Laser-stimulated mass transfer in metals

Abstract

Mass transfer in iron and nickel stimulated by pulsed laser radiation is studied by the radioactive isotope method. New experimental results are obtained and an analysis in terms of kinetic equat.ions is given. It is shown: (a) exposure of the metal surface to high intensity pulsed laser radiation leads to an accelerated atomic migration into the sample; (b) an effective retardation, the value of which depends upon the presence of crystalline defects in metals has an esaential influence on the atomic migration rate stimulated by the laser; (c) multiple laser loading results in a concentration maximum formed inside the sample, the depth displacement of which depends upon the energy of light flux and the number of pulsed loadings.

Mass transfer mechanism in real crystals by pulsed laser irradiation

“…The kinetic of a gathering of the tagged atoms 55 F e+ 59 F e, which were penetrated from the surface to bulk of a metal, which was influenced by many-fold pulse laser irradiation (τ ∼ 10 −8 s, W ≈ 0.02J,) was investigated in Armco− F e [25], [29]. A maximum of the concentration of radioactive atoms 55 F e + 59 F e began to be formed after the first three cycles of an irradiation.…”

Model of the impurities redistribution in the surface layer of an alloy under the action of pulsed laser radiation

“…Відомо, що при дії лазерного імпульсу на матеріали прискорюються процеси дифузії атомів з поверхні в матрицю [13][14][15][16]. В роботі [13] це пояснюється захопленням атомів пружнім полем рухомих дислокаційних уступів, що генеруються внаслідок великих градієнтів термічних напружень, а сам процес описується рівнянням дифузії з додатковим членом, який враховує спрямований рух атомів. В роботі [14] теоретично та експериментально встановлено, що перенесення атомів в глибину металу при імпульсній лазерній обробці пов'язано з процесами термопластичної течії матеріалу.…”

Nucleation and Growth in Nanosystems: Some New Concepts

“…If all this extra energy is used for generation of interstitial, their concentration will be m, which appears to be the maximum possible penetration for experiments with shock waves. Yet, authors of the book [58] (and other numerous publications, see, for example, [80][81][82][83]) claim that experimentally the penetration depth can reach as much as 100 microns. If they are right, even direct and total consumption of the shock energy by generation of interstitials cannot be the final explanation.…”

“…[58,59,[80][81][82][83]. Numerous experiments (with tracers as well as with standard diffusion couples) show that such a fast deformation leads to mass transfer with huge penetration depth of max ε is typically about 10-15%).…”