Elastic neutron scattering technique has been employed to study the short-range-ordering of deuterium atoms in α-TaD_0.55 in the temperature range 65–80°C. The intensity distribution of 1/2 1/2 0 type diffuse pseudo-Bragg reflections is observed. Intensities of the 1/2 1/2 0 type diffuse reflection are not much temperature dependent as in the case of those observed in α-VD_0.5 and α-NbH_x=0.05−0.6. Warren-Cowley’s short range order parameter and the short range displacement are calculated.
The existence of almost spherical microdomains having a β₂-TaD_0.5-type structure with a diameter of about 1.2 nm is concluded from the present neutron diffraction work.

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Two prediction methods for the site occupation of the third elements in L1₀-type TiAl alloys have been proposed. One was derived from the empirical rule where the change of lattice parameters, a and c, of the TiAl phase with the addition of third elements is taken account of. Here, the parameters a and c satisfied the following two conditions. (1) The axial ratio, c⁄a, decreases with increasing the atom diameter ratio, D_α⁄D_β. Here, D_α or D_β is the average diameter of atom which occupies the α- or β-sublattice in the L1₀-type crystal lattice. (2) The ratio of D_α⁄D_β and the value of (D_α−(a⁄\sqrt2))⁄D_β converge into a narrow range. The other was obtained from the interaction parameters of the constituent atoms in the TiAl phase. In addition, the amount of site occupation of the third elements, Ag, Fe, Ga, Ni and Pt, and that of host elements in the TiAl phase were determined by an X-ray analysis. The occupation amounts of the additives predicted by the former method agreed well with those determined by X-ray analysis.

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The atom location of the third element X (Cr, Mn, Fe, Co or Cu) in Ti_48.5Ni_48.5X₃ alloys has been examined by electron channelling enhanced microanalysis (ALCHEMI). As a result, Fe and Co atoms were located at the Ni atom site preferentially, while Cr, Mn and Cu atoms were at both the Ni and Ti atom sites with nearly the same ratio. In order to understand these results from the viewpoint of thermodynamics, free energy of the system was calculated on the basis of Bragg-Williams approximation, taking account of the configurational entropy. The atom configuration for which the free energy was minlmized was in good agreement with the experimental results.

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A high energy type ball-milling machine for mechanical grinding (MG) was used to examine its effectiveness of redistributing solute in water atomized Cu–Pb alloy powders and the process of the structure deformation of the Cu–Pb powders was discussed. The Cu–Pb powders were deformed and pulverized sequentially from their surfaces to the inner parts and pulverizing of the powders were completed after MG periods of 10 h. The structures of the sufficiently pulverized powders were composed substantially from the crystallites the diameter of which was a minimum of 50 nm and also in some parts from an amorphous-like phase. It was suggested that the crystallites are produced from an amorphous-like phase while it is unstable at ambient temperatures of the ball-milling machine. The results of DSC measurements carried out on these MG powders showed the stored energy in the MG powders was about one order of magnitude lower than the mixing free energy of the supercooled liquid Cu–Pb alloy and not enough to amorphize completely this alloy.

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It has been found that amorphous La₅₅Al₂₅Ni₂₀ and La₅₅Al₂₅Cu₂₀ alloys exhibit a distinct glass transition and the temperature span between T_g and T_x, ΔT_x(=T_x−T_g) exceeds 50 K. This is the first evidence for the formation of an amorphous phase with ΔT_x above 50 K in a metal-metal type system. With the aim of clarifying the glass transition behavior and the properties of supercooled liquid in the metal-metal type amorphous alloys, the changes in fundamental properties of specific heat (C_p), viscosity (η), tensile yield strength (σ_y), tensile elongation including elastic elongation (ε_f) and viscoelasticity in the glass transition region were examined for both amorphous alloys. The transition brought about significant changes in the above-described properties, i.e., for the La₅₅Al₂₅Ni₂₀ alloy, an increase of C_p by 12 J/mol·K and ε_f from 2.43 to 188% and a dramatic decrease of η to below 10¹² Pa·s and σ_y from 710 to 3.47 MPa. In addition, the complex modulus decreased from 33.5 to 1.79 GPa and the loss tangent increased rapidly from 9×10⁻³ to 3.32. Similar significant changes in the fundamental properties were also observed for another La₅₅Al₂₅Cu₂₀ amorphous alloy and hence these amorphous alloys were concluded to be typical glassy materials.

