The molten Al and Al alloy containing 5% Cu were cast after various degrees of superheating, under constant conditions of holding duration, agitation at Max. and pouring temperatures, mold, etc.
From the results, it is concluded that the grain size of Al and Al alloy containing 5% Cu is larger, the higher the Max, heating temperature and longer the holding duration at Max. temperatures, in the agitations and agitations with flux, and the grain size is smaller with long holding duration at Pouring temperature.

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By the heat-treatment of silchrome steel, the author obtained various microstructures, such as austenite, martensite, troostite, sorbite and spherical pearlite, and also the corrosibility and passivity formation of these microstructures in sulphuric acid and ferricsulphate solution were studied. By this investigation the critical concentration of ferricsulphate for inducing passivity of these microstructures was determined.

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The re-examination on the process of the temper-hardening of Be-Cu alloys was performed by testing the hardness, microscopic structure and crystalline configuration of these alloys. Furthermore, the measurements of their thermal dilatation and electric resistance were also carried out, together with the thermal analysis.
As one of the consequences of these researches, it was found that the temper-hardening of Be-Cu alloys examined occurs in two steps. By the aids of normal and polarized microscopes, the second step of hardening was confirmed to be due to the formation of the typical γ-precipitation structure, as shown in Photo. 3: While, the first one was considered to be attributed to the dendritic or net-worked structures as reproduced in Photos. 1 and 18 respectively, at the inner portion of the grains, according to the specimens used were polycrystalline aggregates or single crystals crystallized directly from the melt. Here, it is to be noted that the diffraction patterns of X-rays taken with the specimens of the aforesaid two kinds of structures, were always found to consist mainly of a number of radiating bands, as shown in the Laue photographs, Photos. 26 and 37; this indicates without saying the presence of a fibrous-like configuration of micro-crystals. From the experimental results above mentioned, with regard to the first step of hardening, these two kinds of structures were inferred to be formed in consequence of the grain refinement attributable to the precipitation of the intermediate phase, β phase, which had been taken place before any γ-precipitates could be detected.
The foregoing consideration was confirmed again, by comparing it with the results of measurements on the differential dilatation and the electric resistance together with those of the differential thermal analysis. Thus, we may arrive at the following conclusions in connection with the mechanism of the temper-hardening of Be-Cu alloys: (1) Among the two steps of temper-hardening of these alloys, the first one is deemed to be given rise to by the grain refinement, the lattice distortion and the precipitation of the intermediate phase. (2) The second step of hardening is resulted from the precipitation of γ-crystallites and the decomposition of the intermediate phase. (3) The softening phenomenon existing between these two steps, can be attributed to the coagulation of the intermediate phase and the removal of the strain.

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The authors measured the running quality of molten aluminium, and its binary alloys with copper, silicon, zinc, magnesium, manganese or nickel, which is contained within the limit of the industrial addition, by using the same apparatus as used by them on measuring the running quality of molten magnesium and its alloys and obtained the following results:
(1) The running quality of aluminium, whose purity is about 99-5%, slightly decreases at repetitions of remelting and rectilinearly increases with the rise of the superheating temperature up to 100°, but conversely decreases at 1251°
(2) The influences of the simple addition of the alloying element on the running quality of aluminium, about 99.5% Al, are as follows: The running quality of aluminium decreases by an addition of copper up to about 4%, but almost rectilinearly increases by 4% to 33% addition; by an addition of silicon up to about 2% suddenly decreases, but considerably increases by 2 to 15% addition. The modification with metallic sodium and sodium fluoride has no influence on the running quality of 11% Si alloy, but slightly increases it with 13% Si alloy. Zinc up to 3% suddenly decreases the running quality of aluminium from 3% to 10% slightly decreases it and from 10% up to 20% gradually increases it, but no further increase is observable between 20% and, 30%. Magnesium up to about 3% suddenly decreases the running quality of aluminium, but from 3% up to 16% gradually decreases it. Manganese up to 1% slightly decreases it, but 3% to 4% manganese considerably increases and 5% manganese rapidly decreases it again. Nickel up to about 1% suddenly decreases the running quality of aluminium and from 1% to about 5% gradually decreases it. These latter results may be explained by the solidification theory and the equilibrium diagram as on the case of magnesium alloys previously mentioned, excepting the cases of silicon manganese and nickel

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Aluminiumguβes, einige geeignete Fluβmittel, _??_. B. As J₃ ist gewonnen. Dann wir fassetn alles Schriftentum und unsere Versuchsergebnisse zusammen and erreichten als Effekt des Fluβmittels gegen die Poren für jede Al-legierungen einen Schluβ, der in Zahlentafel 9 gezeigt ist.

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In the 2nd report (Nippon Kinzoku Gakkai-si, Vol. 5, No. 2, 1941), the authors reported the effect of the addition of a small amount of metals on the corrosibility of duralumin by measuring the volume change of H₂gas which formed when the specimens were immersed in 10% HCl solution. The present experiments on corrosion-resistance were carried out in 3% NaCl+3% H₂O₂ solution by dip method, mesuring the loss in weight, and also the effect of various elements on intercrystalline corrosion was examined by the microscopic analysis. The results obtained maybe summarised as follows:-
(1) The added elements which improve the corrosion-resistance and intercrystalline corrosion of duralumin, were found to be Cr (<0.3%) and Sb (<0 7%).
(2) The addition of Co, Mo and W gives deleterious effect.
(3) The addition of other elements do not seem to improve the said properties.

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The equilibrium diagram of the magnesium-copper system has been examined by means of thermal and microscopic analyses. The results of the present experiments are summarized as follows:-
(1) In this system there exist two compounds, i.e., Cu₂Mg(β) and Mg₂Cu, which melt at 785° and 567° respectively. By the microscopic examination, the authors has revealed that the compound Cu₂Mg has a solubility range (83.04%_??_82.44% of copper), which Was previously suspected.
(2) There exist three eutectic points as follows:-
(1) The eutectic between the compound Cu₂Mg(β) andd the copper solid solution, occurss at 720° and 91.6% of copper.
(2) The eutectic between the compounds Cu₂Mg(β) and Mg₂.Cu occurs at 550° and 65% of copper.
(3) The eutectic between the compound Mg₂Cu and magnesium side occurs at 488° and 30.8% of copper.
(3) The solubility curve reveals that the solid solubility, of magnesium in copper decreases from about 3.0% at 720° to about 1.5% at 200°

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In the acidic oxidizing solution containing chlorine ion, for example in aqueous solution of ferric chloride, the entire surface of 14% Cr stainless iron or steel corrodes, whereas that of 21%_??_35% Cr stainless iron, being in the passive state, does not corrode at all. When the surface of this high chromium stainless iron comes in contact with non-conductive substances, such as glass, cork or rubber, or noble metals like platinum or gold, a narrow crevice is formed, and the corrosion takes place, making pit or cavity at the point of contact. On 22% Cr, 22%Cr-3%Mo, 22%Cr-7%Mo, and 35% Cr stainless iron, two kinds of specimen, namely those annealed at 900° and those quenched in the water from 1000° or 1300°. were tested in 5% ferric chloride aqueous solution to ascertain whether pit or cavity corrosion takes place by bringing them in contact with non-conductive substances. The mechanism which gives rise to the phenomenon is also discussed. It has been ascertained that while 22% Cr stainless iron is affectfd by the contact, the said effect is greatly reduced when it is alloyed with 3_??_7% molybdenum and quenched in the water, The author discusses briefly the method of prevention of the contact effects based upon the foregoing, experiments

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