The oxygen pressure dependence of electrical conductivity for solid solution (UyTh1−y)O2+x was measured in the oxygen pressure range 1 to 10−25 atm at 699° and 882°C. Between the oxygen pressure dependence of conductivity and the mean valence of U ion in the solid solution, there exists a correlation which is independent of the value of y. In the range of about 4.02 to 4.3 in the mean valence of U ion, the conductivity is considered to be due to a polaron hopping mechanism similar to that of UO2+x proposed by Aronson et al.
The thermodynamic activities of iron in iron-nickel alloys have been determined by e.m.f. measurements on solid-electrolyte oxygen concentration cells over the temperature range 750°∼1150°C. The activity of iron in the alloy system exhibits slightly positive departures from ideal solution behavior in iron-rich alloys and negative departures in nickel-rich alloys. The activities of nickel, deduced from the Gibbs-Duhem equation, indicate negative departures from ideality in all compositions. The relative integral molar excess entropies are positive for all the composition studied. However, consideration of magnetic factors suggests that the configurational excess entropies are negative and that the solid solutions are non-random. The heats of mixing vary from endothermic values to exothermic values with increasing nickel content; inferring that the non-random behavior suggested by the presumed configurational excess entropies is clustering at iron-rich compositions and short-range ordering at nickel-rich compositions.
As 18-8 stainless steel has excellent mechanical properties at cryogenic temperatures, it is preferably used as structural material for cryogenic appliances. Therefore, it is very important to know the details of its mechanical properties at these temperatures. But comparatively few works have been done on mechanical properties of 18-8 stainless steel at temperatures below liquid nitrogen temperature. Then, the authors conducted tensile tests of 18-8 stainless steel at temperatures between room temperature and −271°C using an apparatus designed for testing materials at cryogenic temperatures, and discussed the details of plastic deformation and the effect of martensitic transformation on it. A brief summary of the results is as follows. (1) Serrations are observed in the plastic deformation region of load-extension curves at temperatures below −221°C, and become remarkable with decrease in temperature. Load drops in the yielding region is a little more remarkable than those in the uniform elongation region at −269° and −271°C. (2) The rate of strain hardening increases in general with decrease in temperature, and has a tendency to decrease at the end of deformation at temperatures between room temperature and −245°C. But the rate of strain hardening does not decrease even at the end of deformation at −269° and −271°C. (3) 18-8 stainless steel yields 3∼4% of plastic deformation before the yield point at temperatures below −100°C. This phenomenon is thought to have a close relationship with the formation of martensite at the beginning of deformation. (4) The uniform elongation region at −269° and −271°C consists of two stages that show a different tendency in the change of strain hardening rate, and it does not contain the region of parabolic strain hardening just before the narrowing. The uniform elongation region in which the formation of α′ martensite is predominant directly leads to the narrowing at −269° and −271°C.
The facing tests with the ranges of cutting speeds 10∼1450 m/min have been conducted on disc type silumin, which is an eutectic aluminium alloy containing 13% silicon and is not easy to obtain a good cutting surface in the aluminium alloy, in order to investigate the influence of cutting conditions on surface roughness. In addition, the obtained results are comfirmed by orthogonal cutting tests for the purpose of clarifying the machining mechanism of the alloy system. In this experiment, when the cutting speed is over 600 m/min, the cut surface is good and shows nearly the theoretical roughness calculated by the feed, the tool nose figure and the others. When the cutting speed is less than 200 m/min, especially 90 m/min, the cut surface is very poor because of the vigorous growth of built-up edge. In an intermediate cutting speed range, 300∼600 m/min, a good cut surface is obtained in the orthogonal cutting test, but no satisfactory result is obtained in the facing test owing to influence by side flowing and burnishing and in the latter case, the growth of built-up edge is not distinct by orthogonal cutting or facing.
As a severe tool wear in machining hypersilumin has given rise a controversy in practice, the cutting tests for turing and facing of Al-17%Si alloy and Al-23%Si alloy are experimented with a view to studying, mainly, a tool wear of sintered alloy tool and the flank deposit accompanying it. As a result, a built-up edge ceased to exist with a raise of cutting speed and at the same time a progression of tool wear became conspicuous, and a fan-shaped deposit began to adhere on the tool flank. With further raising cutting speed, a long ribbon-shaped deposit adhered on the flank. If a ribbon-shaped deposit adhered on the flank, the cutting resistance increased and the cut surface became deteriorated. The tool shape with a larger clearance angle was effective, whereas as the tool material, a less TiC-containing sintered tool was effective to tool wear. And a less flank deposit showed a longer tool life. In some cases grooving wear appeared in a softer material of Al-17%Si alloy. Furthermore, a tool wear formula which was applicable in facing with a wide cutting speed range was proposed. This formula agreed well with an experimental value.
