Processing, characterization and properties of specially constituted Zr-based bulk amorphous alloys

Bulk metallic glasses (BMGs) are an emerging class of materials. The amorphous alloys have very attractive properties. There is potential for applications. The quaternary and pentanery (ZrCuAlNi)/sub 100-x/Ti/sub x/ (x = 0, 2 and 5 at. %) alloys were synthesized by melting 2-3N pure metals in an arc furnace. Amorphous ingots were produced using Cu mold casting technique. The alloys showed wide supercooled liquid region del T/sub x/, high thermal stability and good glass-forming ability (GFA). Many thermal parameters like T/sub rg/, gamma, alpha, beta and omega were measured employing high temperature differential scanning calorimetry (DSC). Structural characterization was carried out by X-ray diffraction (XRD) technique. Microstructural characterization was conducted using high resolution field emission scanning electron microscopy (FESEM) and elemental analysis was done using energy dispersive spectroscopy (EDS). Crystallization behavior and phase formation was studied. Activation energy for crystallization was calculated using Kissinger and Ozawa equations. The alloys show double stage crystallization. Mechanical properties were measured. Compression test was carried out and fracture strength and strain were determined. The fracture behavior was studied which showed veins like patterns, shear bands formation and liquid droplets. (author)