strain rate. Above a critical value of the deformation temperature, the flow stress quickly reaches a steady value. Experimental materials A and B have equiaxed and irregular grains, respectively, prior to deformation. The microstructures vary with the process parameters in the semi-solid state. For material B, the irregular grains transform to equiaxed grains in the process of semi-solid deformation, which improves the deformation behavior.     

Ultra-high-speed deformation by impact of a projectile flying at speeds on the order of km s

An apparatus was developed to facilitate application of an electro-thermo-chemical accelerator to high-speed deformation experiments. The apparatus is designed on the principle of sequential collision of elastic bodies. Speeds ranging from 600 to 780 m s⁻¹ were achieved, and estimated strain rate of deformation is 10⁷ s⁻¹. The newly developed apparatus can be applied to various types of accelerators for attaining deformation speeds as high as several km s⁻¹. Transmission electron microscopy of aluminum deformed at high speed by use of the apparatus revealed the formation of very small stacking fault tetrahedra (SFTs). This observation is quite new for aluminum; previously, SFTs had not been observed in aluminum, although deformation had been carried out at strain rates lower than 10⁶ s⁻¹. Use of the apparatus promises to provide new insight into high-speed deformation.     

Light emitting devices from organic charge transfer adduct thin films

For the first time, thin film devices of charge transfer adducts of tetrathiafulvalene (TTF) have been fabricated. A luminance of 5 cd m⁻² has been achieved for a device structure ITO/poly(aniline)/TTF(NO₃)_0.55/Al whose EL spectrum has a broad peak at 645 nm. The devices were fabricated by spin coating from solutions of the adducts. A luminous efficiency of 5×10⁻⁴ lm W⁻¹ has been obtained for these devices which is comparable to that of ITO/poly(aniline)/Alq₃/Al (5.2×10⁻⁴ lm W⁻¹) under same fabrication conditions. The single layer, mixed layer and double layer devices fabricated in this study fit the space charge limited model. Devices fabricated from the adduct [TTF–Alq₃] emit white light (40 cd m⁻²) with a luminous efficiency of 6.6×10⁻⁴ lm W⁻¹. The colour of light emitted appears to depend on the effective oxidation state of TTF in the adducts.     

Cross-linked quaternary chitosan as an adsorbent for the removal of the reactive dye from aqueous solutions

Adsorption of reactive orange 16 by quaternary chitosan salt (QCS) was used as a model to demonstrate the removal of reactive dyes from textile effluents. The polymer was characterized by infrared (IR), energy dispersive X-ray spectrometry (EDXS) analyses and amount of quaternary ammonium groups. The adsorption experiments were conducted at different pH values and initial dye concentrations. Adsorption was shown to be independent of solution pH. Three kinetic adsorption models were tested: pseudo-first-order, pseudo-second-order and intraparticle diffusion. The experimental data best fitted the pseudo-second-order model, which provided a constant velocity, k₂, of 9.18 × 10⁻⁴ g mg⁻¹ min⁻¹ for a 500 mg L⁻¹ solution and a value of k₂, of 2.70 × 10⁻⁵ g mg⁻¹ min⁻¹ for a 1000 mg L⁻¹ solution. The adsorption rate was dependent on dye concentration at the surface of the adsorbent for each time period and on the amount of dye adsorbed. The Langmuir isotherm model provided the best fit to the equilibrium data in the concentration range investigated and from the isotherm linear equation, the maximum adsorption capacity determined was 1060 mg of reactive dye per gram of adsorbent, corresponding to 75% occupation of the adsorption sites. The results obtained demonstrate that the adsorbent material could be utilized to remove dyes from textile effluents independent of the pH of the aqueous medium.     

Dynamical behaviour and microstructural evolution of a nitrogen-alloyed austenitic stainless steel

The aim of this work is to study the mechanical properties of a nitrogen austenitic stainless steel (Uranus B66) and their relation to its microstructural evolution. Quasi-static (10⁻³ s⁻¹) and quasi-dynamic (1 s⁻¹) compression tests have been carried out with a universal servo-hydraulic testing machine. Dynamic (>10³ s⁻¹) compression tests have been performed on a classical split-Hopkinson bar apparatus. These tests, which cover a wide range of plastic strain, show that the material has a high-strain hardening rate, a good ductility and a great strain rate sensitivity. The temperature sensitivity has been determined over a large range, going from 77 K to 673 K. Transmission electron microscopy (TEM) observations have been conducted in order to correlate the microstructure to the mechanical behaviour. Uranus B66 undergoes basically the same structure evolution during both quasi-static and dynamic compression tests. The plastic deformation is governed initially by planar gliding, followed by mechanical twinning when the dislocation density is saturated.     

