Wear properties of the nonhydrogenated, hydrogenated 0.5 wt%, and dehydrogenated Ti6Al4V alloys were studied through dry sliding wear tests using an M-200 type pin-on-disk wear testing machine in ambient air at room temperature to reveal the effects of hydrogen on wear properties of Ti6Al4V alloy. Morphology and chemical element of worn surface were investigated by means of scanning electron microscope （SEM） and energy dispersive spectroscopy （EDS）. Results show that hydrogen decreases the wear resistance of Ti6Al4V alloy. Wear rate of the Ti6Al4V alloy increases after hydrogenation. Wear rate increases by 244.3 % when 0.5 wt% hydrogen is introduced into a Ti6Al4V alloy. Wear rate of the dehydrogenated Ti6Al4V alloy recovers. Wear mechanisms of the nonhydrogenated, hydrogenated, and dehydrogenated Ti6Al4V alloys are determined. The nonhydrogenated Ti6Al4V alloy is controlled by oxidative wear. The hydrogenated Ti6Al4V alloy is dominated by abrasive wear. Wear mechanism of the dehydrogenated Ti6Al4V alloys is a mixture of oxidative wear and abrasive wear.
Thermohydrogen processing can enhance workability, decrease flow stress and deforming tempera- ture of titanium alloys. In this study, thermohydrogen processing was carried out for metastable β-type TB8 alloy. The microstructures of hydrogenated TB8 alloy were investigated based on scanning electron microscopy （SEM）, transmission electronic microscopy （TEM） as well as X-ray diffraction （XRD） analysis. The results reveal that 6 hydride phase forms in the hydrogenated TB8 alloy, but the amount of β phase increases with hydrogen content increasing. Single β phase appears when the hydrogen content reaches 0.7 wt%. The alloying elements redistrib- ute in the hydrogenated TB8 alloy, and hydrogen leads to the reduction of the alloying elements in β phase. The room-temperature compression tests were performed on a MTS809 machine. It is found that the room-temperature yield strength of hydrogenated TB8 alloy decreases. And minimum yield strength is obtained at a hydrogen content of 0.5 wt%. The ductility does not decrease within 0.7 wt% hydrogen content. These results provide theoretical basis for improving the formability and promoting the applica- tions of TB8 alloy.
