微纳尺度结构定量表征在铝合金设计和制造知识系统中的作用及进展

发布时间：2018-06-02 06:09

本文选题：析出相 + 晶体结构　；参考：《中国材料进展》2017年06期

【摘要】：材料基因工程是铝合金实现高效设计的必经途径,而定量结构表征是铝合金设计和制造知识系统中关于微结构模拟及其控制的不可或缺的输入及验证。对铝合金而言,定量的微纳尺度结构表征包括精准的物相晶体结构鉴定、成分测定等,以及在此基础上进行的物相尺寸、数密度及体积分数等关键结构参数的精准测量。以Al-Mg-Si(-Cu)合金为例,综述了系列表征技术在铝合金微纳结构定量表征中的应用。首先,指出高分辨透射电子显微术、高角环形暗场及环形明场扫描透射电子显微术等技术对研究铝合金中常见的纳米析出相的原子尺度结构有明显的优势,但是也存在电子束损伤高的风险;三维原子探针尤其适合对原子团簇及纳米析出相进行精准的成分测定,但也存在样品小、破坏性检测、无法达到原子分辨率的问题;而选区电子衍射等传统技术则正好与之互补,同时低电压、低剂量率的高分辨TEM观察也是未来值得努力的方向之一。其次,介绍了最近发展起来的一种主要基于传统的会聚束电子衍射来测量纳米析出相体积分数的精准易行的方法。最后,指出在未来研究中,结合前述纳米至原子尺度结构表征手段以及聚焦离子束连续切片法、电子全息照相术、X射线纳米全息照相术等微米-纳米之间尺度的表征手段对铝合金实现多过程、跨尺度定量结构表征的意义,并指出基于原位加热TEM观察来实现动态结构表征是未来的重要发展方向之一。
[Abstract]:Material genetic engineering is a necessary way to realize high efficiency design of aluminum alloy. Quantitative structural characterization is an indispensable input and verification of microstructure simulation and control in aluminum alloy design and manufacturing knowledge system. For aluminum alloys, quantitative characterization of micro- and nanoscale structures includes accurate identification of phase crystal structure, determination of composition, and accurate measurement of key structural parameters such as phase size, number density and volume fraction. Taking Al-Mg-Si-Cu) alloy as an example, the application of a series of characterization techniques in quantitative characterization of Al-Mg-Si-Cu alloy was reviewed. Firstly, it is pointed out that the techniques of high resolution transmission electron microscopy, high angle ring dark field and ring open field scanning transmission electron microscopy have obvious advantages in studying the atom-scale structures of the common nano-precipitated phases in aluminum alloys. However, there is also the risk of high electron beam damage. Three-dimensional atomic probe is especially suitable for accurate determination of atomic clusters and nano-precipitates, but there are also the problems of small sample size and destructive detection, which can not achieve atomic resolution. Traditional techniques, such as selective electron diffraction, complement each other, and high resolution TEM observation with low voltage and low dose rate is one of the promising directions in the future. Secondly, a recently developed method for measuring the volume fraction of nanocrystalline precipitates based on conventional convergent beam electron diffraction is introduced. Finally, it is pointed out that in the future research, the method of characterization of nano- to atom-scale structures and the focused ion beam continuous slice method are used. Electron holography and X-ray nanoscale holography and other means of characterization between micron and nanometer scales are of significance for the quantitative characterization of aluminum alloys by means of multi-process and cross-scale quantification. It is pointed out that dynamic structure characterization based on in-situ heating TEM observation is one of the important development directions in the future.
【作者单位】：中南大学粉末冶金国家重点实验室中德铝合金微结构联合实验室;中铝科学技术研究院有限公司;中南大学材料科学与工程学院;
【基金】：国家自然科学基金资助项目(51501230,51531009) 中国博士后基金面上项目(2016M600634)
【分类号】：TG146.21

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