کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5435741 1509535 2017 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Step-controlled Brownian motion of nanosized liquid Pb inclusions in a solid Al matrix
ترجمه فارسی عنوان
حرارتی برونوی گام به گام با استفاده از ماتریکس جامد آلومینیوم شامل مشتقات پلاسمای مایع نانوذرات
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
چکیده انگلیسی

We have made direct observations of the Brownian motion of individual nanosized liquid lead inclusions in solid aluminum by in-situ transmission electron microscopy. The process was found to depend strongly on the size of the inclusion and the anisotropy of the interfacial energy. The rate controlling mechanism was the nucleation of steps on facets of the equilibrium shape and the diffusion of Al along the liquid-solid interface. Because the Al-Pb interface undergoes a roughening transition at Tr ≈ 820 K, the step nucleation barrier decreases with increasing temperature and vanishes completely at Tr. By including the temperature dependence explicitly, we demonstrate that the contribution of the step energy to an Arrhenius plot of the data has a slope greater than the actual activation energy at temperature T by a factor Tr/(Tr -T). In addition, we show that the diffusion barrier for interfacial transport makes a substantial contribution. Our analysis reconciles a large discrepancy between activation energies obtained from the temperature and size dependences of the process and solves the apparent paradox posed by the observation that some particles are frozen in non-equilibrium shapes while nearby smaller particles are sufficiently mobile to undergo rapid Brownian motion.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 141, December 2017, Pages 427-433
نویسندگان
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