Quantitative Study of Strain-Enhanced Atomic Transport in Mechanically Milled Metal Powders

点击翻译按钮获取中文摘要

9500617 Atzmon A quantitative study is made of the temporal evolution of structural and microstructural parameters of metal powders during ball milling. A ball mill design is employed which allows precise knowledge and control of the powder temperature, milling intensity and atmosphere with the temperature and milling intensity as main control variables. Materials parameters of interest include grain size, root-mean-square elastic strain, long- and short-range order parameters, solubilities in supersaturated solutions, domain sizes in two-phase mixtures, and the crystallized fraction in amorphous alloys. Characterization of the material is by x-ray diffraction, differential scanning calorimetry, and scanning and transmission electron microscopy. Elaborate analysis of experimental results should provide expressions for the contributions of plastic deformation and thermal recovery to the evolution of each parameter. The results are interpreted in analogy with theories of radiation-enhanced diffusion and radiation-induced phase formation. Most importantly, quantitative evidence for plastic deformation enhanced diffusion is expected to be obtained from the thermal recovery term. %%% This work is expected to provide new and quantitative understanding of microscopic processes occurring during ball milling. It is anticipated that the experience gained in systematic microstructural design will help in prospective practical applications. ***