Semiconducting and structural properties of CrSi2 A-type epitaxial films on Si(111)

Chromium disilicide (CrSi₂) films 1 000 Å thick have been prepared by molecular beam epitaxy on CrSi₂ templates grown on Si(111) substrate. The effect of the substrate temperature on the structural, electrical and optical properties of CrSi₂ films has been studied by transmission and scanning electron microscopies, optical microscopy, electrical resistivity and Hall effect measurements and infrared optical spectrometry. The optimal temperature for the formation of the epitaxial A-type CrSi₂ film have been found to be about 750°C. The electrical measurement have shown that the epitaxial A-type CrSi₂ film is p-type semiconductor having a hole concentration of 1 × 10¹⁷cm⁻³ and Hall mobility of 2 980 cm² V⁻¹ s⁻¹ at room temperature. Optical absorption coefficient data have indicated a minimum, direct energy gap of 0.34 eV. The temperature dependence of the Hall mobility (μ) in the temperature range of T = 180–500 K can be expressed as μ = 7.8 × 10¹⁰T⁻³cm²V⁻¹s⁻¹.     

Pressure-shear impact and the dynamic viscoplastic response of metals

Pressure-shear plate impact experiments are used to investigate the viscoplastic response of metals at shear strain rates ranging from 10⁵ s⁻¹ to 10⁷ s⁻¹. Flat specimens with thicknesses between 300 μm and 3 μm are sandwiched between two hard, parallel plates that are inclined relative to their direction of approach. Nominal stresses and strains in the specimens are determined from elastic wave profiles monitored at the rear surface of one of the hard plates. Results are reviewed for two fcc metals: commercially pure aluminum and an aluminum alloy. New results are presented for bcc high purity iron, a high strength steel alloy and vapor deposited aluminum. For commercially pure aluminum the flow stress increases strongly with strain rate as strain rate increases from 10⁴ s⁻¹ to 10⁵ s⁻¹. At strain rates above 10⁵ s⁻¹ the flow stress, based on results for thin vapor-deposited aluminum specimens, increases strongly, but less than linearly, with increasing strain rate until it saturates at strain rates between 10⁶ s⁻¹ and 10⁷ s⁻¹. Preliminary results for high purity alpha-iron indicate that the flow stress increases smoothly over eleven decades of strain rate, and faster than logarithmically for strain rates from 10² s⁻¹ to greater than 10⁶ s⁻¹. In contrast, for a high strength steel alloy the flow stress depends only weakly on the strain rate, even at strain rates at high as 10⁵ s⁻¹. Such contrasting behavior is attributed to differences in the relative importance of viscous glide and thermal activation as rate controlling mechanisms for dislocation motion in the various metals. Numerical studies indicate that experiments performed at the highest strain rates on the thinnest specimens are not adiabatic, thus requiring a full thermal-mechanical analysis in order to interpret the data.     

Effect of Al2O3 particles on mechanical properties of directionally solidified intermetallic Ti–46Al–2W–0.5Si alloy

