Effect of ternary addition and γ-irradiation on the characteristics of rapidly solidified Pb-base alloys

The properties of a series of rapidly solidified Pb-Sb 3 -Sn x alloys ( x =0-2.5 r wt.%) irradiated with n -rays were studied. Variations in the internal friction, Q m 1 , thermal diffusivity D th and dynamic Young's modulus Y were traced before and after irradiation by applying the resonance technique. Variations of specific heat C p were obtained from DTA thermograms. Structure parameters were obtained from the X-rays diffraction patterns. A marked change in the behaviour of the measured parameters was observed at 1.5 r wt.% Sn addition. Besides, irradiation induced defects increased the level of the measured hardening parameters.     

Effect of lead on microstructure and some physical properties of Sn–Zn–Cd alloy

The effect of lead on the structure, electrical resistivity, internal friction, elastic modulus and thermal properties of Sn₈₁Zn₉Cd₁₀ ternary alloys have been investigated using different experimental techniques with their analysis. In addition, properties of this alloy were compared with other Sn–Zn or Sn–Zn–Cd alloys and commercial solder alloys. It has a higher electrical resistivity, internal friction and lower elastic modulus when compared with Sn–Zn or Sn–Zn alloys with other additions such as Cd, Bi or In. The Sn₆₁Zn₉Cd₁₀Pb₂₀ alloy has a lower melting point, electrical resistivity and internal friction when compared with the commercial Pb–Sn solder alloy, but it has a similar elastic modulus.     

Effect of cooling speed on structure and properties of rapidly solidified Pb–25wt.% Sn alloy

The effect of cooling speed on structure, hardness, mechanical and electrical transport properties of rapidly solidified Pb–25wt.% Sn alloy have been investigated. A single roller melt spinning technique with linear speeds 15.7 and 31.7 m/s, was used for the preparation of specimens. The results showed that a lower cooling speed increased the precipitation of Sn in a Pb-matrix phase as compared with the higher cooling speed. This decomposition behavior decreased the electrical resistivity and increased the internal friction, thermal diffusivity and Vickers microhardness of the lower cooling speed as compared with those of the higher cooling speed.     

Radiation annealing of rapidly solidified Sn–6.7Sb–5.3Zn alloy by low-dose gamma ray

The radiation annealing of a rapidly solidified Sn–6.7Sb–5.3Zn (in atomic percent) melt-spun alloy was caused by low-dose gamma ray irradiation. This is observed from the increase in both the volume of unit cell and particle size of the Sn matrix, as revealed from X-ray diffraction analysis, and the decrease in the resistivity. The alloy was irradiated by gamma ray at doses 5, 10, 20, 40, 50, 60, 70, 80, and 100 Gy. The electrical resistivity was measured for the alloys subjected to these doses and it was found that the resistivity decreased by increasing the dose to a minimum value of 50 Gy and then increased by increasing the dose.     

Effect of copper on the structure–phase transformations and the properties of quasi-binary TiNi–TiCu alloys

The effect of copper alloying up to 25 at % on the structure–phase transformations and the physicomechanical properties of ternary alloys from the quasi-binary TiNi–TiCu section is studied by measuring the physicomechanical properties, transmission electron microscopy, scanning electron microscopy, electron diffraction, and X-ray diffraction (XRD). The data of temperature measurements of the electrical resistivity and the magnetic susceptibility and XRD data are used to plot a general diagram for the thermoelastic B2 ? B19', B2 ? B19 ? B19', and B2 ? B19 martensitic transformations, which occur in the alloys upon cooling as the copper content increases in the ranges 0–8, 8–15, and 15–25 at % Cu, respectively. The experimental results are compared to the well-known data, including differential scanning calorimetry data, obtained for these alloys. The changes in the mechanical properties and the microstructure of the alloys in the state of B19 or B19' martensite are discussed.     

