ISSN:
1662-0356
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Natural Sciences in General
,
Technology
Notes:
Due to the complex microstructure and phase transformations taking place in ShapeMemory Alloys (SMA), the behaviour and properties of these materials are deeply influenced bytheir loading history in terms of stress, strain and temperature. Indeed, a thorough understanding ofthe effects of the loading history on SMA properties is fundamental for a correct modelling anddesign of SMA applications, in particular in the case of complex loading. An example are shapememory alloys embedded in composite systems, in which stress, strain and temperature varysimultaneously depending upon the properties of the SMA and composite. This work presents thefirst results of an experimental investigation on the effects of the loading history on SMAtransformation temperatures. Nitinol wires of untrained material were considered. Specimensconsisting of Martensite and R-phase were subjected to different loading histories, keeping in turnstress, strain or temperature at a constant value. Transformation temperatures at zero stress of thesesamples were measured via Differential Scanning Calorimetry. Contrarily to most constitutivemodels assumptions, the DSC results highlight a dependence of the transformation temperatures onthe loading history, influencing in particular the Martensite to Austenite phase transformation
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/42/transtech_doi~10.4028%252Fwww.scientific.net%252FAST.59.57.pdf
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