Transformation characteristics of shape memory alloy composites
Transformation characteristics of shape memory alloy composites
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DOI：
10.1088/0964-1726/20/9/094002
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发表时间：
2011-09
影响因子：
4.1
通讯作者：
B. Lester;Y. Chemisky;D. Lagoudas
中科院分区：
文献类型：
--
作者：
B. Lester;Y. Chemisky;D. Lagoudas
形状记忆合金（SMA）复合材料的应用范围不断扩大。对于新的应用，SMA复合材料正在开发纳入各种各样的矩阵。本文探讨了这些新成分对SMA非均质相变行为和有效复合行为的影响。提出了一种结合微观力学方法和SMA本构模型的分析方法来确定复合材料的整体相变特性。确定了相变前后的有效相图、有效相变应变和复合应力状态。对SMA -陶瓷复合材料的分析结果表明，相变后，两相之间的应力分布发生了变化，SMA相的受力方向减小，而陶瓷相的受力方向增大。这种应力重分布降低了加载方向上的局部转变应变，导致在特定温度下启动和完成正向和反向转变所需的外加应力增加。通过参数化研究，探讨了基体弹性模量和SMA不均匀性体积分数对相变行为的影响，以了解它们对SMA复合材料设计的影响。
Shape memory alloy (SMA) composites are being used in an ever-expanding set of applications. For new applications, SMA composites are being developed incorporating a wide variety of matrices. The effect of these new compositions on the transformation behavior of the SMA inhomogeneities and on the effective composite behavior is explored here. An analytic methodology combining micromechanical methods with an SMA constitutive model is developed to determine the overall transformation properties of the composite. Specifically, the effective phase diagram, the effective transformation strains and the composite stress state before and after transformation are determined. The results obtained from the analyses of an SMA–ceramic composite show that after transformation the stress distribution between the two phases is modified such that the stress in the direction of applied loading in the SMA phase is reduced while the stress in the same direction in the ceramic phase increases. This stress redistribution decreases the local transformation strain in the direction of loading and results in an increase of the applied stress necessary to initiate and complete the forward and reverse transformation at a specific temperature. The effects of the elastic modulus of the matrix and volume fraction of the SMA inhomogeneities on the transformation behavior are explored through a parametric study to understand their influence on SMA composite design.