The effect of Al₂O₃ particles on microhardness and room-temperature compression properties of directionally solidified (DS) intermetallic Ti–46Al–2W–0.5Si (at.%) alloy was studied. The ingots with various volume fractions of Al₂O₃ particles and mean ₂–₂ interlamellar spacings were prepared by directional solidification at constant growth rates ranging from 2.78×10⁻⁶ to 1.18×10⁻⁴ ms⁻¹ in alumina moulds. The ingots with constant volume fraction of Al₂O₃ particles and various mean interlamellar spacings were prepared by directional solidification at a growth rate of 1.18×10⁻⁴ ms⁻¹ and subsequent solution annealing followed by cooling at constant rates varying between 0.078 and 1.889 K s⁻¹. The mean ₂–₂ interlamellar spacing λ for both DS and heat-treated (HT) ingots decreased with increasing cooling rate according to the relationship λ∝ ^−0.46. In DS ingots, microhardness, ultimate compression strength, yield strength and plastic deformation to fracture increased with increasing cooling rate. In HT ingots, microhardness and yield strength increased and ultimate compression strength and plastic deformation to fracture decreased with increasing cooling rate. The yield stress increased with decreasing interlamellar spacing and increasing volume fraction of Al₂O₃ particles. A linear relationship between the Vickers microhardness and yield stress was found for both DS and HT ingots. A simple model including the effect of interlamellar spacing and increasing volume fraction of Al₂O₃ particles was proposed for the prediction of the yield stress.     

Adhesion, microstructure and composition of thermally evaporated aluminium thin layers on polyethylene terephthalate films

Industrial polyethylene terephthalate (PET) films have been metallized by aluminium evaporation in two different sets of experimental conditions. In the first set, aluminium layers of 100 nm thickness were deposited at a constant deposition rate (10 Å s⁻¹) for different residual pressures varying from 1 Pa to 10⁻⁴ Pa and, in the second set, the residual pressure was kept constant (2.6 × 10⁻³ Pa), while the deposition rate was varied from 5 Å s⁻¹ to 40 Å s⁻¹.

The adherence between the aluminium layers and the PET film was measured by means of scratch and peel tests. The critical load and the peel strength exhibit a maximum at about 10⁻² Pa when the deposition rate is kept constant.

The microstructure of the aluminium layers, mainly the mean grain size, was studied by transmission electron microscopy (TEM), while secondary ion mass spectrometry (SIMS) depth profiles through the aluminium layers were performed in order to provide the chemical information, mainly aluminium layer oxidation. Concerning the TEM results, the grain size increases when the residual pressure is decreased and also when the deposition rate is increased. The SIMS depth profiles show different levels for aluminium oxidation at the surface, in the bulk of the layers and at the interface, all increasing for high residual gas pressure and for low deposition rates.

From these results, it appears that the oxygen content at the Al---PET interface plays a critical role in the microstructure owing to its influence on the nucleation and on the growth of the aluminium layers. It also influences the adhesion between aluminium and PET for which an optimum oxygen amount seems to be required.     

Synthesis of some ferromagnetic composite resins and their metal removal characteristics in aqueous solutions

In this study, a procedure for synthesis of new organic-inorganic magnetic composite resins was established. The procedure was based upon immobilization of magnetite (Mag) as a ferromagnetic material within the polymer poly(acrylic acid acrylonitrile) P(AA-AN) and the ion exchange resin (Amberlite IR120). The produced magnetic resins, IR120-PAN-Mag (R1) and P(AA-AN)-Mag (R2) were assessed as sorbents for Cr(VI). Various factors influencing the sorption of Cr(VI), e.g., pH, equilibrium time, initial concentration and temperature were studied. The sorption process was very fast initially and maximum sorption was achieved within 3 h and pH 5.1. The kinetic of the system has been evaluated with pseudo first order model, second order model, Elovich model, intra-particle diffusion model and liquid film diffusion model. Chromium interaction with composite particles followed second-order kinetics with a correlation coefficient extremely high and closer to unity and rate constant (k_s) has the values 1.68 × 10⁻⁴ and 1.9 × 10⁻⁴ g (mg⁻¹ min⁻¹) for R1 and R2, respectively. The values of equilibrium sorption capacity (q_e) are consistent with the modeled data and attain the range 893–951 mg g⁻¹. Kinetically, both pore diffusion and film diffusion are participating in ruling the diffusion of Cr(VI) ions. The sorption data gave good fits with Temkin and Flory–Huggins isotherm models. The isotherm parameters related to the heat of sorption are in the range 8–16 kJ mol⁻¹ which is the range of bonding energy for ion exchange interactions and so suggest an ion exchange mechanism for removal of Cr(VI) by the composite sorbents. The adsorption process was exothermic with ΔH in the range of −73 to −97 kJ mol⁻¹. The negative values of Gibbs free energy confirm the feasibility and the spontaneous nature of Cr(VI) removal with these novel composites.     

