Unusual solidification behavior of a Zr–Cu–Ni–Al bulk glassy alloy made from low-purity Zr

This paper reports on the unusual solidification behavior of Zr55Cu30Al10Ni5 bulk glassy alloy produced using low-purity Zr in which both primary and eutectic-type structural constituents were formed simultaneously during solidification of the melt. Additionally, two different types of primary crystalline phases were observed. One of them was cF96 and contained all the four constituent elements. Reasons for these observations have been related to the presence of impurities in the alloy leading to inhomogeneous nucleation and consequent modification of the crystallization behavior. The structure and thermal stability of the samples were studied using X-ray diffraction, scanning and transmission electron microscopy, as well as differential scanning calorimetry methods. Although the cast alloys made with low-purity Zr showed somewhat decreased glass-forming ability, their mechanical strength was still high.