The ordering process from short range order to long range order in a Cu-25.7 at%Pt alloy was studied by electron diffraction and dark field microscopy. The alloy as quenched from 923 K was found to give typical diffuse scatterings in the diffraction pattern, indicating that the alloy is short range ordered. When the as-quenched alloy is annealed at 693 K, 793 K or 823 K, the short range order develops at the early stage to a microdomain structure where numerous ordered particles about a few nanometers in diameter are embedded in a disordered matrix. The ordered particles have a long range correlation of antiphase with one another. By further annealing at 693 K or 793 K, the particles grow up to large domains of L1₂ or L1_2−s, respectively, while at 823 K the alloy has an equilibrium state of a mixture of (Al+L1_2−s). The ordering processes observed can be described in general in terms of “evolution of ordering wave”. When the ordering wave increases both of its amplitude and wavelength with annealing, L1₂ develops. If the wave increases its amplitude, but maintains its wavelength, L1_2−s is formed.

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Precipitation in nickel-rich Ni–Al–Mo ternary alloys in the temperature range from 873 to 1373 K has been investigated by transmission electron microscopy, selected area electron diffraction and hardness measurements. Various stable and metastable phases, γ′, NiMo(δ), Ni₂Mo, D0₂₂–Ni₃Mo and Ni₄Mo, and short range order (SRO) are formed during ageing depending on the alloy composition and ageing temperature. Constitutional diagrams showing the fileds in which each precipitate forms are presented. The γ+γ′ two phase region extends to the lower Al region at low temperatures. Ni₂Mo, D0₂₂–Ni₃Mo and SRO form in the alloys of a wide compositional range. Ellipsoidal or polyhedral Ni₂Mo, plate-like Mo and cuboidal γ′ are considered to be important in strengthening the Ni–Al–Mo ternary alloys. Precipitation of globular δ phase occurs at high temperatures only in the alloys with high Mo content.

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(Ti_0.74Mo_0.26)C_0.96 (δ phase) and Mo–1.5Ti–1.2C (β phase) solid solutions, and hypo Mo–10TiC and hyper Mo–40TiC eutectic composites were prepared and deformed by compression in a temperature range from 285 to 2270 K and in a strain-rate range from 5×10⁻⁵ to 7×10⁻³ s⁻¹. The strength of Mo–23.5TiC lamellar eutectic composite reported earlier and those of the hypo- and hyper-eutectic composites were analysed from the strengths of component δ and β phases.
It is found that the extremely high strength of the lamellar eutectic composite is due primarily to solution hardening of TiC by Mo, and that the δ phase undergoes an appreciable plastic deformation at and above 1470 K even at 0.2% plastic strain of the composite. The yield strength of the three kinds of composites up to 1470 K is quantitatively explained by the ‘rule of mixtures’, where internal stresses introduced by plastic deformation are taken into account. The magnitude of internal stresses in the component phases is evaluated on the assumption that both the components are equally strained. Above 1470 K, however, the evaluated yield strength is considerably larger than the measured strength, indicating that the effects of recovery of the internal stress and phase-boundary sliding become significant at such high temperatures.

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In order to clarify the mechanism of the so-called intermediate temperature embrittlement, Cu–GeO₂ dispersion-hardened alloys were tensile tested at various temperatures between room temperature and 900 K with the strain rate of 10⁻³ s⁻¹ or 10⁻⁴ s⁻¹. In the case of single crystals, elongation to fracture increased monotonically with increase in temperature. On the other hand, the ductility of polycrystals first decreased and then increased again, showing the ductility minimum associated with intergranular fracture at an intermediate temperature range around 600 K. The degree of such intermediate temperature embrittlement was sensitive to both the strain rate and the size of GeO₂ particles at grain boundaries. Microscopic observation of deformation and fracture characteristics of polycrystalline samples indicated that the initial decrease of ductility occurred concurrently with the occurrence of grain-boundary sliding and that the recovery of ductility at higher temperatures was due to the initiation of extensive recrystallization. It is concluded that in the intermediate temperature range local stress which concentrates near the GeO₂ particles on the sliding grain-boundary induces the formation of voids which eventually grow and coalesce to cause intergranular fracture. At higher temperatures, the stress concentration is relaxed by the recrystallization, resulting in the recovery of ductility. The effects of strain rate and particle size on the intermediate temperature embrittlement are also discussed in association with the occurrence and disappearance of the stress concentration.

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The emf of the following galvanic cells using zirconia solid electrolytes has been measured in order to obtain the standard free energy of formation of ZnO(s) in the temperature range from 818 to 986 K and the thermodynamic data of the liquid Au–Zn and Ag–Zn systems, for N_Zn=0.25–0.80 and N_Zn=0.27–0.85 in the temperature ranges from 918 to 1123 K and from 865 to 1152 K, respectively.
Pt/Ni,NiO/ZrO₂(+CaO)/Au–Zn,ZnO/Re–Pt
Pt/Ni,NiO/ZrO₂(+CaO)/Ag–Zn,ZnO/stainless steel.
The error arising from vaporization of zinc was carefully avoided in this study. The standard free energy of formation of ZnO(s) was determined:
ΔG_(ZnO)°⁄J·mol⁻¹=−698272+209.07T between 818 and 986 K.
Activity curves obtained show considerably negative deviations from Raoult’s law, especially in the Au–Zn system, suggesting a large affinity of zinc for gold and silver.
The thermodynamic properties of liquid alloys composed of IB metals (Cu, Ag and Au) and zinc have been discussed in terms of the alloy solution theory of Engel. Namely, the activities and the heats of mixing for liquid alloys seem to be consistently explained on the assumption that the filling of d shell is incomplete for the IB metals as well as the transition metals, whereas it is complete for zinc.
The activities and the heats of mixing of liquid Cu–Zn and Ag–Zn alloys are quite different from those of the liquid Au–Zn system, in which the activities show considerably negative deviations and the heats of mixing are exothermic, in the whole concentration range, owing to larger differences of electronegativity factor in the gold alloys.

