Martensitic transformation and mechanical properties of polycrystalline Ni50Mn29Ga21−xGdx ferromagnetic shape memory alloys
Martensitic transformation and mechanical properties of polycrystalline Ni50Mn29Ga21−xGdx ferromagnetic shape memory alloys
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DOI：
10.1016/j.jallcom.2006.01.037
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发表时间：
2006-11
影响因子：
6.2
通讯作者：
L. Gao;W. Cai;A. Liu;L. C. Zhao
中科院分区：
文献类型：
--
作者：
L. Gao;W. Cai;A. Liu;L. C. Zhao
研究了重稀土Gd对多晶Ni50Mn29Ga21形状记忆合金组织、马氏体相变和力学性能的影响。结果表明，Ni-Mn-Ga-Gd合金的显微组织由基质相和富Gd相组成。随着Gd取代量的增加，富Gd相首先在基体中均匀弥散，然后趋于偏聚在晶界。随着Gd含量的增加，马氏体相变温度显著提高，晶粒度明显减小。不同的Gd含量会出现不同的马氏体相变。当Gd含量大于0.1at%时，马氏体相结构由5m和0.1at%Gd转变为7m。结果表明，Gd的加入显著提高了合金的抗弯强度，改善了合金的塑性。并对其力学性能改善的机理进行了探讨。
The aim is to investigate the influence of heavy rare earth Gd addition on the microstructure, martensitic transformation and mechanical properties of polycrystalline Ni50Mn29Ga21shape memory alloy. It is shown that microstructure of the Ni–Mn–Ga–Gd alloys consists of the matrix and the Gd-rich phase. The Gd-rich phase firstly disperses homogeneously in the matrix with small amounts and then tends to segregate at the grain boundaries with the increase of Gd substitution for Ga. With increasing Gd content, the martensitic transformation temperatures increase remarkably and the grain size is reduced obviously. Different martensitic phase transformation appears in different Gd content. Martensite structure changes from 5M with 0.1at% Gd to 7M when the content of Gd is more than 0.1at%. It is revealed that the addition of Gd significantly enhances the bending strength and improves the ductility of the alloys. The mechanism of the improved mechanical properties is also discussed.