Consolidation and properties of ball-milled Ti₅₀Cu₁₈Ni₂₂Al₄ Sn₆ glassy alloy by equal channel angular extrusion

Ball-milled Ti₅₀Cu₁₈Ni₂₂Al₄ Sn₆ amorphous powders were consolidated by equal channel angular extrusion (ECAE) near the glass transition temperature. A density of about 97% was achieved. The incomplete densification was a result of the powders experiencing insufficient viscous flow as they partially crystallized into the NiTi intermetallic phase during the ECAE processing. Partial devitrification led to a slight increase in the glass transition temperature (T_g) and minor decrease in the crystallization temperature (T_x), when compared with the starting amorphous powders. However, the width of the supercooled liquid region for the ECAE samples remained large, ∼54 K. Under uniaxial compression, the ECAE consolidated samples failed prematurely before yielding due to brittle failure possibly triggered by the pre-existing minor flaws in the specimens, resulting in a much lower compressive fracture strength with respect to that estimated from the microhardness.