A series of corrosion tests of Fe-Ni-Cu alloys containing 50%, 60%, 70% and 90% Ni with varying Cu content 1.00-10.09% and a trace of carbon, were carried out by the dip method. The corrosion was examined in 10% aqueous solutions of HNO₃, HCl and H₂SO₄ at 25° by measuring the loss in weight, and the extent of corrosion was expressed as mg/cm² hour. The results were discussed by referring equilibrium diagram of the Fe-Ni-Cu system.

View full abstract

Alloys of β phase of the Cu-Sb system were quenched and tempered and the changes in their structure were examined by means of microscopic, differential dilatometric, and X-ray analyses. The following conclusions were drawn: (1) The number of atoms in the unit cell of β phase is 14 in the atomic ratio of 10 Cu and 4 Sb. (2) By rapid cooling of β phase an intermediate phase β's formed which precipitates on tempering, at first, δ phase (expansion) then θ phase (contraction) and finally decomposes into δ and θ phases at 280_??_300°. (3) This change β'→δ+θ also appears in cast specimens. (4) Alloys of 55.5_??_63.5% Cu quenched from β field have a facecentered tetragonal lattice with a=5.66_??_5.89Å, c=5.94_??_6.08Å, c/a=1.007_??_1.07, but those of 63.5_??_68% Cu have a cubic lattice with a=5.91_??_5.928Å or, by tempering, a face-centered tetragonal lattice with a=5.94_??_5.97Å, c=5.80_??_5.88Å, c/a=0.972_??_0.990. (5) The cubic lattice of the β' phase interchanges the axes of a and c at about the eutectoid composition (63.5%Cu). (6) By ageing of quenched β alloys, the ratio of c/a increases in alloys rich in θ phase, but decreases in alloys rich in δ phase.

View full abstract

F. S. (Fixed Stress) Typed Hysterograph is a torsion fatigue testing machine newly designed by the present writer. It is designed to be measurable the stress-strain diagram of the test piece which is stressed and vibrated by the speed of n=1, 900 rev/min. The mechanism of the hysterograph is very simple as shown in Fig. 1; it composes of the two plane mirrors m₁ & m₂ inclined both 45° to the axis and to each other. A point light reflected twice by the mirrors, describes on a plate glass the hysteresis loop of the test piece. The change in hysteresis loop of the test piece in the course of fatigue test is able to measure by this hysterograph. The accuracy of this apparatus is as follows: the hysteresis loop begins to appear when the plastic angle of twist θ=1' is introduced in the stress cycle. The mean stress τ_m=(τ₀+τ_u)/2 is applicable by this machine besides the ordinary vibration ±τ stress. Duralumin, quenched and annealed, and Ni-Cr-W steel were tested. The results are shown in the fatigue diagrams in Figs. 6 and 12. Figs. 7 and 8 show the process of change of the hysteresis loops of duralumin, in which case hysteresis losses increase by fatigue. But Ni-Cr-W steel by this test fatigues and breaks under no hysteresis losses, as shown in Fig. 11. In the Ni-Cr-W steel, the test piece yields some permanent set θ_set, even in the fatigue limit, when the upperlimit-stress τ₀ overcomes the elastic limit, in the case of mean stress applied. Fig. 16 shows the relation of permanent set between fatigue tests and static test. By these tests it is concluded that the θ_set of fatigue test is about half of the static. The fatigue limit, hysteresis loop and permanent set are measurable by our hysterograph.

View full abstract

(1) The relation curve of the volume change during solidification and composition of the Pb-Bi system is more complex in the alloy range which has the peritectic reaction than that of the simple eutectic type system, and the relation between the volume shrinkage by peritectic reaction and composition is the straight line.
(2) The volume shrinkage during solidification of the Pb-Bi system is larger than the calculated value by the mixture rule. This is attributed to the fact that the specific volume is smaller in the solid state but larger in the liquid state than calculated value by the mixture rule.
Hence by adding corrected values to the calculated value, the latter was found to be in good agreement with the former.
(3) The relation between the volume shrinkage and composition in the Sn-Cd system resemble to that of the simple eutectic type system, but, there is no max. point at the composition of max. solidification interval, because the specific volume is larger than the calculated value by the mixture rule. By adding similarly the corrected value to the calculated value, the calculated and observed values were found to be in good agreement.

View full abstract

(1) The specific volume change during solidification of the elements and the atomic number can be shown by periodic relation.
(2) It is very interesting to note that in the second-fifth periods of the Periodic Table, there exist elements which expand during solidification, such as Si, Ga, Sb and Bi; the expansion of Si has been found by the present author.
(3) The volume changes during solidification of five compounds, Zn₄Sb₃ (Zn 41.72%) Zn₃Sb₂ (Zn 44.61%) Mg₂Sn (Sn 70.93%) MgZn (Zn 84.32%) and CuAl₂ (Cu 54.10%) have been measured. It has been found that the compounds Zn₄Sb₃, Zn₃Sb₂ and Mg₂Sn expand for 1.76% 1.65% and 0.70% respectively, while the compounds MgZn₂ and CuAl₂ shrink for 23.76% and 3.12% respectively, the shrinkage of MgZn₂ being very much largar than that of the other metals, these results do not agree with the calculated values by the mixture rule, this may bear an interesting property of the metallic compound.
(4) The specific volumes in the liquid and solid states of the Zn-Sb system are very much larger than the calculated values by the mixture rule, but by calculating the volume changes of compounds of the Zn-Sb system during solidification as in the case of the previous calculation in the Pb-Bi system, the calculated values agree well with the observed values. From this result. it seems that the abnormal volume changes of Mg₂Sn and MgZn₂ are due to difference in specific volumes between the liquid and solid states trom the calculated values.
(5) The volume shrincages of η (Cu₃Sn, Cu 61.64%) and δ (Cu₃₁Sn₈, Cu 67.50%) compounds of the Cu-Sn system during formation from the β solid soltion have been measured. The shrinkage of Cu₃Sn (1.19%) and δ (0.43%) is very large for the volume change of the solid phase and δ has an important relation with the casting of the gunmetal.

View full abstract

Some 55 copper alloys, containing Nickel and Silicon varying up to 5 percent. by weight of each metal, were cast and rolled into rods, and then, the effect of composition on the hot or cold working and the relation between composition and aging capacity by heat-treatments were investigated. The microstractures of several alloys after heat-treatments were also examined. These experimental results showed that Coper alloys containing nickel and silicon in the approximate ratio of 4:1 have Opptimum aging capacity, e. i. maximum in electrical conductivity and hardness.

View full abstract

For the synopsis of this work see the Report I [This journal, 2 (1938), 619]

View full abstract

[in Japanese]

View full abstract