Structure and substructure characterization of solution-treated Ni50.3Ti29.7Hf20 high-temperature shape memory alloy
Structure and substructure characterization of solution-treated Ni50.3Ti29.7Hf20 high-temperature shape memory alloy
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固溶处理Ni50.3Ti29.7Hf20高温形状记忆合金的组织和亚结构表征
DOI：
10.1016/j.scriptamat.2022.114888
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发表时间：
2022
影响因子：
6
通讯作者：
Xie, Kelvin Y.
中科院分区：
文献类型：
--
作者：
Dong, Jiaqi;Umale, Tejas;Young, Benjamin;Karaman, Ibrahim;Xie, Kelvin Y.
采用透射电镜和旋进电子衍射（PED）研究了固溶处理后的马氏体Ni50.3Ti29. 7Hf20高温形状记忆合金（SMA）的结构和亚结构。大多数马氏体板含有高密度的内部（0 0 1）复合孪晶。四种马氏体变体（即，A、B、C和D）。A和B之间的取向关系为（110.64）II型双胞胎，CandD之间的取向关系为（111）I型双胞胎。BandCare由连接平面划分，其中（111）inC平行于（110.64）inB。这些取向关系在其他NiTi或NiTiHf自组装材料中很少观察到，这为理解Ni50.3Ti29.7Hf20自组装材料的相变行为提供了新的视角。在不同的界面附近观察到一些小角度晶界，这可以解释NiTiHf SMA中马氏体再取向和去孪晶的困难。
We investigate the structure and substructure of the solution-treated martensitic Ni50.3Ti29.7Hf20high-temperature shape memory alloy (SMA) by transmission electron microscopy and precession electron diffraction (PED). Most martensite plates contain high-density internal (0 0 1) compound twins. Four martensite variants (i.e.,A, B, C, andD) were observed using PED. The orientation relationships were determined to be (1 1 0.64) Type II twins betweenAandB, and (1 1 1) Type I twins betweenCandD. BandCare divided by junction planes, in which (1 1 1) inCis parallel to (1 1 0.64) inB. These orientation relationships are rarely observed in other NiTi or NiTiHf SMAs, which offers new insight to understand the phase transformation behavior in Ni50.3Ti29.7Hf20SMAs. Several low-angle grain boundaries were observed near the variant interfaces, which may explain the difficulty of martensite reorientation and detwinning in NiTiHf SMAs.