Displacive transformations in Au-18 wt pct Cu-6 wt pct Al
Displacive transformations in Au-18 wt pct Cu-6 wt pct Al
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Au-18 wt pct Cu-6 wt pct Al 中的位移变换
DOI：
10.1007/s11661-000-0219-7
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
L. Cornish
中科院分区：
文献类型：
--
作者：
F. C. Levey;M. Cortie;L. Cornish
含18wt%Cu和6wt%Al的金合金经历了不完全有序的L21母相和四方产物之间的可逆置换相变。这些转变的特点进行了研究，使用声发射，衍射，X射线衍射和金相。相变产物的形态、母相的结构以及在相变过程中产生的显著声发射表明，如果不是马氏体的话，它们至少是准马氏体的，并且该系统是β相形状记忆合金（SMA）的示例。转变的起始温度取决于样品的先前热历史。马氏体开始（Ms）温度在30 °C和20 °C之间。该系统表现出滞后性，并且当再加热时将恢复到母相，奥氏体起始（As）温度在55 °C和80 °C之间。然而，新铸造或固溶退火和淬火的合金样品不转变为四方相。这种材料需要在30 °C和200 °C之间的温度下老化，然后才能表现出位移转变。“马氏体”相比大多数其他SMA更能抵抗老化诱导的稳定化。
A gold alloy with 18 wt pct Cu and 6 wt pct Al undergoes a reversible displacive phase transformation between an incompletely ordered L21 parent phase and a tetragonal product. The characteristics of these transformations were studied using acoustic emission, dilatometry, X-ray diffraction, and metallography. The morphology of the transformation products, the structure of the parent phase, and the generation of significant acoustic emission during the transformations indicate that they are at least quasi-martensitic, if not martensitic, and that this system is an example of a β-phase shape-memory alloy (SMA). The onset temperatures of the transformations depend on the prior thermal history of the sample. The martensite start (Ms) temperature is between 30 °C and 20 °C. The system exhibits hysteresis and will revert to the parent phase when reheated, with an austenite start (As) temperature between 55 °C and 80 °C. However, freshly cast or solution-annealed and quenched samples of the alloy do not transform to the tetragonal phase. Aging of such material at temperatures between 30 °C and 200 °C is required before they will manifest the displacive transformation. The “martensite” phase is considerably more resistant to aging-induced stabilization than that of most other SMAs.