Microstructure, phase transformation and mechanical properties of Ni–Mn–Ga–Y magnetic shape memory alloys
Microstructure, phase transformation and mechanical properties of Ni–Mn–Ga–Y magnetic shape memory alloys
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DOI：
10.1016/j.jallcom.2011.06.013
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发表时间：
2011-09
影响因子：
6.2
通讯作者：
J. Sui;Xin Zhang;L. Gao;W. Cai
中科院分区：
文献类型：
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作者：
J. Sui;Xin Zhang;L. Gao;W. Cai
研究了稀土Y对ni50mn29ga21多晶铁磁形状记忆合金（FSMA）显微组织、相变及力学性能的影响。结果表明，Ni-Mn-Ga-Y合金的显微组织由基体和富y相组成。富Y相首先在基体中少量均匀弥散，随着Y取代Ga的增加，富Y相在晶界处趋于偏析。富Y相指向Y(Ni,Mn)4Ga相，具有六方ccu5型结构。随着Y含量的增加，出现从5M到7M，再到非调制T马氏体的结构转变。随着Y含量的增加，马氏体相变温度显著升高，而居里温度基本保持不变。结果表明，适当添加Y可显著提高合金的屈服强度和塑性。讨论了Y含量对合金力学性能改善和马氏体转变温度的影响机理。
Influence of rare earth Y addition on the microstructure and phase transitions and mechanical properties of polycrystalline Ni50Mn29Ga21ferromagnetic-shape memory alloy (FSMA) are investigated. It is shown that microstructure of the Ni–Mn–Ga–Y alloys consists of the matrix and the Y-rich phase. The Y-rich phase firstly disperses homogeneously in the matrix with small amounts and then tends to segregate at the grain boundaries with increasing Y substitution for Ga. The Y-rich phase is indexed to Y(Ni,Mn)4Ga phase with a hexagonal CaCu5type structure. The structural transition from 5M to 7M, and then to non-modulated T martensite appears with the increase of Y content. The martensitic transformation temperature increases remarkably with increasing Y content, whereas the Curie temperature almost keeps unchanged. It is revealed that the appropriate addition of Y significantly enhances the yield strength and improves the ductility of the alloys. The mechanism on the influence of Y content on the improved mechanical properties and martensitic transformation temperature is also discussed.