Surface hardening of titanium alloys by oxygen-diffusion-permeation

摘要

The surface oxygen-diffusion-permeation behaviors of Ti based alloys were investigated. MEF4A optical microscopy and HMV-2000 micro-hardness tester were employed to characterize the microstructure and micro-hardness of the oxygen-permeated alloys. The results show that the micro-hardness of Ti based alloys are sharply enhanced by the permeation of oxygen. The microstructure and micro-hardness of oxygen-permeated layer are strongly related to the oxygen-diffusion-permeation techniques. The solid solution of oxygen in α phase can improve the transformation temperature from α phase to β phase and enlarge the region of α phase so as to improve the micro-hardness of surface layer. Therefore, surface oxygen-diffusion-permeation would be a feasible method to reinforce Ti based alloys based on the solid solution of oxygen in α-Ti. At last, a diffusion-solution model was put forward.