Differences between grain boundary sliding with crystal slip and that without it are investigated by the use of orientation controlled cadmium bicrystals.
Without crystal slip, the rate of grain boundary sliding varied in proportion to applied stress and was controlled by grain boundary diffusion. With crystal slip, the rate of grain boundary sliding was found to vary in proportion to the square of applied stress and the activation energy for grain boundary sliding was almost equal to that of volume diffusion.
McLean’s model for grain boundary sliding with crystal slip is developed by assuming that the number of dislocations in the grain boundary is proportional to shear stress on the slip system. It is found that the model can explain the variation of grain boundary sliding rate with changes in shear stress on the slip systems.

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The fatigue and fracture characteristics of polycrystalline Cu-Al-Ni shape memory alloys have been investigated by examining the effect of quenching condition on intergranular cracking, by tensile and fatigue testing and by observing fracture surfaces. The tensile and fatigue tests have been carried out for three deformation modes; elastic deformation of the matrix crystal, pseudoelastic deformation due to a stress-induced martensitic transformation in the matrix state, and deformation in the martensitic state. As a result, pseudoelastic deformation due to stress-induced martensitic transformation was found to have the most deleterious effect on the intergranular cracking. Based on the experimental results, a model for the intergranular cracking was proposed in view of the transformation strain associated with a stress-induced martensite. This model can elucidate the degree of resistance to intergranular cracking in various shape memory alloys.

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Fe_1−xMn_x sputtered alloy films made under several Ar gas pressures, P_Ar’s, have been investigated by X-ray diffraction measurements. The single bcc phase region extends up to about x=0.2 independently of P_Ar. However, in the Fe_1−xMn_x sputtered alloy films made under low P_Ar the bcc phase shows a larger lattice constant than that in the Fe–Mn bulk alloys, while in the films made under high P_Ar the bcc phase shows almost the same lattice constant as that in the bulk alloys. After being annealed at 470 K for two hours, the metastable bcc phase is still preserved being accompanied with a structural relaxation. After being annealed at 670 K for two hours, on the other hand, a phase separation into the thermally equilibrium bcc and fcc phases takes place, probably because the atomic diffusion at low temperatures is enhanced by a large amount of lattice defects contained in the Fe_1−xMn_x sputtered alloy films.

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Distribution and density of dislocations in Cu and Cu–Al dilute alloy crystals grown with [321] orientation were studied by an etch pit technique. In Cu crystals, dislocations were always arranged into a network of subboundaries and distributed randomly within subgrains with a total density of dislocations 1.6×10⁹–7.0×10⁹ m⁻². On the other hand, in Cu–Al dilute alloy crystals, the lower dislocation density crystals free from subboundaries were grown with a somewhat high degree of reproducibility, though different kinds of subboundaries and dislocation clusters were produced in some cases. XMA analysis of the cluster center revealed the presence of an aluminium oxide particle at the core from which a succession of prismatic dislocation loops was punched out forming a rosette-like pattern. The lowest dislocation density of 3.0×10⁸ m⁻² was obtained for a subboundary-free crystal containing 1.0 at%Al. These effects of Al were discussed on the basis of some concepts of dislocation nucleation due to solute atoms in melt-grown crystals.

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The local frequency spectra of hcp metals (Mg, Zn, Cd) were calculated by the recursion method along two directions, one parallel to the hexagonal c-axis and the other perpendicular to the c-axis. The force constant matrix was computed by the interatomic potentials (Lennard-Jones potential) or taken from the experimental values if they were available. The mean-square atomic displacements were also computed and compared with the experimentally observed ones. Discussions were given on the usefulness of the Lennard-Jones potentials for hcp metals.

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The extraction of some metal ions with the sodium salt of di-2-ethylhexylphosphoric acid (D2EHPA) is investigated in order to clarify the extraction characteristics and mechanism. The sodium salt of D2EHPA extracts metal ions primarily by the exchange reaction of sodium ion to the metal ion and the extractability depends on the initial concentration of the extractant and metal ions or these factors and the initial pH . The conversion of D2EHPA into the salt form enables one to obtain the high and constant extractability from an acidic solution regardless of the initial pH over a wide pH range.

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Experiments were carried out to clarify the role of zirconium to improve strength and stress-corrosion resistance of Al–6%Zn–1.8%Mg and Al–6%Zn–1.8%Mg–1.5%Cu alloys. Addition of approximately 0.2% zirconium followed by ingot homogenizing at 723 K for 28.8–57.6 ks improves remarkably strength and stress-corrosion resistance of those alloys. The reason why these properties are improved is due to formation of subgrains caused by zirconium-bearing particles. That is to say, these particles pin up subgrain boundaries and retard recrystallization when they grow up to be 10–50 nm and are distributed at intervals of 0.1–0.5 μm by ingot homogenizing in the above condition.
On the other hand, quench sensitivity of zirconium-bearing alloys increases in the above condition, since an equilibrium phase (MgZn₂ etc.) precipitates at the misfit surface around zirconium-bearing particles during slow quenching. However quench sensitivity of zirconium-bearing alloys does not so much increase as that of chromium-bearing ones, because it is considered that the area of misfit surface of the former alloys is smaller than that of the latter ones.

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