Tailoring microstructure and properties of CuZrAl(Nb) metallic-glass–crystal composites and nanocrystalline alloys obtained by flash-annealing

Metallic-glass–crystal composites of Cu47.5Zr47.5Al5 and Cu10Zr7-reinforced Cu46.5Zr48Al4Nb1.5 nanocrystalline materials are obtained by flash-annealing of metallic-glass ribbons. In situ high-energy X-ray diffraction reveals the deformation mechanism of the alloys upon tensile loading. For the composites and nanocrystalline materials, a small remaining amount of the metallic glass and/or the presence of the Cu10Zr7 phase significantly increase the value of yield stress while maintaining good tensile ductility. In general, the obtained materials exhibit a reversible martensitic transformation (MT) between the B2 CuZr and B19’/B33 phases during tensile loading and unloading. However, the reversibility of MT depends on the alloy composition, crystalline phases, and the number of (un)loading cycles. Serrated-like fluctuations on tensile stress-strain curves and a sign of twinning in the Cu10Zr7 crystals are found after yielding in the Cu10Zr7-reinforced Cu46.5Zr48Al4Nb1.5 nanocrystalline materials. Electrochemical measurements show that Cu46.5Zr48Al4Nb1.5 nanocrystalline material has good corrosion resistance in NaCl and H2SO4 solutions, even better than the parent metallic glasses in some aspects.