Enhanced fluoride sorption by mechanochemically activated kaolinites

This study investigated the surface modification of photocatalyst and photodecomposition of formaldehyde from indoor pollution source. This study explored the feasibility of the application of the ultraviolet light emitting diode (UVLED) instead of the traditional ultraviolet (UV) lamp to treat the formaldehyde. The photocatalytic decomposition of formaldehyde at various initial concentrations was elucidated according to the Langmuir–Hinshelwood model. The reaction rate constant (k) and adsorption equilibrium constant (K_L) over 0.334 g silver titanium oxide photocatalyst (Ag/TiO₂) coated on glass sticks with 254 nm ultraviolet lamp (UVC), 365 nm ultraviolet lamp (UVA), and UVLED are 650 ppmv min⁻¹ and 2 × 10⁻⁴ ppmv⁻¹, 500 ppmv min⁻¹ and 1.04 × 10⁻⁴ ppmv⁻¹, and 600 ppmv min⁻¹ and 2.52 × 10⁻⁵ ppmv⁻¹, respectively. A comparison of the simulation results with the experimental data was also made, indicating good agreement. The magnitudes of energy effectiveness (E_e) are in the order of UVLED (0.6942 mg kW⁻¹ h⁻¹) > UVA (0.007 mg kW⁻¹ h⁻¹) > UVC (0.0053 mg kW⁻¹ h⁻¹). The E_e of UVLED is 131 times larger than that of UVC. The UVLED can save a lot of energy in comparison with the traditional UV lamps. Thus, this study showed the feasible and potential use of UVLED in photocatalysis.     

Dislocation structures introduced by high-speed deformation in bcc metals

Systematic experiments were carried out over a wide range of strain rate, 10⁰–10⁶ s⁻¹, so as to reveal the deformation mode in bcc crystals, especially at high strain rate. Dislocation structure showed heterogeneous distribution at low strain rates in all three bcc metals examined. At higher strain rates exceeding 10³ s⁻¹, distribution of dislocations was random, and the formation of small dislocation loops was observed in V and Nb. In Mo, small dislocation loops were not formed by deformation, even at high strain rates. However, post-deformation annealing of an Mo specimen that had been deformed by 20% at 5×10⁵ s⁻¹ produced dislocation loops. The inside–outside contrast method identified these loops to be of vacancy type. These results reveal that in Mo vacancy clusters are not formed directly from the interaction of dislocations, but by the aggregation of vacancies. In V and Nb, the same formation process is believed to occur at high strain rates. These results suggest that the different mode of plastic deformation at high strain rates accompanied by production of vacancies also occurred in bcc metals.     

Up-conversion dynamics in GdAlO3:Er single crystal fibre

Green fluorescence has been obtained under continuous laser excitation in the 780–860 nm range in GdAlO₃:Er³⁺. With the help of the Judd-Ofelt treatment we built a model based on population rate equations to describe its time evolution. We found the intensity parameters to be Ω₂ = 2.045 × 10⁻²⁰ cm², Ω₄ = 1.356 × 10⁻²⁰ cm² Ω₆ = 1. 125 × 10⁻²⁰ cm². Even if a two-photon absorption and a looping mechanism are necessary to well describe the dynamics, the main process responsible for up-conversion is energy transfer between erbium ions.     

Anoxic treatment of trifluralin-contaminated soil

Amending anoxic soils with stoichiometric amounts of sodium acetate led to the complete transformation of trifluralin within the 45 day treatment period. Under these conditions, a maximum trifluralin transformation rate of 4.9 mg kg⁻¹ of soil per day was estimated, which corresponded to a chemical half life of 11.9 days. Regression analyses indicated that the zero order rate model provided the best fit to the experimental data, suggesting that the trifluralin transformation rate is independent of concentration during acetate addition. Using radiolabeled trifluralin, it was determined that the principal contaminant transformation mechanisms were degradation and bound residue formation (i.e., irreversible adsorption). Volatilization and mineralization of trifluralin were found to be negligible over the 45 day treatment period. Using poisoned controls, it was determined that trifluralin transformation under acetate-amended conditions was biologically mediated.

