Quantitative determination of strain fields around Ni₄Ti₃ precipitates in NiTi

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• 作者：Tirry ; W. ; Schryvers ; D.
• 关键词：Ni₄Ti₃ precipitation ; NiTi ; HREM ; Strain field ; Eshelby model
• 刊名：Acta Materialia
• 出版年：2005
• 期刊代码：1_13596454
• 类别：ms
• 出版时间：February, 2005
• 卷：53
• 期：4
• 页码：1041-1049
• 文件大小：551 K

摘要

High-resolution transmission electron microscopy and image-processing techniques are used to measure the strain fields surrounding coherent Ni₄Ti₃ precipitates in an austenitic Ni₅₁Ti₄₉ matrix. Images are recorded in the [11 Formula Not Shown ]_B2 and the [10 Formula Not Shown ]_B2 zones, and the {110}_B2 interplanar spacings are used to determine the strain induced by both small (50 nm diameter) and large (300 nm diameter) precipitates. From these observations, the maximum strain in the surrounding matrix is mapped and identified as compressive or tensile. Interactions between strain fields of different precipitates are also investigated. A simple model for the observed strain is proposed and compared to the classical Eshelby solution for an ellipsoidal inclusion.