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

Abstract
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 completely amorphous but contains fine-grained crystals. Compression tests have been performed over a wide temperature range for this alloy (A-alloy) and also for a commercial bulk metallic glass, the so-called Johnson alloy, with the composition Zr₄₁Ti_l4Ni₁₀Cu_12.5Be_22.5 (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 alloys. As the temperature is increased further specimens begin to undergo homogeneous yielding ; in B-alloy the yield stress decreases rapidly with increasing temperature to almost zero at 620K followed by brittle fracture at higher temperature due to crystallization, whereas in A-alloy the yield stress decreases gradually towards zero at 1200K without exhibiting brittie fracture. The different deformation behaviors between the two alloys at high temperatures are discussed.