Titanium alloys single-phase alpha-alloy VT1, complex-alloyed alpha-alloy ST1, two-phase alloys OT4, VT6S, VT14, and single-phase beta alloy VT15 always fracture on rolling at 500-800C. Bands, similar to macrolocalized strain bands in steel, and cracks are formed by the rolling. The microhardness of these bands, exceeding that of the basic metal, cannot be explained by single strain hardening. The formation of these bands in titanium alloys is attributed to phase transformations in the local heating sites under action of the heat effect. The local overheating causes low heat conductivity in the titanium alloys and more rapid deformation upon rolling. This belief is supported, for instance, by the increased heat effect and increased microhardness observed in VT14 on rolling at the lower temperatures. The structure of the bands, which are arranged diagonally to the cross section of the macrosections, differs from that of the base metal. In addition there are fine bands, also arranged at about 45 degrees to the sample surface. The use of fractional deformations instead of the large deformations usually encountered in thermomechanical treatment is recommended to reduce the probability of forming these bands and microcracks. Author
Unedited rough draft trans. of Fizika i Khimiya Obrabotki Materialov (USSR) n2 p123-125 1967.