To offer a response to the increasing interest on high-temperature shape memory alloys, mainly driven by the aeronautic and aerospace industries, the design and characterization of Cu-Al-Ni shape memory alloys with high transformation temperatures, between 373 K and 473 K, are approached. The present alloy design is based on the transformation from cubic β₃ austenite to the monoclinic β'₃ martensite, which offers the advantage of exhibiting not only higher transformation temperatures but also a thermal hysteresis of about 12 K, much smaller than the orthorhombic γ'₃ martensite historically considered for this alloy system. The influence of the alloy concentration and the thermal treatments, on the martensitic transformation temperatures is systematically analyzed and a quantitative and predictive equation is proposed. The influence of the stress on the transformation was also studied under two experimental conditions: at constant stress as a function of temperature (shape memory effect) and at constant temperature as a function of the stress (superelastic effect). A double stress-induced transformation from β₃ to β'₃ and α'₃ with an outstanding reversible and reproducible 24% superelastic strain is also reported. The experimental results allows also determine the Clausius-Clapeyron diagrams for this series of alloys, as a fundamental tool for further design of sensing and actuating devices based on these high-temperature shape memory alloys.

为了回应对主要由航空和航天工业推动的高温形状记忆合金的日益增长的兴趣，设计并表征了具有373 K至473 K的高转变温度的Cu-Al-Ni形状记忆合金，被接近。本发明的合金设计是基于从立方β转变₃奥氏体单斜β“ ₃马氏体，它提供了显示出不仅具有更高的转变温度，但也的热滞后的优点约12 K，比斜方晶γ小得多” ₃过去曾对该合金系统考虑过马氏体。系统分析了合金浓度和热处理工艺对马氏体相变温度的影响，提出了定量和预测方程。还在两个实验条件下研究了应力对相变的影响：在恒定应力下随温度变化（形状记忆效应）和在恒定温度下随应力变化（超弹性效应）。从β双应力诱导相变₃至β“ ₃和α” ₃还报道了具有出色的可逆和可再现的24％超弹性应变。实验结果还可以确定该系列合金的Clausius-Clapeyron图，作为进一步设计基于这些高温形状记忆合金的传感和致动装置的基本工具。