Effect of compressive load on the martensitic transformation from austenite to 5M martensite in a polycrystalline Ni-Mn-Ga alloy studied by in-situ neutron diffraction
Effect of compressive load on the martensitic transformation from austenite to 5M martensite in a polycrystalline Ni-Mn-Ga alloy studied by in-situ neutron diffraction
复制标题
通过原位中子衍射研究压缩载荷对多晶 Ni-Mn-Ga 合金中从奥氏体到 5M 马氏体马氏体转变的影响
DOI：
10.1016/j.jallcom.2016.01.090
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发表时间：
2016
影响因子：
6.2
通讯作者：
Zuo Liang
中科院分区：
文献类型：
--
作者：
Li Zongbin;Zou Naifu;Yang Bo;Gan Weimin;Hou Long;Li Xi;Zhang Yudong;Esling Claude;Hofmann Michael;Zhao Xiang;Zuo Liang
研究了单向压缩载荷对定向凝固Ni-Mn-Ga多晶合金中奥氏体向5 M马氏体转变的影响< 0 0 1>，该合金具有< 1 1 0>平行于凝固方向（SD）的A和A择优取向。基于中子衍射，直接证据上的变体再分布引起的热机械处理和选择的优先变量被发现是强烈依赖于奥氏体取向。对于具有< 0 0 1>A择优取向的奥氏体，压缩加载方向（LD）沿着SD可以促进{0 2 0} 5 M ε SD（LD）的择优变体的形成。另一方面，对于具有< 1 1 0>A择优取向的奥氏体，具有{1 2 5} 5 M/{1 $> 2 5} 5 M的奥氏体晶粒尺寸（LD）的变体在热机械处理后更有利。这种变体的选择源于马氏体相变中各向异性晶格畸变与外部约束之间的协调。本研究可为多晶Ni-Mn-Ga合金在外场作用下的变形选择提供基础信息，并为外场训练优化合金组织提供必要的指导。
In this study, the influences of uniaxial compressive load on martensitic transformation from austenite to 5M martensite were studied in a directionally solidified Ni–Mn-Ga polycrystalline alloy with coexisting< 0 0 1> A and< 1 1 0> A preferred orientations parallel to the solidification direction (SD). Based on the neutron diffraction, the direct evidence on the variant redistribution induced by the thermal-mechanical treatment was presented and the selection of preferential variants was found to be strongly dependent on the austenite orientation. For the austenite with a< 0 0 1> A preferred orientation, the compressive loading direction (LD) along the SD can promote the formation of preferred variants with {0 2 0} 5M⊥ SD (LD). On the other hand, for the austenite with a< 1 1 0> A preferred orientation, the variants with {1 2 5} 5M/{1¯ 2 5} 5M⊥ SD (LD) are more favorable after the thermal-mechanical treatment. Such variant selection is originated from the accommodation between the anisotropic lattice distortion in martensitic transformation and the external constraint. The present investigations may offer some fundamental information on variant selection subject to external stress field and the necessary guidelines for microstructure optimization of polycrystalline Ni–Mn-Ga alloys through external field training.