A peculiar type of discontinuous yielding was found in β-brass which was deformed at elevated temperatures. The process is characterized as follows: (1) It is observed only in the specimen annealed at temperatures higher than the order-disorder transformation point (Tc) before the tensile test. (2) It is observed in a limited range of temperatures below Tc and is strongly affected by deformation temperature and strain rate. (3) It is not an abrupt change, and also does not accompany a Lüders band propagation. (4) It is not reproduciable even if the specimen is reloaded after interrupting deformation and annealing at testing temperature. Those experimental results are discussed from the point of view of the behaviour of superdislocation in β-brass. From the relation between a slip plane and a minimum energy plane of A.P.B. in β-brass, it is concluded that the yielding process is controlled by viscous climb of superdislocation which drags A.P.B. and hereby the increase of density of mobile dislocation, as proposed originally by Johnston, results in a pronounced process of the discontinuous yielding of β-brass.
The yield strength of Fe-7%Cr alloy and Fe-3, -7%V alloys was measured in the temperature range from 400° to 77°K. These alloys showed no appreciable alloy-softening, but stronger temperature dependence of yield strength than that of pure iron at temperatures lower than 150°K. In addition, alloying of chromium or vanadium lowered the critical temperatures and also the activation area for deformation. These behaviours are in contrast with those generally found in the alloys which show alloy-softening. The strong temperature dependence of yield strength in these alloys seems to be associated with the strong interaction between the alloying elements and interstitial impurity atoms.
The copper single crystals with the (513)[\bar121] orientation which is an ideal orientation of the pure metal type rolling texture of fcc metals were rolled under various conditions. The strain rate dependence of the stability of this orientation during rolling was studied by means of the reflective electron-diffraction analysis of lattice rotation and the slip line observation using replica techniques. The single crystals were rolled such that the rolling direction was (1) normal to the transverse direction (TD) and (2) parallel to the longitudinal direction (LD), referred to undeformed crystals. In the case of the rolling referred to TD, the lattice rotation from (513)[\bar121] to (211)[\bar111] via \simeq(513)[\bar455] was observed independent of the strain rates of 10−1/sec and 102/sec. This orientation changes may be connected with the shape change of the crystal resulting from the deformation. These would seem to indicate that the orientation of (513)[\bar121] is not stable for a single crystal during rolling deformation. In the case referred to LD, on the other hand, the stability of the (513)[\bar121] orientation depended on the strain rates. At the low strain rate rolling (10−1/sec), the initial orientation was retained up to high reductions, while at the high strain rate rolling (102/sec), the lattice rotation toward (101)[\bar121] occured gradually. It was found from the slip line observation that there are no changes in active slip systems and no marked differences in slip band configurations except for the degree of the fragmentation of slip bands, in both strain rates. These results were discussed from the view-point of dislobation structures comparing with the reported models for the formation of the (513)[\bar121] ideal orientation.
The strength of martensites of plain carbon steel (S35C) and two kinds of 13-Cr stainless steels (SUS 37 and SUS 53), which were dynamically marformed by impact loading was investigated by means of hardness measurement and compression test, and was discussed on the precipitation of carbide. The data was also compared with those of the same steels marformed statically. The results obtained are summarized as follows: (1) Effect of the deformation speed on the amount of work hardening is found for S35C martensite, whereas not almost for the other metals. A yield drop phenomenon, which may be caused by auto-tempering resulting from the rise of temperature during the deformation occured for dynamically marformed S35C during the compression test. (2) After tempering at low temperature, the strength of dynamically deformed martensites becomes 20 to 30 kg/mm2 higher than that of statically one, regardless of the amount of deformation. A yield drop phenomenon is also observed for all martensites deformed and tempered at low temperature. (3) By use of the extruction repliqca technique, it is confirmed that the precipitation of carbide during the tempering is suppressed and the particle size of the precipitates is small in dynamic deformation as compared with that in static one. High strength of martensites, which dynamically deformed and then tempered at low temperature is therefore believed to be provided by dispersion hardening resulting from fine precipitates of carbide. It is concluded from the results that for strengthening of martensite dynamic deformation is more favourable than the static one.
The arc on breaking contact has been observed by means of an oscilloscope in the range of applied voltage from 20 to 110 volts and of circuit current from 0.3 to 50 amperes at both d.c. and a.c. circuits for silver, tungsten, carbon and silver-cadmium oxide contacts. From the observations, it is found that length L, voltage e and current i of the arc are given by the following equations, (This article is not displayable. Please see full text pdf.) where E is applied voltage, I is short circuit current, Em is minimum arc voltage, Im is the minimum arc current, v is opening speed, ω is angular velocity, φ is phase angle, T is arc duration, t is time and K is constant. These equations hold for the materials of both thermionic emission and field emission (T−F mechanism).
