三元Ti_(49.2)Ni_(49.3)Co_(1.5)形状记忆合金的低频阻尼特性

Research on Damping Characteristics of Ternary Ti_(49.2)Ni_(49.3)Co_(1.5)Shape Memory Alloy

用动态机械热分析仪在变频、变温、变振幅条件下 ,对三元Ti4 9.2 Ni4 9.3Co1.5合金的低频阻尼特性进行了研究 ,结果表明 :三元Ti4 9.2 Ni4 9.3No1.5合金由于温度和应力的作用发生相变而导致不同的阻尼特性 ,马氏体相 (M )、R相的阻尼高于母相(P) ,相变过程 (多相共存 )出现阻尼峰 (极大值 ) ,同时伴随有对应的弹性模量峰 (极小值 ) ;频率和振幅对相变阻尼及马氏体相阻尼影响较大 ,对母相阻尼影响较小 ,频率和振幅越高 ,相变阻尼峰越不明显 ;合金在升温过程中出现二次相变 (M→R→P) 。

The low-frequency dynamic damping characteristics for Ti49.2Ni49.3Co1.5 shape memory alloy are investigated by means of DMTA (dynamic mechanical thermal analysis) method with temperature, frequency and strain amplitude varied. The experimental results show that the ternary Ti49.2Ni49.3Co1.5 shape memory alloy exhibits different damping properties as the phase transformation occurring under the combined temperature and stresses. It is also found that the damping capacity of martensite phase and R phase are substantially superior to that of parent phase, and maximum damping capacity, with minimum of elastic modulus concomitant, is encountered during the phase transformation. The effects of frequency and strain amplitude on damping capacity of martensite phase and R phase are larger than that on the parent phase, and the damping peak of phase transformation declines with the increase of frequency and strain amplitude. Two-stage phase transformation M-R-P takes place during heating process, in which the damping peak of M-R transformation is much higher than that of R-P transformation.