Measurement of Annealing Phenomena in High Purity Metals with Near-field High Energy X-ray Diffraction Microscopy
Measurement of Annealing Phenomena in High Purity Metals with Near-field High Energy X-ray Diffraction Microscopy
复制标题
用近场高能 X 射线衍射显微镜测量高纯金属的退火现象
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
C. Hefferan
中科院分区：
文献类型：
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作者：
C. Hefferan
用于近场高能X射线衍射显微镜(NfHEDM)分析的正演模拟方法(FMM)已成为材料表征的有力工具，能够无损地测量材料内部的微结构。NfHEDM是一种基于同步加速器的技术，它使用高分辨率相机拍摄多晶体的X射线衍射图像。衍射信号被用来重建具有高方向性和空间分辨率的二维图形式的颗粒系综，并可以通过连续测量扩展到体积测量。这项技术的特点是能够监测同一组谷物对外部刺激的反应。本论文将研究显微组织对退火的响应。用两个高纯金属丝样品观察到回复、再结晶和晶粒长大三种热激活现象。对铝进行的第一次测量表明，在回复和再结晶过程中，变形的微观组织被有序的晶粒所取代。对完全再结晶的镍样品进行的晶粒生长测量表明，它对许多面心立方金属常见的低能晶界的演化很敏感。
The forward modeling method (FMM) for analysis of near-field High Energy X-ray Diffraction Microscopy (nfHEDM) has emerged as a powerful tool for materials characterization, with the ability to non-destructively measure microstructures deep within the bulk of materials. A synchrotron based technique, nfHEDM images X-ray diffraction from polycrystals with high resolution cameras. The diffraction signal is used to reconstruct the ensemble of grains in the form of 2D maps with high orientation and spatial resolution, and can be extended to volumetric measurements through sequential measurement. The hallmark of this technique is the ability to monitor the same ensemble of grains as they evolve in response to an external stimuli. This thesis will investigate the response of microstructure to annealing. The three thermally activated phenomena of recovery, recrystallization, and grain growth will be observed with two high purity metal wire samples. The first measurement, performed on aluminum, demonstrates the replacement of a deformed microstructure with well ordered grains in the recovery and recrystallization processes. A grain growth measurement performed on a fully recrystallized nickel sample demonstrates sensitivity to the evolution of a population of low energy grain boundaries, common to many fcc metals.