Properties of Ti-Al Alloying Layer on Titanium Alloy Surface by Double Glow Discharge Plasma Aluminizing

摘要

The Ti-Al alloying diffusion layer was fabricated on the surface of titanium alloy (Ti6Al4V) by double glow discharge plasma technique and hollow cathode effect. The pure aluminum was selected as the source cathode and Ar as the working gas. The microhardness of the surface of sample was tested by HMV-1T micro-sclerometer. The cross sectional microstructure and the phase structure of the Ti-AI alloying layer were analyzed by means of the scanning electron microscopy (SEM) and X-ray diffraction (XRD). The friction and wear behavior of the Ti-AI alloying layer under dry sliding against SAE52100 steel was evaluated on a WTM-1 ball-on-disc test rig. The corrosion resistance of the Ti-AI alloying layer was tested using CS300P electrochemical corrosion workshop in the 0.5mol/L sulphuric acid solution. The results showed that it was feasible to prepare a Ti-AI alloying layer of 20μm thick by this process at 950℃ for 5h. The phases are mainly Ti3Al and TiAl in the Ti-AI alloying layer. It has been found that the Ti-AI alloying layer has excellent friction and wear-resistant behaviors. The Ti6A14V alloy was characterized by adhesion wear and scuffing under dry sliding against the steel, while the Ti-AI alloying layer experienced much abated adhesion wear and scuffing under the same testing condition. The Ti-AI alloying layer has excellent corrosion resistance properties too. The corrosion velocity was obviously slowed down remarkably.