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On low carbon steel specimens vacuum carburized at temperatures in the range from 1193 to 1313 K in a methane atmosphere at pressures ranging from 13 to 80 kPa, carbon content profiles within the specimens were determined from a succession of grindings and carbon analyses with a vaccum type emission spectrometer. The total amount of carbon which entered each specimen through the surface during a carburizing period was graphically calculated from the profile, and the rate of carburizing was evaluated from the amount of carbon. It was found that the rate of vacuum carburizing with methane had the temperature dependence several times as strong as that of gas carburizing. A mathematical model for calculation of such carbon content profiles is presented. The model in which the variation of carbon diffusion coefficient in steel with carbon content was taken into consideration predicted accurately the surface carbon content and case depth of vacuum carburized steel.

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An experimental study for continuous production of amorphous powders by flame-spray quenching has been carried out on Fe–Ni–P–B, Ni–Si–B and Co–Fe–B alloys. The spray-quenching equipment consisted of a thermal spray gun of the oxyacetylene type, a rotating copper substrate wheel and a powder collecting system. The substrate wheel was rotated at circumferential velocities below 2.2 m/s. The progress of vitrification of the sprayed powders increased with increasing circumferential velocity of the wheel. By regulating the circumferential velocity of the wheel at approximately 2 m/s so as to suppress the lowering of the cooling rate of liquid metal impinging onto the substrate and partial crystallization of sprayed amorphous phase, once formed on the substrate, due to the flame and liquid metal stream itself from the gun, amorphous alloy powders have continuously been produced for the Fe-, Ni-, and Co-based alloys. The amorphous alloy powders produced at a circumferential velocity of 2.2 m/s were composed mostly of circular or elliptic flakes with irregular periphery. The thickness of the flaky powders was in the range from 5 to 30 μm and the particle size decreased with increasing circumferential velocity in the range below about 350 μm.

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Uniaxial tensile tests and hydraulic bulge tests were carried out for two differently textured sheets of pure titanium. The sheets were previously examined for the orientation distribution of grains, containing the orientation relation between neighboring grains. The deformation behavior of the titanium sheets was examined in connection with the effect of the orientation difference between neighboring grains on the deformation mechanism of grains.
In the case of the uniaxial tensile test, the correlation in the 0.2% proof stress among differently textured sheets and different test directions can be explained by the preferred orientation of the sheets. However, the plastic flow curves are influenced by the orientation difference between neighboring grains. In the sheets rolled unidirectionally at 1173 K, the orientation difference of the c-axis between neighboring grains is distributed broadly in the whole range from 0 to π/2. The anisotropy of the flow stress is smaller than that of the 0.2% proof stress, and the slope of the stress to the strain is larger than that of the sheets cross rolled at 873 K.
Stress-strain curves and effective stress-effective strain curves of two differently textured titanium sheets, which were estimated from the hydraulic bulge test using the Hill’s theory for the anisotropy, were examined. Since the preferred orientation in the sheets cross-rolled at 873 K is (0001)[10\bar10] and the orientation difference of the c-axis between neighboring grains is small, the deformation mechanism of grains under the biaxial tension is extremely different from that under the uniaxial tension. Therefore, as pointed out previously, the overestimation of the anisotropy by the r value takes place. Though the r values of the sheets rolled unidirectionally at 1173 K are relatively high (from 2 to 5), the difference in the deformation mechanism of grains between different loading conditions is small because of the plastic constraint among neighboring grains. As a result, the estimation of the anisotropy by the r value is not so irrelevant.

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In connection with hot shortness of tin bronzes, the ductility of a Cu-8 mass%Sn binary alloy and of the alloys singly containing B, Mg or P of about 0.1 mol% was investigated in detail at elevated temperatures up to 1073 K. All the alloys showed markedly poor ductility at temperatures from 673 to 873 K accompanied by intergranular fracture on account of so-called intermediate temperature embrittlement. The ductility was improved to a greater extent at higher temperatures in B-bearing and Mg-bearing alloys, but to a lesser extent, in the binary and P-bearing alloys. The marked improvement in ductility which was accompanied by transgranular fracture was commonly observed regardless of strain rate and grain size in the B-bearing alloy. This alloy showed excellent ductility together with fine recrystallized structures which was caused by dynamic recrystallization at higher temperatures. Recrystallization temperatures, however, were substantially the same in four sorts of alloys. In the binary and P-bearing alloys, intergranular fracture at higher temperatures was shown to start from the specimen surface. This fact suggested that the strength of the grain boundary of these alloys was reduced especially near the surface. Based on the result of oxidation experiment, the decrease in the grain boundary strength was surmised to be inhibited in B- and Mg-bearing alloys by the suppression of oxygen penetration through the grain boundary.

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