Thermal and mechanical properties of Cu-Zr-Al bulk metallic glasses

The effects of adding small amount of aluminum to the binary Cu₅₀Zr₅₀ bulk metallic glass (BMG) on the thermal and mechanical properties were investigated. The Al addition was limited to 3 ≤ x ≤ 10 at.% in order to form fully amorphous bulk samples. Glassy rods of 3 mm diameter of these alloys were prepared by copper mold suction casting. The (Cu₅₀Zr₅₀)_100-xAl_x BMGs (x = 0 and 3 ≤ x ≤ 10 at.%) were characterized with differential scanning calorimetry (DSC), X-ray diffraction (XRD), Vickers microhardness test and nanoindentation, respectively. The glass transition temperatures, crystallization temperatures and super-cooled liquid regions of the specimens increased with increasing Al content. The microhardness of the specimens also increases with increasing Al content. Room temperature nanoindentation was carried out on the cross-section of the rods. The results showed that the nanohardness and creep displacement were dependent on the Al content. © 2006 Elsevier B.V. All rights reserved.