Determination of martensite structures of the Au7Cu5Al4 and Au7Cu5.7Al3.3 shape-memory alloys
Determination of martensite structures of the Au7Cu5Al4 and Au7Cu5.7Al3.3 shape-memory alloys
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Au7Cu5Al4 和 Au7Cu5.7Al3.3 形状记忆合金马氏体结构的测定
DOI：
10.1016/j.actamat.2014.07.039
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发表时间：
2014
期刊：
影响因子：
9.4
通讯作者：
M. Cortie
中科院分区：
文献类型：
--
作者：
M. Elcombe;C. Kealley;V. Bhatia;G. Thorogood;D. J. Carter;M. Avdeev;M. Cortie
Au7Cu5Al4 的 β 相经历可逆的形状记忆相变，对此有几个相互冲突的马氏体相的报道。在这里，我们展示了用于获得马氏体的冷却温度的重要性。如果 Au7Cu5Al4 从母相条件冷却到低温，例如低于 200 K，马氏体相为斜方相（空间群 Pcmn,a= 4.4841 Å,b= 5.8996 Å,c= 17.8130 Å）；然而，当这种组合物冷却至仅 ∼260 K 时，它通常由斜方相和单斜相的混合物组成（后者具有空间群 P21/m，a= 4.4742 Å，b= 5.9265 Å，c= 13.3370 Å，β= 91.425°）。相反，如果冷却至 ∼260 K，Al 含量降低的样品 (Au7Cu5.7Al3.3) 会完全转变为单斜相。
Theβ-phase of Au7Cu5Al4undergoes a reversible shape-memory phase transformation for which several conflicting martensite phases have been reported. Here we show the significance of the cooling temperature used to obtain the martensite. If Au7Cu5Al4is cooled from the parent phase condition to cryogenic temperatures, e.g. below 200 K, the martensitic phase is orthorhombic (space groupPcmn,a= 4.4841 Å,b= 5.8996 Å,c= 17.8130 Å); however, when this composition is cooled to only ∼260 K it will in general consist of a mixture of orthorhombic and monoclinic phase (the latter has space groupP21/m,a= 4.4742 Å,b= 5.9265 Å,c= 13.3370 Å,β= 91.425°). In contrast, a sample with decreased Al content (Au7Cu5.7Al3.3) transforms fully to monoclinic phase if cooled to ∼260 K.