Effect of Ge doping on the electrical properties of amorphous Zn–Sn–O thin films

We report the effect of germanium doping on the active layer of amorphous Zinc–Tin-Oxide (a-ZTO) thin film transistor (TFT). Amorphous thin film samples were prepared by RF magnetron sputtering using single targets composed of Zn₂Ge_0.05Sn_0.95O₄ and Zn₂SnO₄ with variable oxygen contents in the sputtering gases. In comparison with undoped, Ge-doped a-ZTO films exhibited five order of magnitude lower carrier density with a significantly higher Hall-mobility, which might be due to suppressed oxygen vacancies in the a-ZTO lattice since the Ge substituent for the Sn site has relatively higher oxygen affinity. Thus, the bulk and interface trap densities of Ge-doped a-ZTO film were decreased one order of magnitude to 7.047 × 10¹⁸ eV⁻¹cm⁻³ and 3.52 × 10¹¹ eV⁻¹cm⁻², respectively. A bottom-gate TFT with the Ge-doped a-ZTO active layer showed considerably improved performance with a reduced SS, positively shifted V_th, and two orders of magnitude increased I_on/I_off ratio, attributable to the doped Ge ions.     

Effect of vanadium neighbors on the hyperfine properties of iron–vanadium alloys

The electronic and magnetic structures of Fe–V alloys are calculated using the discrete-variational and full-potential linearized-augmented-plane wave methods. The derived hyperfine properties at Fe sites are studied against the number of Fe atoms in the neighbouring shells. As expected the magnetic hyperfine field depends strongly on the number of Fe atoms in the first and second shells of neighbours while its dependence on the variation of atoms in the third shell is weak. The calculated distribution of the magnetic hyperfine fields at the Fe sites, are compared to the experimental data of Krause et al. (Phys Rev B 61:6196–6204, 2000). The contact charge densities and the magnetic moments are also calculated. It was found that the contact charge density increases with increasing V contents and this leads to negative isomer shift on addition of V.     

Effect of Sn and Al additions on the microstructure and mechanical properties of amorphous Ti–Cu–Zr–Ni alloys

Amorphous Ti–Cu–Zr–Ni alloys with minor addition of Sn and Al were prepared by melt spinning technique.The effects of Sn and Al additions on the microstructures and mechanical properties of glassy ribbons were investigated.The amorphous state of ribbons was confirmed by x-ray diffraction and transmission electron microscopy,where those ribbons with Sn addition exhibited a fully amorphous state.The characteristic temperature indicates that Ti_(45)Cu_(35)Zr_(10)Ni_5Sn_5 alloy has a stronger glass-forming ability,as proven by differential scanning calorimetry.Ti_(45)Cu_(35)Zr_(10)Ni_5Al_5 alloy showed a better hardness of 9.23 GPa and elastic modulus of 127.15 GPa and good wear resistance.Ti_(45)Cu_(35)Zr_(10)Ni_5Sn_5 alloy displayed a pop-in event related to discrete plasticity according to nanoindentation.When the temperature is below 560 K,Ti_(45)Cu_(35)Zr_(10)Ni_5Sn_5 alloy mainly exhibits elasticity.When the temperature rises between 717 K and 743 K,it shows a significant increase in elasticity but decrease in viscoelasticity after the ribbon experiences the main relaxation at 717 K.When the temperature is above 743 K,the ribbon shows viscoplasticity.     

Effect of thermal cycling on structure and properties of Ni–Mn–In-based alloys

Technical Physics - The results of investigations of the structure and properties of ternary alloys Ni47–x Mn42 + x In11 (0 ≤ x ≤ 2) after thermal cycling are presented. It has...     

Surface tension modelling of liquid Cd–Sn–Zn alloys

The thermodynamic model in conjunction with Butler equation and the geometric models were used for the surface tension calculation of Cd–Sn–Zn liquid alloys. Good agreement was found between the experimental data for limiting binaries and model calculations performed with Butler model. In the case of ternary alloys, the surface tension variation with Cd content is better reproduced in the case of alloys lying on vertical sections defined by high Sn to Zn molar fraction ratio. The calculated surface tension is in relatively good agreement with the available experimental data. In addition, the surface segregation of liquid ternary Cd–Sn–Zn and constituent binaries has also been calculated.     

