ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
The ductility of Cu – Al – Mn shape memory alloys at room temperature depends on thealuminium content. High aluminium contents make Cu – Al – Mn very brittle and unsuitable forplastic shaping. Two Cu – Al – Mn shape memory alloys were investigated. The ductile alloyCuAl7.8Mn9.5 (all contents in wt. %) could be easily cold rolled by 86 %. The alloy CuAl12Mn4.3could be cold rolled by only 12 - 14 %. The amplitude dependence of damping of austeniticspecimens increased with increasing degree of cold work, whereas the damping of martensiticausteniticspecimens decreased. These observations can be explained by the creation of stressinduced martensite and therefore by new moveable interfaces like phase- and twin boundaries,which contribute to damping. Plastic deformation increases the dislocation density, too. Both theincrease of dislocation density and the increase of martensite content can lead to a decrease ofdamping mainly for high deformation degrees. Same shape memory alloys have shown negligiblehardness increase during cold rolling, too. This behaviour, untypical for metals, can be explained bythe generation of new martensite and by the fact that the hardness of martensite is smaller than thehardness of austenite. Some aging effects of the specimen after cold rolling, which lead to decreaseof damping, were detected. This can be explained by pinning of moveable interfaces by pointdefects and/or retransformation of martensite into austenite
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.137.155.pdf
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