MICROSTRUCTURE AND MECHANICAL PROPERTIES OF COLD-DEFORMED PURE TITANIUM AND TITANIUM GRADE 5

Abstract

The effects of cold deformation on commercially pure titanium Grade 2, titanium Grade 4 and titanium Grade 5 (TiA16V4) were explored and compared. The possible use of these wrought materials is discussed. They were worked by rotary swaging at ambi-ent temperature. The purpose was to impart high strengthening, while maintaining sufficient ductility for further processing. The two pure titanium grades were cold deformed with a total area reduction of 90 %. Only minor surface damage was observed on the workpieces. However, in titanium Grade 5, the need for in-process annealing between the cold-deformation steps was identi-fied. High strengthening was obtained in all the materials. Titanium Grade 4 and the titanium alloy had ultimate strengths in ex-cess of 1000 MPa and 1400 MPa, respectively. The hardness profile in the transverse direction was measured and discussed. The interior of the wires had higher hardness than the surface. The microstructure investigation helped to reveal structural changes and clarify the material’s properties.