Factors affecting reversible shape-memory
In the last twenty years Reversible Shape-Memory (RSM) alloys have become the source of considerable technological interest as a result of their ability to generate spontaneous and reversible changes of shape on thermal cycling. This has led to the development of a range of reversible shape-memory d...
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ndltd-bl.uk-oai-ethos.bl.uk-3545162018-09-11T03:17:53ZFactors affecting reversible shape-memoryFriend, C. M.1985In the last twenty years Reversible Shape-Memory (RSM) alloys have become the source of considerable technological interest as a result of their ability to generate spontaneous and reversible changes of shape on thermal cycling. This has led to the development of a range of reversible shape-memory devices for thermostatic sensing applications. In these devices the alloy is subjected to several thousand shape-memory cycles and the stability of the reversible shape-memory is therefore an important alloy property. Data on the effect of shape-memory cycling on the long-term stability of the reversible shape-memory, however, is extremely limited. The present work, conducted to fill this gap, has shown that there is an inherent instability in the reversible shape-memory, with changes in the operating temperatures and cumulative reductions in the maximum shape-strain output of actuators on long-term thermal cycling under conditions simulating real devices. Extensive investigation has shown that these instabilities result from a number of sources, ageing of the shape-memory martensites and most importantly from morphological disruptions in the "trained" martensites caused by two-stage stress-induced transformation and due to the build-up of transformation-induced dislocation debris. This shape-strain degradation has also been successfully modelled by means of a simple two-stage stress-induced martensitic transformation model.669Reversible Shape-Memory alloysUniversity of Surreyhttps://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354516http://epubs.surrey.ac.uk/847449/Electronic Thesis or Dissertation |
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669 Reversible Shape-Memory alloys |
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669 Reversible Shape-Memory alloys Friend, C. M. Factors affecting reversible shape-memory |
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In the last twenty years Reversible Shape-Memory (RSM) alloys have become the source of considerable technological interest as a result of their ability to generate spontaneous and reversible changes of shape on thermal cycling. This has led to the development of a range of reversible shape-memory devices for thermostatic sensing applications. In these devices the alloy is subjected to several thousand shape-memory cycles and the stability of the reversible shape-memory is therefore an important alloy property. Data on the effect of shape-memory cycling on the long-term stability of the reversible shape-memory, however, is extremely limited. The present work, conducted to fill this gap, has shown that there is an inherent instability in the reversible shape-memory, with changes in the operating temperatures and cumulative reductions in the maximum shape-strain output of actuators on long-term thermal cycling under conditions simulating real devices. Extensive investigation has shown that these instabilities result from a number of sources, ageing of the shape-memory martensites and most importantly from morphological disruptions in the "trained" martensites caused by two-stage stress-induced transformation and due to the build-up of transformation-induced dislocation debris. This shape-strain degradation has also been successfully modelled by means of a simple two-stage stress-induced martensitic transformation model. |
author |
Friend, C. M. |
author_facet |
Friend, C. M. |
author_sort |
Friend, C. M. |
title |
Factors affecting reversible shape-memory |
title_short |
Factors affecting reversible shape-memory |
title_full |
Factors affecting reversible shape-memory |
title_fullStr |
Factors affecting reversible shape-memory |
title_full_unstemmed |
Factors affecting reversible shape-memory |
title_sort |
factors affecting reversible shape-memory |
publisher |
University of Surrey |
publishDate |
1985 |
url |
https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354516 |
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AT friendcm factorsaffectingreversibleshapememory |
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1718732268489408512 |