Amending trifluralin contaminated soils with stoichiometric amounts of iron sulfide resulted in complete trifluralin transformation within 24 hours of treatment. A maximum trifluralin transformation rate of 380 mg kg⁻¹ of soil per day was estimated for this system, which corresponded to a chemical half life of 4.4 h. The rates of trifluralin transformation followed the first-order kinetic model during iron sulfide addition. Using radiolabeled trifluralin, it was found that chemical degradation was the principal removal mechanism. Neither volatilization nor mineralization was found to be a significant contaminant removal mechanism during iron sulfide treatment. Poisoned controls indicated that trifluralin transformation was mediated primarily by an abiotic chemical reaction mechanism. Additional study is required to clarify the rate limiting steps so that full scale soil treatment systems may be properly designed.     

Defect structure of gold introduced by high-speed deformation

The effect of deformation speed on defect structures introduced into bulk gold specimens at 298 K has been investigated systematically over a wide range of strain rate from ′=10⁻² to 10⁶ s⁻¹. As strain rate increased, dislocation structure changed from heterogeneous distribution, so-called cell structure, to random distribution. Also, stacking fault tetrahedra (SFTs) were produced at anomalously high density by deformation at high strain rate. The anomalous production of SFTs observed at high strain rate is consistent with the characteristic microstructure induced by dislocation-free plastic deformation, which has been recently reported in deformation of gold thin foils. Thus, the results of the present study indicate that high-speed deformation induces an abnormal mechanism of plastic deformation, which falls beyond the scope of dislocation theory. Numerical analysis of dislocation structure and SFTs revealed that the transition point of variation of deformation mode is around the strain rate of 10³ s⁻¹.     

Crystallinity properties of parylene-n affecting its use as an ILD in submicron integrated circuit technology

Parylene-n (Poly-p-xylylene) (PA-n) [1–3] has a long history of use as a moisture barrier for printed circuit boards and hybrids. This paper evaluates this compound as a candidate vapor-depositable polymer interlayer dielectric for submicron integrated circuit technology due to its low dielectric constant, good step coverage, and high etch selectivity. To apply PA-n on high-density very large scale integrated circuits, its properties, such as deposition rate, deposition yield, and Crystallinity, are investigated as a function of deposition pressure and annealing temperature. The deposition rate was found in the range of 2.66 Pa to 13.3 Pa to be a linearly increasing function of pressure. Good-quality films were obtained when pressure was controlled below 10.64 Pa. Cloudy films, however, were found at 13.3 Pa. The deposition rate could be as high as 3.33 × 10⁻¹⁰ m s⁻¹ when deposited at 10.64 Pa. The plot of PA-n yield vs. pressure showed a constant plateau of 1 × 10⁻⁴ m kg⁻¹ from 2.66 Pa to 10.64 Pa. The optimum deposition rate was hence obtained at 10.64 Pa without compromising the deposition yield. The crystallinity-associated properties examined were hardness, dielectric constant, and water permeability. A lower deposition pressure was observed to produce higher Crystallinity that could be further enhanced by thermal annealing. A 5 × 10⁻⁸ m hard surface layer was detected with hardness 3.5 GPa, that was 3˜7 times larger than that of bulk hardness which was 0.4˜0.7 GPa. The bulk hardness was found to increase as Crystallinity increased. The dielectric constant tended to increase when the deposition pressure decreased. Furthermore, the dielectric constant was nearly constant when the polymer was heated up to temperatures as high as 698 K. This behavior, together with the formation of the hard layer and a higher Crystallinity, was believed to result from the improved film organization of the deposited films. The competition between the film build-up in the surface region and the monomer diffusion into the bulk region (penetration) was theorized to be responsible for the film organization. The water permeability, which was measured to be as low as 1.2 × 10⁻¹⁵ kg m⁻¹ s⁻¹ Pa⁻¹ and was found to increase as the deposition pressure was increased, further strengthened the film organization claim.     

