Patent ID: 7311873

Claim:
Process of direct powder rolling of blended elemental titanium alloys, titanium matrix composites, and titanium aluminides for manufacturing strips, plates, sheets, foils, and other flat products comprises the following steps: (a) providing a commercially pure (C.P.) titanium matrix powder and at least one powder of alloying components comprising elemental alloying powder or powders, pre-alloyed master alloy powders, and hard reinforcing particles being used to achieve the required chemical composition and/or reinforcement of the final product, (b) mechanically activating and reducing by attrition of all alloying components, whereby the particle size of attrited alloying powders is at least ten times smaller than the particle size of the matrix titanium powder, (c) blending titanium powder as a ductile matrix material with attrited alloying powders obtained in step (b) at the ratio of blended powders that provides the required chemical composition of the final product, (d) cold direct powder rolling of the blend in a mill with horizontally-positioned rolls to achieve density of the rolled strip of 60±20% of the theoretical value, whereby diameters of rolls are different, so that the green strip is bent for the subsequent densification by a second horizontal rolling mill staying in line with the first rolling mill, and rotations of edging rolls of at least one of said mills differ in the rate by 5-15% to promote densification of the green strip by shear deformation, the diameter of the rolls is 40-250 times larger than thickness of the rolled strip, (e) densifying by cold re-rolling of the green strip in a horizontal rolling mill, whereby diameter of the rolls of the densification mill is 1.1-5 times larger than the diameter of rolls of the direct powder rolling mill to provide compressive action and avoid shearing action of the green strip and achieve density of the rolled strip in the range of 90±10% of the theoretical value, (f) multiple cold re-rolling of the strip in vertically-positioned rolls at equal rotation rate of the edging rolls to achieve density of the green rolled strip about 100% of the theoretical value, and (g) sintering of near fully-dense green rolled strip in vacuum, in protective atmosphere batch furnace, or in continuous belt furnace in protective atmosphere.