Physical properties and microstructure performance of laser alloying Zn modified amorphous-nanocrystals reinforced coating

摘要

Zn was firstly used to improve wear resistance of a TA7 (Ti-5Al-2.5Sn) titanium alloy surface by mean of a laser alloying (LA) technique. The synthesis of the hard coating on a TA7 titanium alloy by LA of Co-Ti-Cr-TiB_ 2-Zn-CeO_2 pre-placed powders was investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM). Experimental results indicated lot of the nanocrystals, such as Ti-B/CoZn_(13) and the amorphous phases were produced in such LA coating. The nucleation and growth of the amorphous phases were retarded by the nanocrystals in a certain extent during the crystallization process of the amorphous phases. Compared with a TA7 alloy substrate, an improvement of the wear resistance was obtained for such LA composite coating.