Metallic-glass–crystal composites of Cu_47.5Zr_47.5Al₅ and Cu₁₀Zr₇-reinforced Cu_46.5Zr₄₈Al₄Nb_1.5 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 Cu_46.5Zr₄₈Al₄Nb_1.5 nanocrystalline materials. Electrochemical measurements show that Cu_46.5Zr₄₈Al₄Nb_1.5 nanocrystalline material has good corrosion resistance in NaCl and H₂SO₄ solutions, even better than the parent metallic glasses in some aspects.