METHOD OF MANUFACTURING UFG SECTIONS FROM TITANIUM ALLOYS Russian patent published in 2009 - IPC C22F1/18 

FIELD: metallurgy.

SUBSTANCE: invention relates to deformational-and-thermal processing of titanium alloys with a view of a ultrafaintgrain (UFG) structure formation. To provide for the structure pre-fragmentation one undertakes high intensity plastic deformation of the alloy by way of repeated bulk forging with the deformation axes shifted to ensure achievement of a cumulative logarithmic deformation degree no less than 3. Bulk forging performance is commenced at a temperature lower than that of polymorphous transformation with the temperature subsequently decreasing to the commencement temperature level. Bulk forging completed, one undertakes thermal treatment with the temperature stagewise decreased from a value below the recrystallisation threshold to the room temperature level and the deformation degree stagewise increased to a value determined by the thermomechanical treatment kind. Thermomechanical treatment is performed in various combinations: draw forging, rolling, draft, relative deformation degree occasionally being as large as 98% with the plasticity margin preserved. Selection of methods depends on the preset properties of the section material and the latter's configuration.

EFFECT: proposed invention enables industrial-scale production of UFG sections from titanium alloys characterised by a wide range of available geometric parametres and high-grade physico-mechanical properties.

6 cl, 2 tbl, 2 ex