(中南大学 材料科学与工程学院， 长沙 410083)
摘 要: 利用X射线衍射、 扫描电镜和倒置低频扭摆仪研究了不同热处理状态Ti-50.8％Ni(摩尔分数)合金的低频阻尼性能。结果表明： 固溶处理试样只存在马氏体相变内耗峰， 而时效处理试样中既有马氏体相变内耗峰， 也发现有R相变内耗峰，相变内耗峰均对应弹性模量极小值， 相变内耗峰与频率成反比； 在时效处理试样中， 马氏体相和R相的阻尼性能高于母相（B2)； 时效处理对马氏体相变有抑制作用； 在400 ℃时效的TiNi合金中， 于200 K左右处发现内耗峰， 随着频率的增加， 低温内耗峰向高温方向运动，此内耗峰与时效析出的Ti3Ni4粒子钉扎位错有关， 用钉扎位错脱钉的G-L模型解释了低温内耗峰， 此内耗峰的脱钉既包括机械脱钉， 也包括热激活脱钉。
关键字: TiNi； 形状记忆合金； 阻尼性能； 马氏体相变； 内耗
of Ti49.2Ni50.8 alloy
（Department of Materials Science and Engineering，
Central South University， Changsha 410083， China）
Abstract: The low-frequency damping capacities of Ti-50.8%Ni(molar fraction) alloy were investigated under different heat-treating conditions by XRD, SEM and low frequency inverted torsion pendulum. The results show that there is only damping peak of martensite transformation in solution treated specimen, and there are damping peak of martensite transformation and R phase transformation in 400 ℃ aged specimen. The damping peak of phase transformation corresponds to the minimum of elastic modulus and varies inversely with frequency. In the aged specimen, the internal friction of martensite phase or R phase are higher than that of parent phase(B2). The aged treatment impedes martensite phase transformation. The damping peak at 200 K of the 400 ℃ aged TiNi alloy moves to high temperature with increment of frequency. The damping peak relating with the Ti3Ni4 particle can be interpreted by unpinning process of pinned dislocation with G-L model. The unpinning process includes mechanical unpinning process and thermally activation unpinning process.
Key words: TiNi; shape memory alloy; damping capacity; martensitic transformation; internal friction
