(华南理工大学 材料科学与工程学院，广州 510640)
摘 要: 研究了不同孔隙特征多孔NiTi合金的内耗与相变行为及其频率响应，提出用等效内耗参数表征多孔NiTi合金实体部分的阻尼能力。结果表明：多孔NiTi合金内耗峰产生的主要诱发因素是相变及应力诱发下各种界面(含孪晶界、相界面等)的迁移；在不同的加载频率下，多孔NiTi合金的内耗值曲线按双曲线规律变化；在相同的频率和振幅下，孔隙率、孔隙尺寸和开孔度的增加导致与界面迁移相关内耗幅值有所削弱；各内耗峰值温度也受到孔隙参数的影响；多孔NiTi合金的等效内耗峰值明显高于致密NiTi合金。
关键字: 多孔NiTi合金；内耗；相变；孔隙率；频率效应
porous NiTi alloys with variable porosities
（School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:The damping behaviours of porous NiTi alloys with different pore characteristics were studied, and a new parameter for porous NiTi alloys, i.e., equivalent internal friction, was proposed to characterize their effectiveness in energy absorption. The results show that the internal friction peaks of porous NiTi alloys are induced by phase transformation and the stress induces hysteretic motions of interfaces such as twin boundaries and phase boundaries. At different frequencies, the intensity of internal friction peaks changes following the hyperbolic relation. Under the same testing conditions (i.e., at certain frequency and amplitude), the increases of porosity, pore-size and open porosity of the alloys lead to the decrease of amplitude of the internal friction associated with interface movement. The increase in porosity can also result in change of internal friction peak temperatures. The porous NiTi alloys have obviously high equivalent internal friction value than the dense NiTi alloys.
Key words: porous NiTi alloy; internal friction; phase transformation; porosity; frequency effect
