Vol. 10, No. 4 (1954)
1954-02-20
CONTENT
1954, 10 (4): 303-320.
doi: 10.7498/aps.10.303
Abstract +
A possible quantum mechanical picture of multiple production of mesons is discussed in the present paper. The theoretical result is in agreement with the experimental evidences. The picture presented in the present paper is different from that given by Fermi. More experimental deta are needed for the comparison of these two theories.
1954, 10 (4): 321-332.
doi: 10.7498/aps.10.321
Abstract +
The formation of σ-phase in a 18% Cr 11% Ni 2.6% Mo 0.8% Ti stainless steel has been investigated. Microscopic and X-ray examinations showed that the formationσf σ-phase from δ-ferrite was accompanied by the formation of austenite, the reaction being most rapid at 850℃The formation of a caused a marked decrease in Izod value and a slight increase in hardness. The σ-phase and its detrimental effects can be removed by a re-solution treatment at 1100℃.
1954, 10 (4): 333-346.
doi: 10.7498/aps.10.333
Abstract +
Impact tests have been carried out on nodular cast iron in -the cast and forged conditions from -85℃ to 1070℃. The results indicate that nodular cast iron of predominantly ferritic matrix possesses two brittle temperature ranges (below 20℃ and between 550 and 700℃), and one comparatively more ductile range (between 850℃ and 1050℃).The fractures and the bending of the specimens at fracture have also been examined, and these have been correlated to the changes in structure of the matrix in the discussion.Finally, a brief account has been made of the possible applications of the results in the present research in evaluating the applicability of nodular cast iron at various temperatures; and, in particular, in the choice of proper hot working temperatures of this new material. The best hot working temperatures as indicated by the present results have been confirmed by actual forging and upsetting tests under the pneumatic and drop hammers respectively.
1954, 10 (4): 347-364.
doi: 10.7498/aps.10.347
Abstract +
A spectrographic procedure for determining copper in concentrated iron ores has been worked out for routine analysis. The powder method is found to be satisfactory with a medium quartz spectrograph and an activated a. c. arc between carbon electrodes as light source. In order to minimize erratic burning of the sample, the electrodes are pre-burned for one minute and then loaded with a mixture of equal weight of the ore sample and carbon powder. The analysis pair of lines chosen are: Cu 2824.369 Fe 2824.67 for copper contents ranging from 0.05 to 0.3%, and Cu 2824369- Fe 2828.813 for those between 0.3 and 1.0%. The results obtained spectrographically have been checked by wet chemical analysis, amongst 110 samples 80% of which the two methods checked within 0.02%.
1954, 10 (4): 365-382.
doi: 10.7498/aps.10.365
Abstract +
Creep under very small torsional stress has been investigated for 99.95% polycrystalline iron in the temperature range of 350°-525℃. The general features of the creep curves obtained are essentially the same as those previously reported for 99.991% aluminum. The creep is shown to be consisted of two parts, one occurring at lower temperatures or shorter times and the other at higher temperatures or longer times. The first part of the creep is limited in extent and is associated with the viscous behavior of grain boundaries. The activation energy for this grain-boundary creep is 78,000 ± 4,000 calories per mole according to the present creep and stress relaxation measurements. This value is close to the activation energy for self-diffusion of iron, a correlation which indicates that, in so far as to the mechanism of atomic migration is concerned, grain boundaries may not be very different from the interior of the grains.Both parts of the creep are noticably lessened by the addition of carbon in the iron specimen. A striking feature is that the viscous slip along grain boundaries appears to be hindered by carbon at a concentration as low as 0.0004%. These observations provide a guiding clue as to the problem of controlling high-temperature creep of metals and render further experimental support on the hole model previously suggested for the grain boundaries.With regard to the second part of the creep, it is tentatively suggested that its mechanism may be connected with atomic rearrangements of holes inside the grains.
1954, 10 (4): 395-412.
doi: 10.7498/aps.10.395
Abstract +
Non-linear differential equations have been developed for the calculation of the deflections and buckling loads of Sandwich plates subjected to transverse loads and edgewise shears and compressions.The Sandwich plate consists of two thin metal face sheets bonded to a light slab-the core. The core is taken to have zero moduli as deformations in its own plane. This appears to give an adequate representation of behavior of many core materials.Some previous theories are shown to be special cases of this more general theory. The essence of non-linearity are shown through the dicussian of core properties and action of interface-and-core forces. The restriction of some special forms of displacements of practical interest has been studied and the existence of nonlinear element in the bending problem is clarified. The relative merit of using large bending deflection theory instead of the small bending deflection theory in the faces is given.
