Fiber textures in copper and iron filaments produced by the glass coated melt spinning under various conditions are investigated by the X-ray diffraction method. A single [100] fiber texture is observed for copper filaments and a single [111] texture for iron.
The distribution of crystallite orientation is evaluated by the orientation function f=1⁄2(3⟨cos²\varphi_j⟩−1), where \varphi_j denotes the angles between the fiber axis and crystallographic principal axes, and ⟨cos²\varphi_j⟩ represents the mean square of directional cosines \varphi_j. The orientation functions of copper and iron filaments are evaluated from the diffraction intensity distribution along the Debye rings for {200} and {110} planes. It is found that the degree of sharpness in fiber texture increases with winding speed in the spinning process.

View full abstract

The mechanical properties of silver filaments produced by the method of glass coated melt spinning are studied.
In spite of a large scatter in the data obtained, it is apparent that there is a size effect on the strength of silver filaments except for the filaments spun at a winding speed of 238 m/min (sample 3). The silver filament of 4.7 μm in diameter has a tensile strength of 37 kg/mm² and an elongation of 1.5%. A large scatter in the elongation is observed for sample 3. The slip lines are observed on the fracture surface of the deformed filaments except for sample 3.
These behaviors are related to the fiber texture. The double ⟨100⟩+⟨221⟩ fiber textures are observed in sample 3, and a single ⟨100⟩ fiber texture, in the other filaments. The maximum degree of orientation is observed at a winding speed of 200 m/min.
These results are explained from the point that the twin deformation occurs on the processing of melt spinning at a winding speed of 238 m/min.

View full abstract

The oxidation behavior of the heat-resistant Fe-base alloy Incoloy 800 has been investigated in the vicinity of 1000°C under oxygen pressures ranging from 1×10⁻⁴ to 2×10⁻¹ atm. The rate of oxidation has been determined by the weight gain using a Cahn RG Electrobalance. Metallographic, electron microprobe and X-ray diffraction studies of the oxidized specimens have been carried out. The rate of oxidation is parabolic but tends to slightly decrease with the progress of oxidation. Cold rolling of the specimen accelerates the rate of oxidation. The dependence of the oxidation rate upon oxygen pressure is slightly smaller than that theoretically expected for the scale of pure Cr₂O₃. The oxidized specimen has a layer structure of the outer porous scale, the inner dense scale, the complicated scale-substrate interface region and the internally-oxidized substrate in sequence from the outer side. The outer scale is principally composed of oxides of Cr and Mn, but it also contains smaller quantities of oxides of Ti, Fe, Ni etc. Oxygen partial pressure of the reaction affects the composition of the outer scale. The inner scale is principally composed of Cr₂O₃. Most of the oxides of Al and Si are present in the scale-substrate interface region and the internally-oxidized substrate region. The existence ratio of the spine1 phase against the rhombohedral phase in the outer part of scale considerably increases with the progress of oxidation.

View full abstract

An attempt was made to apply the TIE method at room temperature to measurement of the activities in liquid In–Hg alloys.
The accuracy in the present study cannot be assumed better than the studies at the elevated temperatures contrary to our expectation, but the measured activities of both components seem to be reasonable compared with the literature values.
It is to be noted that there appeared constant activities in the concentration range of N_In=0.3 to 0.4.

View full abstract

The measurements of internal friction Q⁻¹ under tensile loading and of mechanical properties have been carried out for open-melted Fe–Mo alloys containing 0∼16% Mo. The Q⁻¹ values at a frequency of 0.3∼1.1 Hz linearly increase with the maximum shear strain amplitude ε_m and decrease after reaching a peak at ε_m=about 1.2×10⁻⁴. The peak height gradually diminishes with increasing tensile load. The Q⁻¹ values are as small as 0.5×10⁻³ in the cold-worked state, whereas they are considerably large in the annealed state and increase with annealing temperature. The highest Q⁻¹ value of 58×10⁻³ is obtained with an Fe-6% Mo alloy annealed at 1200°C for 1 h.
The results obtained indicate that Q⁻¹ increases with temperature in the range of 20∼600°C and decreases rapidly with the increase in external magnetic field. The fairly large value of Q⁻¹ in these alloys are mainly due to the effect of magnetomechanical hysteresis. The mechanical strength of Fe–Mo alloys increases with Mo content; for example, an Fe-6% Mo alloy shows a tensile strength of 390 MPa and a yield strength of 200 MPa, an elongation of 29% and Vickers hardness 135, when subjected to annealing at 1000°C for 1 h.

View full abstract

In order to determine the stability of magnetic properties, the remanence B_r at high temperatures has been mainly investigated for Co-36% W and Co-26% Mo alloys subjected to heat treatment at various temperatures. A very small fluctuation of 0.3% in B_r has been observed for 530 h at 720°C in the former alloy and 2000 h at 660°C in the latter. This result shows that these alloys have better stability in B_r at higher temperatures than an Alnico-type alloy obtained by McCaig.

View full abstract

Magnetically soft single crystals of weak ferromagnetic semiconductor NiS₂ were grown using highly pure sulfur (99.9999%) and nickel (99.99%) powders. Measurements of the Hall effect, electrical conductivity, magnetization, magnetic hysteresis loop and magnetic susceptibility were made on these crystals.
The Hall coefficient R_H was positive over the temperature region of 4.2∼140 K and R_H at 77 K was about 1.5 cm³/C. The Hall voltage at 4.2 K (below T_c) showed a complicated field dependence which differed from the behaviour of the magnetic hysteresis loop. The electrical conductivity was measured from 4.2 to 300 K. Measurements of magnetization M and magnetic susceptibility χ were made from 4.2 to 140 K. M at 4.2 K was 1.1 e.m.u./g (H=16.8 kOe) and χ had a broad maximum at about 50 K. The hysteresis loop measurement was made with a torquemeter at 4.2 K in magnetic fields of −21∼+21 kOe.

View full abstract

The transformation twins in a number of partially twinned ferrous martensites are typically featured as planar parallelogram shapes when viewed in the transmission electron microscope. The crystallography of such twin segments has been the source of a number of investigations, and it has been pointed out that difficulties in interpretation may be ascribed to specimen buckling. Contrary to previous considerations, Oshima and Wayman proposed the alternative view that the short edges of the twin segments (previously called the twinning direction) rather than the long traces may correspond to the intersection of the twins with the specimen surface (surface trace). This suggestion came from the study of thin foil {225} martensites where the substructure is somewhat variable and not well-defined. The present work was undertaken to examine this different hypothesis by using an Fe-33% Ni martensite, for which the habit plane is {3 10 15} and the substructure is rather well characterized after transformation in bulk specimens.
In the present work, judging from morphological observations of the twin images, the twin plane was concluded to correspond to the long trace, and this conclusion was strengthened by coupling trace analysis with the predictions of the phenomenological crystallographic theory. The conclusions from the study of {225} martensites were derived principally from studies of a specimen with [011] orientation, and in the present case a number of difficulties were experienced when [011] foils were analyzed. In such cases, the trace analysis indicated that the short twin segments correspond to the twin trace, but morphological observations indicated the opposite, i.e., the long trace corresponds to the twin trace. It was thus found that trace analysis solutions for the [011] beam orientation are not necessarily unique. Some other difficulties associated with trace analysis are discussed as well as apparent rotations of the twin plane from buckling or tilting.

View full abstract