Extraordinary damping of Ni-Ti double layer films

An unusually high damping peak has been detected in martensite/martensite d ouble layer Ni-Ti shape memory films. The double layer consisted of two 1-m um thick layers deposited successively at 250 and 385 degreesC from the sam e target onto a 100-mum Si cantilever substrate. Around room temperature, t he individual layers consisted of rhombohedral and monoclinic martensite, r espectively. The maximum damping of the martensite/martensite/Si cantilever , occurring at 50 degreesC, equaled Q(-1) = 1.4 x 10(-4) which corresponds to a damping of the martensite/martensite composite of 11%. It is proposed that this extraordinary damping is caused by the interactive formation of B 19' and R martensites in the stress coupled layers. (C) 2000 Elsevier Scien ce B.V. All rights reserved.