Effects of alloying elements on crystallization kinetics of Ti-Zr-Be bulk metallic glass

It has been found that the partial substitution of Fe, Al, Ag, Cu, Ni, V, or Cr for Be effectively enhances the glass-forming ability of Ti-Zr-Be ternary alloy. The influence of different alloying elements on crystallization kinetics of Ti41Zr25Be34 alloy has been investigated by isothermal and isochronal differential calorimetry combined with X-ray diffraction. Among the selected alloying elements, Fe, Al, Cu, Ni, or Cr can enhance the thermal stability, while the Ag- and V-containing alloys exhibit a slightly narrower supercool liquid region. The crystallization of all the eight alloys proceeds through at least two exothermic events. The apparent activation energies of glass transition and crystallization have been determined based on the Kissinger equation. The substitution of Al, Ag, Cu, or Ni for Be does not change the product of the primary crystallization of the base alloy. However, with the addition of beta stabilized elements (Fe, V, and Cr), the formation of beta-Ti as primary phase is promoted. The overall nucleation and growth characteristics of the parent, Al-, Ag-, Cu-, Ni-, V-, and Cr-additive alloys, are similar. Compared with the other seven alloys, Ti41Zr25Be28Fe6 alloy exhibits much larger Avrami exponents with an average value of 5.26, indicating a high-dimensional growth with increasing nucleation rate.