Tuning Glass Formation and Mechanical Properties of ZrCoAl(Nb) Bulk Metallic Glass with Nb Microalloying Process

Abstract

In the present study, the effect of Nb addition on mechanical behavior and glass formation in (Zr56Co28Al16)100−xNb(x=0,2,4) bulk metallic glasses was studied. The differential scanning calorimetry (DSC) was used to investigate thermal properties of samples. Further, mechanical behavior of prepared samples was analyzed using quasi-static compressive tests. The results showed that 2 at.% minor addition of Nb enhances the glass forming ability (GFA), but larger amount of Nb (4%) deteriorates GFA. The X-ray diffraction patterns also confirmed that the structures of whole of studied compositions are amorphous. In addition, the compressive test results revealed that 2% addition of Nb significantly improves compressive ultimate strength (up to 2.5 GPa) and increases the plastic strain from 1.1% in the composition having no Nb content to ~ 6%. The observation of shear band branching and also the increase in the density of vein-like patterns in the fracture surface (studied by scanning electron microscopy) also confirm the improvement of plasticity in (Zr56Co28Al16)98Nb2 sample. Our finding highlights the effect of minor alloying on the formation and mechanical properties of bulk metallic glasses.