Unraveling Frequency Effects in Shape Memory Alloys: NiTi and FeMnAlNi
Unraveling Frequency Effects in Shape Memory Alloys: NiTi and FeMnAlNi
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DOI：
10.1007/s40830-021-00335-0
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发表时间：
2021-06
影响因子：
2.2
通讯作者：
R. Sidharth;A. Mohammed;W. Abuzaid;H. Sehitoglu
中科院分区：
文献类型：
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作者：
R. Sidharth;A. Mohammed;W. Abuzaid;H. Sehitoglu
由于存在内部界面，例如马氏体-马氏体界面和马氏体中的内部孪晶界，形状记忆合金（SMA）可用于被动/主动阻尼应用中。由于相变潜热，加载/卸载循环期间的温度上升/下降预计将与SMA的机械响应动态耦合，并影响正向/反向相变的应力水平，从而影响滞后区域（即耗散能量）。此外，由于瞬时热传递效应，每个循环的温度变化是加载频率的函数。为此，我们首次展示了一种速率不敏感的形状记忆合金系统Fe43.5Mn34Al15Ni7.5，该合金也表现出接近零的温度依赖性应力-应变响应。相反，我们发现，Ni50.8Ti，这是广泛使用的商业，是高度的速率敏感。通过简单的原位实验，辅以热机械建模，我们确定了决定频率灵敏度的关键材料参数。相应的结果进行了讨论，根据不同的机制有助于SMA的阻尼能力。
With the presence of internal interfaces such as the austenite–martensite interface and the internal twin boundaries in the martensite, shape memory alloys (SMAs) can be employed in passive/active damping applications. Due to the latent heat of transformation, a temperature rise/drop during a load/unload cycle is expected to dynamically couple with the mechanical response of the SMA and influence the stress levels of forward/reverse transformation and thus the hysteretic area (i.e. the dissipated energy). Additionally, the temperature change per cycle is a function of loading frequency due to momentary heat transfer effects. To this end, for the first time, we demonstrate a rate insensitive shape memory alloy system, Fe43.5Mn34Al15Ni7.5which also exhibits near-zero temperature dependent stress–strain response. Contrastingly, we show that Ni50.8Ti, which is widely used commercially, is highly rate sensitive. With straightforward in situ experiments, complemented with thermomechanical modelling, we pinpoint the key material parameter which dictates frequency sensitivity. The corresponding results are then discussed in the light of different mechanisms contributing to the damping capacity of SMAs.