by National Aeronautics and Space Administration, George C. Marshall Space Flight Center, For sale by the National Technical Information Service in [Marshall Space Flight Center, Ala.], [Springfield, VA .
Written in English
|Statement||by M.D. Danford.|
|Series||NASA technical memorandum -- NASA TM-100397., NASA technical memorandum -- 100397.|
|Contributions||George C. Marshall Space Flight Center.|
|The Physical Object|
|Pagination||iv, 13 p.|
|Number of Pages||13|
A study for structure and inter-diffusion coefficient of liquid K 1âˆ’x C 5x metal alloys [J]. Physics and Chemistry of Liquids, , 49(6): âˆ’  SUN Wei-hua, ZHANG Li-jun, WEI Ming, DU Yong, HUANG Bai-yun. Effect of liquid diffusion coefficients on microstructure evolution during solidification of Cited by: 1. We propose a model of absorption of hydrogen by titanium alloys in the process of chemical etching. We obtained a solution that describes the amount of absorbed hydrogen and its distribution in the metal as a function of the rate and time of etching. On the basis of the equations obtained, we developed a method for determination of the diffusion coefficient of hydrogen in a : A. V. Fishgoit, T. V. Ivanova. There has been considerable important work to investigate that seems to be a reliable value of diffusion coefficient and temperature dependences of diffusivity in all around alloy and composite because it would be an essential physical constant value in specified materials and vitally useful for material development [1,2].Particularly coefficients for self-diffusion are the most essential and Author: Kazu-masa Yamada, Nobuaki Matsuhashi. alloys is caused by a variation of the diffusion frequency factor due to the corresponding change in the effective energy of the carbon diffusion that is more precisely taken into account in.
Hydrogen permeation and diffusion coefficients in alloys of iron (Fe) and nickel (Ni) with the Ni content of 5, 9, and 20 at.% and a crystal structure of α/α' phase have been examined around. The obtained universal form (valid for binary liquid alloys) is very useful for the estimation of the temperature, composition and pressure dependence of the self-diffusion coefficients. Finally, the relation for the ratio of the impurity and self-diffusion coefficients is : Dezső L. Beke. Diffusion coefficient is the proportionality factor D in Fick's law (see Diffusion) by which the mass of a substance dM diffusing in time dt through the surface dF normal to the diffusion direction is proportional to the concentration gradient grad c of this substance: dM = −D grad c dF dt. Hence, physically, the diffusion coefficient implies that the mass of the substance diffuses through a. Hydrogen diffuses in metals much faster than any other atom. Two different (tracer and chemical) diffusion coefficients are distinguished. Dependent on the host lattice and site occupation diffusion is by nearly classical jumps or by a tunneling mechanism (quantum diffusion).Author: H. R. Schober.
Diffusion Coefficients in Substitutional Alloys For substitutional diffusion in a binary alloy system A-B, the diffusivities of each species, DA and DB are not only a function of temperature, but also of composition. This is largely due to the variation in vacancy concentration, Xv File Size: KB. ingmaterialshavingsmall(oranomalous)temperaturecoefficients. (b) To determinethe effect on thetemperature coefficientsof anneal- ing, coldworking, or temperingthe materials. Permeation, Diffusion, Solubility Measurements: Results and Issues Subject: Research Objectives: To understand the hydrogen transport behavior; Under conditions relevant to hydrogen delivery infrastructure Created Date: 12/11/ PMFile Size: 1MB. The electrochemical permeation technique was used to evaluate the hydrogen diffusion, and analyse its interdependent solubility and trapping behaviour in 9 austenitic stainless steels. The hydrogen diffusion of all alloys obeyed Arrhenius relationships in the temperature range between 25 °C to °C. The apparent diffusion coefficients were determined and the relevant activation energies Cited by: 3.