The surface films on copper alloys has been studied by the immersion test, polarization measurement, electron diffraction analysis, infrared multiple reflection spectroscopy and photoelectron spectroscopy in 3%NaCl aqueous solution. The results obtained are as follows: \
oindent(1) Atacamite is formed on surface of copper and copper-zinc alloys. \
oindent(2) On copper-tin alloys, SnO2 layer is formed on the surface of alloys, atacamite and Cu2O are produced on the SnO2 layer. The corrosion resistance of the alloys is due to SnO2 or tin compound layers. \
oindent(3) On copper-aluminium alloys and copper-zinc-aluminium alloys, Cu2O layers are formed, and layers of compound of additional alloying elements are formed on the Cu2O layer. The protective films of these alloys are Cu2O layer. The layer of compound of additional alloying elements affects the growth of the Cu2O layer. The surface compound of the alloys containing Al is mainly AlOOH.
Cu (99.999%) single crystals were grown at a rate of 1 mm/min by the horizontal zone melting technique and the effects of the growth direction the dislocation densrty of the seed crystal and the axial temperature gradient on the formation process of the dislocation subboundaries, particularly the striation boundaries, were examined by the observation of the dislocations by the etch pit method. The results were as follows. The  single crystals showed the most remarkable tendency to develop the striations, but the  and  single crystals were difficult to develop them under normal growth conditions. In the crystal grown under the low axial temperature gradient (20°C/cm), with the low dislocation density seed whose dislocation distribution was homogeneous, the fine network of the subboundaries developed, but the striations did not. On the other hand, in the crystal grown under the same gradient with the seed which contained a fine network of the subboundaries, the striations developed. However, in the high axial temperature gradient (70°C/cm), the striations did not develop, although it was grown with the same seed which developed the striations after growth of one centimeter under a low axial temperature gradient. From the observations of the change of the arrangement of the dislocations and subboundaries along the growth direction of these crystals, it was considered that the striations were formed by the coalescence of the small angle tilted boundaries which were arranged in parallel and closely.
Crystal magnetic anisotropy constant K1 and saturation magnetostriction λs have been measured on the (100) single crystal disk and polycrystal rods of Ni-Mn alloys containing less than about 25%Mn which were heat treated in different ways. The negative values of K1 and λs decreased rapidly with increasing Mn content and changed the sign from minus to plus at about 20%Mn. At compositions lower than about 20%Mn, both values remained almost unchanged with heat treatments. From these results, it may be concluded that the high permeability of Ni-Mn alloys containing about 20%Mn is caused by the very small values of K1 and λs.
Crystal magnetic anisotropy constant K1 and saturation magnetostriction λs have been measured on a single crystal disk of the (100) plane and polycrystal rods of Ni-Mn-Fe alloys containing less than about 29%Mn and about 25%Fe which were cooled at a rate of 26°C/sec from 650°C after heating at high temperature. The absolute value of K1 increases with increasing Fe content and then decreases sligtly after attaining at a maximum. With increasing Mn and Fe contents, the absolute value of λs rapidly decreases and then becomes zero at the composition which contains a little larger amount of Ni than Ni3 (Mn, Fe), after which the value increases gradually. It may be concluded that the high permeability of Ni-Mn-Fe alloys containing about 20%Mn and about 5%Fe is caused by very small values of K1 and λs as in the case of Ni-Mn alloys.
Partial free energy difference ΔGXα⁄γFe is one of the most important parameters to represent the functions of the alloying element in steel. This parameter was defined as the free energy change accompanied by transfer of one mole of each alloying element from ferrite to austenite, and the value has been obtained from α⁄γ equilibrium compositions in the Fe-X system. In the present work, the parameters for various alloying elements were evaluated from the data on Ms and As temperatures of Fe-Ni-X alloys. It was found that the parameter generally changes depending on temperature, especially near the Curie point of iron, and some of the ferrite stabilizing elements, Cr, Mo, W and V act as austenite stabilizers at low temperature. Such a considerable change in the parameter ΔGXα⁄γFe was considered to be mainly due to the magnetic effect suggested by Zener and Hillert et al.
The phase diagram of the Zn-Cu-Mg ternary system in the range of less than Cu 30 wt% and Mg 16 wt% was investigated by means of differential thermal analyses and microscopic examinations. The phase determination was also performed with the aid of EMPA analysis. The results were summarized as follows: (1) A new diagram was obtained in which the Zn-rich corner with compositions up to Cu 5 wt% and Mg 5 wt% was clarified in contrast to the previous diagrams reported by two othre authors. (2) The liquidus surface of the MgZn2 phase was found to exist, which resulted in the occurrence of a ternary peritecto-eutectic reaction. (3) In the range studied, five peritecto-eutectic reactions and one ternary eutectoid reaction were found to take place as follows: (This article is not displayable. Please see full text pdf.)