Dynamic Micro-Strain Analysis of Ultrafine-Grained Aluminum Magnesium Alloy Using Digital Image Correlation
Abstract
Tensile tests were performed in situ on an ultrafine-grained (UFG) Al-Mg alloy using a micro-tensile module in a scanning electron microscope. The micro-strain evolution was tracked and measured using digital image correlation (DIC). A fine random speckle pattern was required to achieve high resolution and accuracy of strain measurement using DIC. To produce the speckle pattern, a patterning method was developed using electron beam lithography to deposit a gold speckle pattern. The nanoscale feature size of this gold pattern (45 nm) was useful for identifying the micro-strain among individual grains of the UFG Al-Mg alloy. Microstructural aspects of the UFG Al-Mg alloy were revealed by analysis of electron backscattered diffraction (EBSD) patterns. Finally, the effect of the UFG Al-Mg alloy microstructure on the nanoscale deformation mechanism was investigated by combining EBSD and DIC data in a contour map. This combined technique provides a method for direct measurement of micro-strain and is potentially useful for deformation studies of a wide range of nanostructured materials.
- Publication:
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Metallurgical and Materials Transactions A
- Pub Date:
- January 2014
- DOI:
- 10.1007/s11661-013-1805-9
- Bibcode:
- 2014MMTA...45...47Z
- Keywords:
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- PMMA;
- Digital Image Correlation;
- Speckle Pattern;
- Image Distortion;
- Confidence Index