Effect of germanium addition on the physical properties of Se–Te glassy semiconductors

The effect of germanium addition on the physical properties, i.e. density, molar volume, compactness, number of lone-pair electrons, average coordination number, heat of atomization, mean bond energy, cohesive energy and glass-transition temperature, of (Se₈₀Te₂₀)_{100? x} Ge _x (x = 0, 2, 4, 6) bulk glassy alloys was investigated. The density of the glassy alloys is found to decrease with increasing Ge content. The molar volume and compactness of the structure of the glass were determined from the measured density. The mean bond energy is proportional to the glass-transition temperature. The cohesive energy of the samples has been calculated using a chemical bond approach and is correlated with an increase in the optical energy gap with increase in the Ge content. The heat of atomization was also calculated and correlated with the optical energy gap. The glass-transition temperature has been estimated using different methods and is found to increase with an increase of Ge content.     

Effect of nanoparticles on the magnetic properties of Mn–Zn soft ferrite

In this paper, the effect of nanostructures on the magnetic properties like the specific saturation magnetization (σ_S) and the coercivity (H_C) for Mn_0.4Zn_0.6Fe₂O₄ ferrite prepared by the co-precipitation method has been presented. We have shown by means of X-ray diffraction that the resulting ferrite is made up of nanoparticles, and that the average size of these nanoparticles calculated with the Scherrer formula depends upon the sintering temperature. When the sintering temperature is increased from 500 to 900 °C, the average nanoparticle diameter varies from 19.3 to 36.4 nm. The nanoparticle phase is further confirmed by scanning electron microscopy (SEM). Both results are found to be in good agreement. The magnetic properties are explained on the basis of the single-domain and multi-domain theory.     

Effect of rotating magnetic field on microstructure formation of directionally solidified Sn–1.6Cd peritectic alloy

In order to investigate the effect of rotating magnetic field on the microstructure formation of peritectic alloys, directional solidification experiments of Sn–1.6Cd peritectic alloy have been conducted under different rotating magnetic field conditions. The directional solidification microstructure of Sn–1.6Cd peritectic alloy changes from banded structure to axisymmetric isolated banded structure to axisymmetric oscillatory tree-like banded structure and to single primary phase structure when the magnetic Taylor number of forced-melt flow generated by a rotating magnetic field increases from 0 to 91 to 364 and to 1456. The second and third banded structures are observed in a peritectic alloy for the first time. The results indicate that it is possible to control solidification microstructure and prepare a single primary phase structure by using a rotating magnetic field during directional solidification of peritectic alloys. The experiments show that the effect of forced-melt flow on solute distribution transforms from solute buildup to homogenization with an increase in the magnetic Taylor number. The formation mechanisms of those structures are also discussed.     

Bulk and surface properties of liquid Sb–Sn alloys

The mixing behaviour of liquid Sb–Sn alloys has been described in terms of energetics and structure through the study of their thermodynamic, surface, transport and structural properties by using the Complex Formation Model (CFM) in the weak interaction approximation and by postulating SbSn chemical complexes as energetically favoured. The new Sb–Sn surface tension experimental data, obtained by the pinned drop method at temperatures ranging from 513 to 1023 K, have been analysed in the framework of the CFM and compared with the calculated values as well as with the corresponding literature data. The structural characteristics of Sb–Sn melts are described by the two microscopic functions, i.e. the concentration fluctuations in the long-wavelength limit and the Warren–Cowley short-range order parameter.     

On the control of microstructure in rapidly solidified Nd–Fe–B alloys through melt treatment

Rapidly solidified (RS) Nd₂Fe₁₄B alloys were prepared by melt-spinning under different melt treatment conditions i.e., the melt temperature was varied prior to ejection onto the quenching wheel. X-ray diffraction, transmission electron microscopy, thermal analysis and magnetic measurement were conducted on the as-quenched alloys to investigate their structural and magnetic characteristics. RS Nd₂Fe₁₄B alloys may display a variety of microstructures depending upon the thermal history of the melt before ejection: it was possible to synthesize an entirely amorphous structure, a partially amorphous structure containing nuclei and/or nanophases and a nanocrystalline structure. The relationship between the formation of crystalline nuclei or nanophases and the thermal history of the melt was studied. A lower melt ejection temperature produced a nanocrystalline microstructure, while higher melt ejection temperatures (T>1723 K) largely eliminated the presence of nuclei and associated nanophases and produced an amorphous product. The experimental results indicated that optimization of the melt treatment conditions will produce rapidly solidified Nd–Fe–B alloys with a more uniform microstructure.     

