Tensile and impact properties of mesoscopic-grained #alpha|#+#beta#-type titanium alloys obtained through hydrogen treatments

摘要

The aim of this investigation was to study the effectof hydrogen treatment on the tensile and impact properties of#alpha|#+#beta#-type titanium alloys. The results were as follows:it was found that mesoscopic-grained Ti-6Al-4V alloys with grainsize 1-3 #mu#m had high ductility together with high strength. Inparticular, it showed an extremely large uniform elongation. Theyield stress of these alloys with grain sizes 1-3 #mu#m increasedlinearly in proportion to the – 1/2 power of grain size. Very finevoids were observed directly below the fractured surface of tensilespecimens with mesoscopic structures. The microstructures ofhighly deformed alloys with mesoscopic structures indicated that afine #beta#(bcc)-phase was dispersed along the boundaries ofequiaxed #alpha#(hcp) grains which were preferentially deformed,similar to the grain-boundary-sliding phenomenon ofsuperplasticity. The impact test indicated that the toughness of themesoscopic-grained alloys was comparatively low. 1999Published by Elsevier Science S.A. All rights reserved.