Effect of the Temperature of Mechanical Tests on the Properties of the Nanocrystalline Cu–14Al–3Ni Alloy Subjected to High Pressure Torsion

The tensile tests in combination with the electron microscopy and X-ray technique have provided data on the mechanical properties of the ultrafine-grained (UFG) shape-memory Cu–14 wt % Al–3 wt % Ni alloy at different temperatures and its fracture character. The UFG structure in the alloy has formed during severe plastic deformation performed by high pressure torsion. The study has shown two variants of the mechanical behavior of the UFG alloy depending on the temperature and strain rate during mechanical testing. The first case is the deformation of the alloy in the martensitic state at moderate test temperatures (300, 423, 473 K). This stage is characterized by a high hardening coefficient and moderate uniform relative elongation and reduction. The second case is deformation at higher test temperatures (573, 673 K). It is characterized mainly by large uniform localized plastic deformation and moderate hardening due to dynamic recrystallization.