Ordered Langmuir-Blodgett films of a substituted lutetium bisphthalocyanine

High-quality LB multilayers have been prepared from the Lu(III) sandwich complex of 2,3,9,10,16,17,23,24-octa (n-butoxy)phthalocyanine (LuPc₂(OBu)₁₆). Surface pressure-area isotherms were characterized and indicate that a stable monolayer is formed corresponding to an area per molecule of 2.4 nm² at 30 mN m⁻¹. The LB films were highly birefringent, and polarized spectra gave dichroic ratios of 3.3 for the 670 nm absorption band and between 0.5 and 2.8 for infrared absorptions. The results indicate that the phthalocyanine rings were highly oriented perpendicular to the dipping direction but somewhat tilted from the substrate normal. The order was shown to be absent when (i) unsubstituted LuPc₂ was used for LB films, or (ii) the horizontal lifting method of film deposition was used, or (iii) the surface pressure was increased to 50 mN m⁻¹, causing a molecular rearrangement. The ordering was improved at 100 °C and finally lost at 280 °C by annealing on a hot stage. The d.c. electrical conductivity of LB films of LuPc₂(OBu)₁₆ was low (σ ≈ 2 × 10⁻⁷ Ω⁻¹ m⁻¹), in contrast with unsubstituted LuPc₂ (σ ≈ 10⁻¹ Ω⁻¹ m⁻¹) and showed no evidence for anisotropy. The findings are in broad agreement with related studies and illustrate some of the many factors involved in improving the structure of phthalocyanine LB films for possible applications.     

Effects of reduction treatment on the photorefractive properties of Pb0.5Ba0.5Nb2O6

Lead barium niobate is a new photorefractive material of high interest for a variety of applications including holographic storage. Pb_0.5Ba_0.5Nb₂O₆ crystals have been grown by the Bridgman method, and the effects of heat treatments on their photorefractive properties were investigated using Ar ion laser at λ=514.5 nm. The color and absorption spectrum of the crystals varied depending on the oxygen partial pressure during heat treatment. The oxygen diffusivity was estimated to be in the order of 10⁻⁶ and 10⁻⁵ cm²/h at 425 and 550 °C, respectively. Reduction treatment at an oxygen pressure of 215 mTorr increased the effective density of photorefractive charges about three times from 8.0×10¹⁵ to 2.2×10¹⁶ cm⁻³ and made the charge transport more electron-dominant. As a result, the maximum gain coefficient improved from 5.5 to 13.8 cm⁻¹. A diffraction efficiency as high as 70% was achieved in a reduced crystal.     

Numerical and experimental analysis of superplastic-like uniaxial tensile necking of coarse-grained LY-12

In this work, numerical and experimental studies of superplastic-like uniaxial tensile behavior of coarse-grained LY-12 have been performed. Larger tensile elongation to fracture is observed and several necks are exhibited at 10⁻¹ and 10⁻⁴ s⁻¹ respectively although not very clearly. Chaboche viscoplastic constitutive equations are used and implemented in a finite element code to simulate the process of necks formation and development before fracture during uniaxial tension. The simulated characteristics of more than one necks along the specimens help to obtain large elongation, which is in agreement with experimental observations. Local strain rate distribution as the function of strain can explain how and when microscopic necks take place.     

Molecular dynamics study of the mechanical behavior of nickel nanowire: Strain rate effects

We present the analysis of uniaxial deformation of nickel nanowires using molecular dynamics simulations, and address the strain rate effects on mechanical responses and deformation behavior. The applied strain rate is ranging from 1 × 10⁸ s⁻¹ to 1.4 × 10¹¹ s⁻¹. The results show that two critical strain rates, i.e., 5 × 10⁹ s⁻¹ and 8 × 10¹⁰ s⁻¹, are observed to play a pivotal role in switching between plastic deformation modes. At strain rate below 5 × 10⁹ s⁻¹, Ni nanowire maintains its crystalline structure with neck occurring at the end of loading, and the plastic deformation is characterized by {1 1 1} slippages associated with Shockley partial dislocations and rearrangements of atoms close to necking region. At strain rate above 8 × 10¹⁰ s⁻¹, Ni nanowire transforms from a fcc crystal into a completely amorphous state once beyond the yield point, and hereafter it deforms uniformly without obvious necking until the end of simulation. For strain rate between 5 × 10⁹ s⁻¹ and 8 × 10¹⁰ s⁻¹, only part of the nanowire exhibits amorphous state after yielding while the other part remains crystalline state. Both the {1 1 1} slippages in ordered region and homogenous deformation in amorphous region contribute to the plastic deformation.