Physical Analysis of the Creep of Polypropylene and Polyvinylidene Fluoride Threads for Medical Purposes

Fibre Chemistry - Results are given for a study and modelling of short-term creep of polypropylene and polyvinylidene fluoride threads designed for medical purposes. A physical analysis is given...     

Self-Diffusion of Iron in Molten Fe-C Alloys

Self-diffusion coefficients of iron in molten Fe-C alloys have been measured by using the capillary method. In addition, the samples have been autoradiographed and sectioned to insure that no significant convection has occurred during the diffusion. The results can be represented by the equation D = 4.3×10^?3 exp (—12.200/RT) for carbon = 4.6 pct and T = 1513° to 1633°K; and D = 1.0×10^?2 exp (—15,700/RT) for carbon = 2.5 pct and T = 1613° to 1673°K. The D values are higher and the heat of activation for diffusion lower in alloys containing more carbon. Calculation based on the Einstein-Stokes equation indicates that the diffusing species is iron ion.     

Properties of maraging steels after high-temperature treatment

Conclusions For the optimal structure of austenite in maraging steels they should be subjected to rolling with a final rolling temperature not over 900°, rapid heating to Ac₃+30°, and rapid cooling.Institute of Solid State Physics, Academy of Sciences of the USSR. I. P. Bardin Central Scientific-Research Institute of Ferrous Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 31–33, April, 1981.     

Partial Electrode Processes at AC-Polarized Copper in Chloride and Nitrate Media

The dissolution of a copper electrode by passing a rectangular alternating current of an infralow frequency (1/6 Hz) was studied by chronopotentiometric method. The near-electrode concentrations of copper oxidation products were calculated by the numerical solution of the boundary problem of transient diffusion. In concentrated chloride electrolytes, the shape of the E vs. t plot was found to be determined by transient mass transfer. The ratio of the copper reduced during the cathodic half-period to its amount dissolved in the anodic half-period was estimated experimentally. This ratio was used to determine the distribution of faradaic charges between different partial electrode processes. In nitrate electrolytes, cathodic process significantly affects the anodic dissolution of copper.     

Steel Protection from Carbon Dioxide Corrosion with Volatile Inhibitors. II. Vapor Phase

It was shown that the high neutralizing properties and volatilities of some of the inhibitors studied are insufficient to protect steel under these conditions. The inhibitive effect of modified, more hydrophobic aliphatic amines in carbon dioxide under conditions of periodical wetting proved to be enhanced. New inhibitors, namely, amine A and IFKhAN-72, are effective against carbon dioxide corrosion and retain their aftereffects for a long period of time.     

Effect of Heat Treatment and Deformation on the Grain Size and Mechanical Properties of Duralumin-Type Alloys

Mechanical properties and the grain size of alloy D16ch and 1163 used for the sheeting of aircraft fuselages after 21% and 74% deformation and different kinds of heat treatment are studied. The effect of the modes of intermediate, preliminary, and final annealing operations on the grain size is determined. Recommendations are given for providing a small grain size.     

Alloying principles, phase transformations, structure and properties of low-temperature weldable shipbuilding steels

Basic principles for alloying low-temperature shipbuilding steels with yield strength ranging from 235 to 460 MPa are developed. Results of a study of phase transformations including strain-induced ones in the austenitic range are presented. Relations between structure and properties of low-temperature shipbuilding steels subjected to heat and thermomechanical treatment are determined. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 9–15, January, 2007.