Evaluation of Micro-Sized BMG Tensile Specimen Fabricated by Electrolytic Polishing Technique

Abstract

An electrolytic polishing technique was used to fabricate micro-sized tensile specimens from two Zr₅₅Al₁₀Ni₅Cu₃₀ bulk metallic glass samples. One sample had a fully amorphous phase, while the other had dendrites with an average size of 33 μm within the amorphous matrix. A scanning electron microscope showed that specimens fabricated by electrolytic polishing had smooth surfaces. The specimens were then subjected to tensile tests at room temperature. The fully amorphous specimen had a fracture strength of 1,640 MPa. This specimen also showed slight plastic deformation after yielding, as well as vein patterns and smooth surface on the fracture surface. Multiple thin shear bands generated from a shear band were observed on the side surface of fractured specimen. The specimen containing dendrites was quite low in strength compared to the fully amorphous specimen, and had yield and fracture strengths of 460 and 600 MPa, respectively. The specimen containing dendrites also showed plastic deformation and work hardening after yielding, as well as vein patterns and a brittle fracture region on the fracture surface.