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Amorphous Al₈₈Y₂Ni_10−xM_x (M=Mn, Fe or Co) alloys containing nanoscale fcc-Al particles form in the composition ranges 0 to 2 at% Mn and 0 to 5%Fe or Co and exhibit tensile fracture strength (σ_f) and hardness (H_v) higher than those of amorphous single phase alloys with the same compositions, without detriment to good bending ductility. The particle size of the fcc-Al phase increases in the range of 2 to 30 nm with a decrease of cooling rate and decreases with an increase of M content. The H_v and Young’s modulus (E) for the mixed Al₈₈Y₂Ni_10−xFe_x alloys increase monotonically with increasing volume fraction of the fcc phase (V_f), while the σ_f shows a maximum value in the V_f range of 5 to 25%. The increase of σ_f in the V_f range below about 25% is presumably due to an enhancement of the resistance to shear deformation caused by the nanoscale fcc particles which have higher mechanical strengths as compared with the amorphous phase with the same compositions. On the other hand, the decrease of σ_f with further increasing V_f is due to an increase in embrittlement tendency. The maximum σ_f increases with increasing M content and the degree of the increase is greater in the order of Mn>Fe>Co. This order is presumed to result from the magnitude of attractive bonding force between M and the other constituent atoms.

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A low pressure casting of Mg–Cu–Y melts into copper molds was found to cause amorphous bulks in a cylindrical form. The maximum diameter of the amorphous cylinder (D_c) shows a significant compositional dependence and reaches a maximum value of 4.0 mm for Mg₆₅Cu₂₅Y₁₀. The compositional dependence of the D_c is similar to that for the temperature span of the supercooled liquid region, ΔT_x(=T_x−T_g). The similarity is presumably because the alloy with large ΔT_x has a high resistance against the nucleation and growth of a crystalline phase resulting from the formation of a disordered structure with a more dense random packing and an optimum bonding states. The compressive proof stress at an elongation of 0.2% (σ_p) for the Mg₈₀Cu₁₀Y₁₀ cylinder was 822 MPa at room temperature and the fracture occurred along the shear plane. The σ_p remains unchanged up to 350 K and then decreases significantly with increasing temperature, accompanied by the change in the deformation mode from inhomogeneous to homogeneous type. There is no appreciable difference in the features of mechanical strengths and deformation behavior between the bulk and ribbon samples, indicating the similarity of the disordered structure.

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Effect of slag basicity on selenium distribution between slag and metal phase was studied at 1473 K under reducing conditions by equilibrating sodium-borate slags of different Na₂O/B₂O₃ ratios (0.527 to 0.864) with Cu–Se alloys containing different initial selenium amounts. Results show that there is an improvement in Se transfer from metal phase to slag with the increase in slag basicity. The Se distribution pattern at equilibrium between slag and metal follows a quantitative relationship ln (%Se)/[%Se]=4b−2.76 where b is the slag basicity.

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In recent times there is considerable spurt in R & D activities relating to Zinc-Aluminium foundry alloys for applications in bearings. In spite of the fact that zinc alloys have excellent properties like fluidity, lower melting points and excellent alloying behaviour, the zinc foundry alloy have not been finding the expected potential of application. This is due to the fact that trace amounts of impurities like lead, cadmium and tin aggravate the chances of intergranular corrosion and premature failure.
In the present work various fluxes have been tried with a view to improving the microstructural features in Zn-8Al, Zn-12Al alloys. The results indicate that the use of a special flux improves the wear and corrosion resistance. Detailed metallographic investigations were carried out and are discussed in the paper. In the preparation of the alloys only the indigenously produced electrolytic grade zinc has been used which contains some amount of lead.
The investigation showed that this flux treatment produces Zinc-Aluminium alloys having properties comparable with those produced using special high grade zinc.

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