https://scholars.lib.ntu.edu.tw/handle/123456789/597897
Title: | On the decrease in transformation stress in a bicrystal cu-al-mn shape-memory alloy during cyclic compressive deformation | Authors: | Su T.-H Lu N.-H Chen C.-H CHUIN-SHAN CHEN CHIH-HSUAN CHEN |
Keywords: | Data-driven identification;Digital image correlation;Full-field stress and strain measurements;Functional fatigue;Shape memory alloys;Superelasticity;Bicrystals;Copper alloys;Crystal orientation;Grain boundaries;Metadata;Strain;Stress analysis;Compressive deformations;Cu-based shape memory alloy;Digital image correlations;Functional performance;Inhomogeneous distribution;Martensite transformations;Stable transformation;Transformation stress;Shape-memory alloy | Issue Date: | 2021 | Journal Volume: | 14 | Journal Issue: | 16 | Source: | Materials | Abstract: | The evolution of the inhomogeneous distribution of the transformation stress (σs ) and strain fields with an increasing number of cycles in two differently orientated grains is investigated for the first time using a combined technique of digital image correlation and data-driven identification. The theoretical transformation strains (εT) of these two grains with crystal orientations [5 3 26]β and [6 5 11]β along the loading direction are 10.1% and 7.1%, respectively. The grain with lower εT has a higher σs initially and a faster decrease in σs compared with the grain with higher εT . The results show that the grains with higher σs might trigger more dislocations during the martensite transformation, and thus result in greater residual strain and a larger decrease in σs during subsequent cycles. Grain boundary kinking in bicrystal induces an additional decrease in transformation stress. We conclude that a grain with crystal orientation that has high transformation strain and low transformation stress (with respect to loading direction) will exhibit stable transformation stress, and thus lead to higher functional performance in Cu-based shape memory alloys. ? 2021 by the authors. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85112261279&doi=10.3390%2fma14164439&partnerID=40&md5=c00ab899b63d0d9baa492db9e8fa34c3 https://scholars.lib.ntu.edu.tw/handle/123456789/597897 |
ISSN: | 19961944 | DOI: | 10.3390/ma14164439 |
Appears in Collections: | 土木工程學系 |
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