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

9500617 Atzmon对球磨过程中金属粉末的结构和微观结构参数的时间演变进行了定量研究。采用球磨机设计，其允许精确地了解和控制粉末温度、研磨强度和气氛，其中温度和研磨强度作为主要控制变量。 感兴趣的材料参数包括晶粒尺寸，均方根弹性应变，长和短范围的顺序参数，在过饱和溶液中的溶解度，在两相混合物中的域尺寸，和非晶合金中的结晶分数。 该材料的表征是通过X射线衍射，差示扫描量热法，扫描和透射电子显微镜。 对实验结果的详细分析应提供塑性变形和热恢复对每个参数演变的贡献的表达式。 与辐射增强扩散和辐射诱导相形成的理论类比的结果进行解释。 最重要的是，预计将从热恢复期获得塑性变形增强扩散的定量证据。这项工作预计将提供新的和定量的理解球磨过程中发生的微观过程。 预计在系统的微观结构设计中获得的经验将有助于未来的实际应用。***

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. ***