Influence of alloying elements on structure and some physical properties of quenched Sn–Sb alloy

We study the influence of ternary and quaternary alloying elements (Pb, Cd, Cu or Cu–Pb and Cu–Cd) on structural, electrical, hardness and other mechanical properties of Sn–Sb alloys (using an X-ray diffractometer and optical microscope, the double bridge method, Vickers hardness tester and the dynamic resonance method) to produce the best alloy for bearing applications. Adding Cu or Pb to Sn–Sb alloys improves their bearing properties, such as the mechanical properties (elastic modulus, internal friction, hardness and fracture strain) and thermal conductivity. Also, adding Cu, Pb or Cu–Pb to Sn–Sb alloys makes them excellent in their bearing applications and environmental hazards when compared with the Pb ₈₈Sn ₁₀Cu ₂ alloy for automotive applications (FIAT Normalizzazione) and the lead-based Babbitt bearing alloy.     

Cyclic deformation and fatigue cracking behaviour of polycrystalline Cu,Cu–10 wt% Zn and Cu–32 wt% Zn

The cyclic deformation behaviour of polycrystalline Cu, Cu–10 wt% Zn and Cu–32 wt% Zn was systematically investigated in the plastic strain amplitude range of 1 × 10^?4–4 × 10^?3. The differences in the cyclic stress–strain (CSS) responses and fatigue cracking behaviour between Cu, Cu–10 wt% Zn and Cu–32 wt% Zn were compared. It was found that the occurrence of a cyclic saturation for Cu–10 wt% Zn and Cu–32 wt% Zn strongly depends on the applied strain amplitude, whereas polycrystalline Cu always displays cyclic saturation. Surface deformation morphologies were analyzed by scanning electron microscopy (SEM). One of the major features observed is that the slip bands become increasingly homogenous with Zn addition. The fatigue cracks were found to frequently nucleate along the annealing twin boundaries (TBs) in Cu–10 wt% Zn and Cu–32 wt% Zn, but not in polycrystalline Cu. Based on these experimental results, the cyclic deformation response and fatigue cracking behaviour are discussed, and a developed TB cracking mechanism is proposed to explain the difference in fatigue cracking mechanisms in Cu, Cu–10 wt% Zn and Cu–32 wt% Zn.     

Effect of copper concentration on atomic site occupation by Fe ions and magnetic properties of (PrDy)–(FeCo)–B alloys

The effect of small copper additions (to ～6 at %) on the distribution of iron ions in six crystallographic sites of the unit cell of the main magnetic phase (PrDy)₂(FeCo)₁₄B has been detected. An increase in the copper concentration leads to a decrease in the 8j₁ site occupation by iron ions. Independently of the presence of copper, the temperature dependences of the saturation magnetization of all samples have a minimum which can correspond to the presence of a low-temperature phase or a compensation point in grain boundary regions of the (PrDy)₂(FeCo)₁₄B main magnetic phase. The alloys under study are not additive sets of all phases in their composition, but behave as new materials with the mutual influence of phases on each other.     

Effect of composition and light intensity on the electrical properties of Sn–Sb–Se glassy films

Electrical and photoelectrical measurements have been performed on Sn_xSb₂₀Se_70-x (8≤x≤16) glassy films. The dc activation energy, optical gap and photoconduction parameters show a typical variation near x=10 composition indicating the occurrence of a rigidity percolation threshold in the present system. The photosensitivity increases with the increase in Sn content up to x=14 and an abrupt decrease for x=16 composition. Negative photoconductivity region have been observed in the higher temperature side for samples with x=10 and 16. This system belongs to the type II category of photoconductors. The results are explained on the basis of a change in the density of localized states present in the mobility gap with the change in the composition. PACS 71.20.Nr; 72.20.-I; 78.66.Jg; 81.05.Gc; 73.50.Pz