Title: | Studies on polymeric composites with Ni-Mn-Ga alloys and carbon nanotubes |
Author(s): | Lahelin, Mika |
Date: | 2011 |
Language: | en |
Pages: | Verkkokirja (5800 KB, 68 s.) |
Department: | Biotekniikan ja kemian tekniikan laitos Department of Biotechnology and Chemical Technology |
ISBN: | 978-952-60-4388-3 (PDF) 978-952-60-4387-6 (printed) |
Series: | Aalto University publication series DOCTORAL DISSERTATIONS , 126/2011 |
ISSN: | 1799-4942 |
Supervising professor(s): | Seppälä, Jukka, Prof. |
Thesis advisor(s): | Seppälä, Jukka, Prof. |
Subject: | Materials science, Metallurgy |
Keywords: | composite, Ni-Mn-Ga, damping, carbon nanotubes, dispersion, DMA |
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Abstract:In the first part of the study, the temperature and stress dependencies on the damping of bulk Ni-Mn-Ga alloys were studied. The measurements showed a significant decrease in the storage modulus values in martensite region for all alloys with an increasing temperature. The loss modulus values were almost constant in the martensite phase, decreasing to ∼ zero at the martensite to austenite transformation. The damping of bulk Ni-Mn-Ga decreased sharply at the transformation temperature. The stress dependency on the damping was measured for a non-modulated Ni-Mn-Ga alloy, showing a certain level of stress, twinning stress, which must be overcome before the twins in an Ni-Mn-Ga alloy can begin to move, and the damping due to the twin movement can be activated.
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Parts:[Publication 1]: I. Aaltio, M. Lahelin, O. Söderberg, O. Heczko, B. Löfgren, Y. Ge, J. Seppälä, and S.-P. Hannula. 2008. Temperature dependence of the damping properties of Ni–Mn–Ga alloys. Materials Science and Engineering A, volumes 481-482, pages 314-317. © 2007 Elsevier. By permission.[Publication 2]: I. Aaltio, K. P. Mohanchandra, O. Heczko, M. Lahelin, Y. Ge, G. P. Carman, O. Söderberg, B. Löfgren, J. Seppälä, and S.-P. Hannula. 2008. Temperature dependence of mechanical damping in Ni–Mn–Ga austenite and non-modulated martensite. Scripta Materialia, volume 59, number 5, pages 550-553. © 2008 Acta Materialia. By permission.[Publication 3]: M. Lahelin, I. Aaltio, O. Heczko, O. Söderberg, Y. Ge, B. Löfgren, S.-P. Hannula, and J. Seppälä. 2009. DMA testing of Ni–Mn–Ga/polymer composites. Composites Part A: Applied Science and Manufacturing, volume 40, number 2, pages 125-129. © 2008 Elsevier. By permission.[Publication 4]: M. Lahelin, M. Annala, A. Nykänen, J. Ruokolainen, and J. Seppälä. 2011. In situ polymerized nanocomposites: Polystyrene/CNT and Poly(methyl methacrylate)/CNT composites. Composites Science and Technology, volume 71, number 6, pages 900-907. © 2011 Elsevier. By permission.[Publication 5]: M. Lahelin, A. Vesterinen, A. Nykänen, J. Ruokolainen, and J. Seppälä. 2011. In situ polymerization of methyl methacrylate/multi-walled carbon nanotube composites using cationic stearyl methacrylate copolymers as dispersants. European Polymer Journal, volume 47, number 5, pages 873-881. © 2011 Elsevier. By permission.[Publication 6]: Minna Annala, Mika Lahelin, and Jukka Seppälä. Utilization of PMMA-CNT and PS-CNT in situ polymerized composites as masterbatches for melt mixing. Submitted. |
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