INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Effect of microstructure and stress triaxiality on ductility and toughness in ƒÑ/ƒÒ Ti alloys
Autor/es:
S. KANAMORI; E. ABE; T. TAGAWA; M.D. CHAPETTI; T. MIYATA
Lugar:
San Nicolas, Argentina
Reunión:
Jornada; SAM-CONAMET 2007; 2007
Institución organizadora:
Sociedad Argentina de Materiales (SAM)-CONAMET
Resumen:
The effects of stress triaxiality on the process of micro-void coalescence type of fracture and ductility of a/b titanium alloys with equiaxed a phase were investigated. Materials tested were 3 types of titanium alloys (Ti-6Al-4V, Ti-4.5Al-3V-2Fe-2Mo, and Ti-10V-2Fe-3Al alloys) and two or three different heat treatments were conducted for these three alloys in order to obtain different grain size. Fracture toughness tests were performed and JIC values were evaluated. Correlation between the toughness and the ductility under high triaxial stress state was investigated to clarify factors constructing the fracture toughness. The dependency of the stress triaxiality on fracture strain obtained from the notched round bar specimen were also investigated. It was shown that most of microvoids in a/b titanium alloys were nucleated at a/b interface, and the micro-structural parameter defined as the average distance between a/b interfaces was closely related to the dimple size on the fracture surface. The refinement of microstructure leads to the reduction of ductility and fracture toughness, tough near-b titanium alloys with ultra-fine particle of a (< 1 mm) have exceptionally a different tendency from other a/b titanium alloys. A significant deterioration of the fracture strain with the increase of the stress triaxiality is observed, and it is shown that the strain for the void to grow is relatively small in the higher strength materials.