Effect of annealing treamenton formation of intermetallic phase in cold-sprayed Ni/Ti mechanical alloying coating

Three kinds of Ni/Ti mechanical alloying powder prepared by mechanical alloying at differentmilling time are employed o from Ni/Ti coatings by cold spraying.The micro-structures of the coatings annealing under different conditions are characterized by scanning electron microscopy(SEM) and X-ray diffraction(XRD).It is found that the formation temperature of Ni-Ti inter metallics from the cold-sprayed alloy is decreased with increasing ball milling time for powder preparation.Moreover,the phase constitutions change from Ni₃Ti,B2-NiTi and Ti₂Ni to Ni₃Ti and Ti₂Ni.The increase of annealing temperature only leads to the change of the relative content of different intermetallic phases in the coating.The results show that in termetallic B2-NiTi phase formed during annealing exhibits good stability during cooling process.