Improvement of Surface Properties of Titanium Alloy by Shot Peening

摘要

In the present study, a lining process for titanium and its alloy using shot peening was carried out for improving their surface properties. In the shot peening experiment, the metal foil set on the titanium substrate is pelted with many hard shots at a high velocity. The foil is bonded to the surface of the substrate due to plastic deformation induced by the collision of the shots. To assist the bonding, a pure aluminum foil is inserted between the foil and the substrate. The foil and the substrate are heated to heighten the bondability, because the flow stress of the metal is reduced. Lining the substrate with the hard powder sandwiched between two aluminum foil sheets was also attempted. In this experiment, a centrifugal shot peening machine with an electrical heater was employed. The substrates are commercially pure titanium and titanium alloy Ti-6Al-4V, and the foils are commercially aluminum, titanium, nickel and copper. The effects of impact speed and the heating temperature on the bondability were examined. The wear resistance was also evaluated by grinding. The dissimilar material was successfully bonded to the surface of the substrate. It was found that the present method was effective for improving the surface properties of titanium materials.