This study investigated the crystallization temperature and activation energy of as-spun Ti52.0Ni38.5Cu9.5 ribbon. The as-spun Ti52.0Ni38.5Cu9.5 ribbon is partially crystallized and its wave number Q(p) is lower than those of normal Ti-Ni binary amorphous alloys. The crystallization activation energy E-a of the as-spun Ti52.0Ni38.5Cu9.5 ribbon obtained by Kissinger's method is 422 kJ/mol. Both the thermal stability and the onset crystallization temperature of the as-spun Ti52.0Ni38.5Cu9.5 ribbon are all lower than those of reported Ti-Ni/Ti-Ni-Cu amorphous films/ribbons. The as-spun Ti52.0Ni38.5Cu9.5 ribbon is fully crystallized after annealing at 700 degrees C for 1 h and exhibits a B2 double left right arrow B19 double left right arrow B19' transformation. The ribbon annealed at 700 C for 24 h shows two B2 double left right arrow B19 transformations because it has the mixed microstructure of large and small grains. (C) 2011 Elsevier B.V. All rights reserved.