Deformation behavior of Zr-based bulk metallic glasses in a wide temperature range

We have developed a new multi-component glassy alloy of Zr54Mn5Co10Ni10Cu21 . The water-quenched sample with a diameter of 2.5mm of the alloy is not co mpletely amorphous but contains fine-grained crystals. Compression tests ha ve been performed over a wide temperature range for this alloy (A-alloy) an d also for a commercial bulk metallic glass, the so-called Johnson alloy, w ith the composition Zr41Ti14Ni10Cu12.5Be22.5 (B-alloy) for comparison. The specimens undergo shear fracture below 723K in A-alloy and below 573K in B- alloy. The shear fracture stresses are in the range 1.75+/-0.4GPa in both a lloys. As the temperature is increased further specimens begin to undergo h omogeneous yielding; in B-alloy the yield stress decreases rapidly with inc reasing temperature to almost zero at 620K followed by brittle fracture at higher temperature due to crystallization, whereas in A-alloy the yield str ess decreases gradually towards zero at 1200K without exhibiting brittle fr acture. The different deformation behaviors between the two alloys at high temperatures are discussed.