Staff engineer, Materials Engineering, The Bendix Corp., Kansas City, Mo.
Member of technical staff, Sandia Laboratories, Albuquerque, N. Mex.
Member of technical staff, Sandia Laboratories, Livermore, Calif.
Pages: 26 Published: Jan 1978
The mechanical behavior of β-extruded Ti-6A1-6V-2Sn has been examined after a variety of subtransus heat treatments. Increasing strength has been found to result in a gradual decrease in fracture toughness. The fracture toughness that may be achieved at any given strength level is also a function of prior solution treatment. Optimum toughness at intermediate strength levels (yield strength of approximately 1035 MPa) is associated with lower solution treatment temperatures, while at high strength levels (yield strength of approximately 1200 MPa), the use of higher solution temperatures appears to enhance the maximum achievable toughness. Comparison of the present results with those previously obtained for α-β processed Ti-6A1-6V-2Sn also indicates that, at any given strength level, β processing will result in a higher fracture toughness and a somewhat lower tensile ductility.
Finally, microscopic evidence suggests that the ordering in the primary α phase which occurs after high temperature aging does not play a predominant role in limiting the fracture toughness of high strength α-β titanium alloys; indeed, the deformation limiting characteristics of the interface α phase may be the principal factor controlling the toughness of these alloys.
titanium, mechanical properties, extrusions, titanium alloys, heat treatment, fracture properties, microstructure, metallography
Paper ID: STP26538S