Effects of Cr Microalloying on Structural Evolution, Crystallization Behavior and Micromechanical Properties of ZrCoAlCr Bulk Metallic Glass

This paper deals with the role of minor addition of Cr on the atomic rearrangement and crystallization evolution in a Zr-based bulk metallic glass. For this purpose, Cr elements with 1–4% atomic percentage were added into the alloying composition. The X-ray diffraction results indicated that the trace element led to the increase in disordered structures in the glassy alloy and the decline in population of short and medium scale orders. This event was due to the intensification of structural heterogeneity which was manifested in the change of enthalpy relaxation. The differential scanning calorimetry analysis also showed that all ZrCoAlCr BMG samples included two distinct crystallization peaks during the heating process. However, the increase in Cr content led to the intensification of low temperature peak. This result was consistent with viscosity analysis, in which the viscosity decrement was intensified at the range of low temperature crystallization peak with the rise in Cr content. Moreover, it was found that although the plasticity improved in samples with Cr-content, the strength showed a slight decrease.