Damping property and its mechanism of iron-based shape memory alloy

系统地研究了Fe-Mn-Si形状记忆合金和Fe-Mn高阻尼合金的伪弹性、内耗和低周疲劳性能。FMS表现出两种伪弹性：（1）相变伪弹性，出现在As和M_d温度之间;（2）伪弹性，出现在低于A_s的温度（滞弹性）。后者是由热激活的部分位错运动引起的。内摩擦测量表明，FMS显示应变振幅依赖的阻尼行为。通过低周疲劳试验在大于10 °的应变下测量的阻尼性能<-4>伴随着γ/e界面的可逆运动。所有这些现象都与部分位错的静态或动态运动有关。NbC碳化物颗粒在FMS中的精细分散细化了马氏体板，因为NbC颗粒充当马氏体的形核位点。这种微结构修饰对IM有效， ...更多信息 证明了与γ/e界面的静态运动相关的函数性质，即，合金的形状记忆性能和相变伪弹性。然而，它中断了与界面的动态运动相关的功能特性，例如阻尼特性和内部摩擦。在大于10-3（塑性变形区）的较大应变下，BFM的阻尼性能低于FMS，因为滑移变形超过了BFM中的应力诱导马氏体相变。另一方面，由于高堆垛层错概率，BFM的内摩擦值等于或高于FMS。总结了不同Si、Mn含量、奥氏体基体强度、层错能和ε马氏体体积的FMS的磁转变，并得出了获得良好抗震阻尼性能的必要条件：（1）Ms和TN温度低于室温;（2）层错能低（&lt;20 mJ/m^2）;（3）奥氏体强度高（&gt; 300 MPa）。少

Pseudoelasticity, internal friction and low cycle fatigue property have been systematically investigated on Fe-Mn-Si shape memory alloys (FMS) and on Fe-Mn high damping alloys (BFM). The FMS exhibit two kinds of pseudoelasticity: (1) transformation pseudoelasticity which appears between As and M_d temperatures, (2) pseudoelasticity which appears even below A_s (anelasticity). The latter is caused by motion of thermally activated partial dislocations. Internal friction measurements have revealed that the FMS show strain amplitude dependent damping behavior. Damping properties measured by means of low cycle fatigue tests at strains more than 10^<-4> are accompanied by reversible motion of γ/e interfaces. All of these phenomena are related to static or dynamic motion of partial dislocations. Fine dispersion of NbC carbide particles in FMS refines e martensite plates, because the NbC particles act as nucleation sites for the martensite. This microstructural modification is effective for im … More proving functional properties associated with static motion of γ/e interfaces, i.e., the shape memory properties and transformation pseudoelasticity of the alloys. However, it interrupts the functional properties associated with dynamic motion of the interfaces, such as damping properties and internal friction. The damping properties at larger strains more than 10-3 (plastic deformation region) are lower in the BFM than in the FMS, because slip deformation surpass the stress-induced martensitic transformation in the BFM. On the other hand, the internal friction values of the BFM are equivalent to or higher than those of the FMS, because of high stacking fault probability. Magnetic transition of the FMS with various Si and Mn concentrations, strength of the austenite matrix, stacking fault energy and the volume of e martensite have also been summarized and the necessary condition for obtaining good anti-seismic damping properties are concluded as follows: (1) Ms and TN temperatures be below room temperature, (2) low stacking fault energy (<20mJ/m^2) and (3) high strength of the austenite (>300MPa). Less