RI 7949 Room Temperature Tensile Properties of Titanium and Seven Titanium Alloys Prepared by Skull Casting

The room temperature tensile properties of commercially pure titanium and seven titanium alloys prepared by skull casting were determined in the as-cast and heat-treated conditions. Data were compared with property data from tensile tests on wrought alloys of the same compositions in the as-worked and heat-treated conditions. The alloys evaluated were Ti-5Al-2.5Sn, Ti-6Al-4V, Ti-6Al-4V-lSi, Ti-6A1-2Sn-4Zr-2Mo, Ti-6A1-6V-4Zr-4Mo, Ti-6A1-6V-2Sn, and Ti-11.5Mo-6Zr-4.5Sn. Test specimens were prepared from both static and centrifugal castings and from plate fabricated by forging and rolling vacuum-melted ingots. The data indicate that the alpha and alpha-beta alloys have strength properties in the as-cast condition that are reasonably close to the strength properties of their wrought counterparts in the as-worked condition. An exception to this was the Ti-6A1-6V-4Zr-4Mo alloy for which insufficient data were available to form any firm conclusions. Fine-grained cast structures of Beta III (Ti-11.5Mo-6Zr-4.5Sn) were shown to be generally stronger in the as-cast condition than the wrought alloy in the as-worked condition except for the yield strength of one structure that was unusually low. Heat treatment of this alloy produced properties that were unpredictable. Indications are, however, that optimization of heat treatment parameters for each cast structure could produce strength properties equal to that of wrought materials.