Effect of Ti addition on crystallization behavior of a Zr-based bulk metallic glass

•Crystallization activation energy of the Ti-free BMG is larger than that of the BMGs (x = 0.2 and 0.4 at.%) but smaller than that of the BMGs (x = 0.1, 0.3 and 0.5 at.%).•Crystallization phases are ZrNi and Zr2Ni7 for the partially and fully crystallized BMGs.•Local crystallization activation energy decreases with increasing crystallization fraction.•Crystallization mechanism is nearly affected by the Ti addition and the heating rate.•Crystallization mechanism is nearly affected by the Ti addition and the annealling temperature.