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Wednesday, December 5, 2007 - 11:40 AM
29.3

Effect of Texture on Internal Friction of Ti-24mol%Nb-3mol%Al Shape Memory Alloy

T. Inamura, K. Wakashima, H. Hosoda, Tokyo Institute of Technology, Yokohama, Japan; Y. Yamamoto, Graduate student, Tokyo Institute of Technology, Yokohama, Japan; H. Y. Kim, S. Miyazaki, University of Tsukuba, Tsukuba, Japan

Internal friction (IF) of a Ti-base shape memory alloy, Ti-24mol%Nb-3mol%Al, with a well developed texture was investigated in terms of the crystallography of the transformation.  {112}<110> recrystallization texture was well developed in the alloy by a thermomechanical treatment.  The measurement was made by a dynamic mechanical analyzer (DMA) in a tensile mode with a frequency range of 1~50Hz.  Heating/cooling rate was 3K/min and the temperature range was 123K~423K to include the martensitic transformation temperature.  IF due to the motion of both martensite/parent and martensite/martensite interfaces were measured as a function of temperature along several loading directions under several stress-amplitude and frequencies.  There were two IF-peaks corresponding to the motion of martensite/parent and martensite/martensite interfaces.  Relationship between IF-peak height and eigenstrain is discussed on the viewpoint of the crystallography of the transformation and the re-arrangement of variants.

Summary: Internal friction (IF) of a Ti-base shape memory alloy, Ti-24mol%Nb-3mol%Al, with a well developed texture was investigated in terms of the crystallography of the transformation. {112}<110> Internal friction (IF) of a Ti-base shape memory alloy, Ti-24mol%Nb-3mol%Al, with a well developed texture was investigated in terms of the crystallography of the transformation. {112}<110> recrystallization texture was well developed in the alloy by a thermomechanical treatment. The measurement was made by a dynamic mechanical analyzer (DMA) in a tensile mode with a frequency range of 1~50Hz. Heating/cooling rate was 3K/min and the temperature range was 123K~423K to include the martensitic transformation temperature (Ms). IF due to the motion of both martensite/parent and martensite/martensite interfaces were measured as a function of temperature along several loading directions under several stress-amplitude and frequencies. There were two IF-peaks corresponding to the motion of martensite/parent and martensite/martensite interfaces. Relationship between IF-peak height and Eigen- strain is discussed on the viewpoint of the crystallography of the transformation and the re-arrangement of variants. texture was well developed in the alloy by a thermomechanical treatment. The measurement was made by a dynamic mechanical analyzer (DMA) in a tensile mode with a frequency range of 1~50Hz. Heating/cooling rate was 3K/min and the temperature range was 123K~423K to include the martensitic transformation temperature (Ms). IF due to the motion of both martensite/parent and martensite/martensite interfaces were measured as a function of temperature along several loading directions under several stress-amplitude and frequencies. There were two IF-peaks corresponding to the motion of martensite/parent and martensite/martensite interfaces. Relationship between IF-peak height and Eigen- strain is discussed on the viewpoint of the crystallography of the transformation and the re-arrangement of variants.