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In this work an alternative technique to produce shape memory wires directly from the molten was developed. In this method, the alloy is melted in a high frequency induction furnace with the levitation melting technique and suctioned through a quartz tube connected to a low-pressure chamber. Cu-AI-Nb wires with a diameter of 1.3 mm and length of about 150mm were obtained by this procedure. Their microstructure and physical properties were studied using X-ray diffraction, optical microscopy and DSC thermal analysis.

This work focuses on the necessary conditions for obtaining Cu-Al-Nb based shape memory alloys by means of mechanical alloying powder metallurgy. The Cu, AI, and Nb elemental powders were pre-alloyed using a pulverisette high energy ball milling for Cu-13. 0wt%AI-2.0wt%Nb alloy. The microstructural evolution during the milling was investigated by using X-ray diffraction. It was observed that the Cu(AI) solid solution can be obtained with short milling times. A relative sintered density on the order of 93% on the theoretical value was achieved. Additionally, after quenching the microstructure of the sintered compacts was formed by the 18R type martensite and Cu(AI) solid solution.

Nb modified Cu-Al-Ni shape memory alloys with different Ni contents (1.0, 2.0 and 3.0wt%) were processed using the melt spinning technique. The microstructures and the characteristic transformation temperatures were detennilled by x-ray diffraction and thennal analysis (differential scanning calorimeter and thennomechanical analysis) respectively. It was observed that all as-melt spun ribbon microstructures present the $\gamma_2$phase and some peaks that are thought to be from the 18R type martensite. After water quenching the microstuctures of the ribbons are fully 18R and 2H type martensites. The typical Ms, Mf, As and Af temperatures are shifted to lower values with increasing the Ni concentration.

In this study, alloys with a Cu-13.84Al-1.0Nb (wt. %) composition and different content of nickel (1.0, 2.0 and 3.0 wt%) were cast in a high frequency induction furnace, and reprocessed by the suction method for obtaining wires. The effect of Ni additions and the different cooling rates on the martensite stability and shape recovery were studied. It was observed that for alloys with a low nickel content the addition of Nb strongly influences the effect of tNi element by hindering the formation of the $\gamma_2$(Al4Cu9) phase. ln alloys with a higher Ni content the XRD analysis clearly shows that the microstructure consists of 18R and 2H martensite.