论文标题
在张力，压缩和弯曲驱动循环下高温形状记忆合金合金的相变特征
Phase Transformation Characteristics of High-Temperature Shape Memory Alloy under Tension, Compression, and Bending Actuation Cycling
论文作者
论文摘要
形状内存合金（SMA）是一类独特的金属合金，可以通过固体到固相变的变形周期性地维持较大的变形并恢复设计的几何形状。 SMA提供了有利的致动能量密度特性，使其适用于需要重大，重复的工作输出的工程应用。为了促进，考虑到高温SMA（HTSMA）的各向异性材料响应（HTSMA）的开发和验证，由HTSMA标本上的单轴和纯弯曲驱动循环测试是由定制构建的测试框架执行的。研究了Ni $ _ {50.3} $ tihf $ _ {20} $ HTSMA在单轴张力/压缩和四点弯曲致动周期下的相变特性。实验结果表明，在单轴驱动循环载荷条件下，多晶HTSMAS具有强烈的张力压缩不对称性。此外，四点梁弯曲测试表明，当HTSMA受到循环致动弯曲条件的约束时，存在固有的现象，即，由于不对称张力压缩相变和束的不同侧面的不对称产生，零晶体中性轴移动。进行的实验提供了宝贵的信息，以在统一的建模工作中考虑张力压缩不对称性和跳闸应变的产生，以开发和改善SMA构型模型。作为未来的工作，对其他HTSMA组件的其他实验，例如带有凹口或切口的扭矩管和标本，在驱动循环下将为基于HTSMA的执行器提供更全面的验证数据和组件性能。
Shape Memory Alloys (SMAs) are a unique class of intermetallic alloys that can cyclically sustain large deformations and recover a designed geometry through a solid-to-solid phase transformation. SMAs provide favorable actuation energy density properties, making them suitable for engineering applications requiring a significant, repeated, work output. To facilitate the development and validation of an SMA constitutive model considering the evolving anisotropic material response for High-Temperature SMA (HTSMA), uniaxial and pure bending actuation cycling tests on HTSMA specimens are performed by a custom-built testing frames. The phase transformation characteristics for Ni$_{50.3}$TiHf$_{20}$ HTSMA under uniaxial tension/compression and four-point bending actuation cycles are investigated. The experimental results show that the polycrystalline HTSMAs has a strong tension-compression asymmetry under uniaxial actuation cycling loading conditions. Furthermore, the four-point beam bending test shows that there is an intrinsic phenomenon when HTSMAs are subjected to cyclic actuation bending conditions, i.e., the zero-strain neutral axis shifts as a result of the asymmetric tension-compression phase transformations and the asymmetric generation of TRIP strains on different sides of the beam. The conducted experiments provide invaluable information to develop and improve the SMA constitutive model considering tension-compression asymmetry and TRIP strain generation within a unified modeling effort. As future work, additional experiments on other HTSMA components, such as torque tubes and specimens with notches or cutouts, under actuation cycling would provide more comprehensive validation data and component performance for HTSMA-based actuators.
