Rapid solidification processing of titanium alloys

Abstract

This review surveys rapid solidification (RS) processing of titanium alloys. The attributes of and requirements for RS are discussed along with techniques of RS including powder, flake, fibre, and wire production. Compaction and processing techniques are presented followed by a description of the metastable constitutional effects which can result from RS – solid solubility extension and formation of metastable crystalline, quasicrystalline, and amorphous phases. The microstructures that can develop through RS, and their potential subsequent decomposition, are discussed. Effects of additions of dispersoid forming elements, metalloids, and eutectoid formers to enhance mechanical property behaviour are described. The final section deals with the impact of RS on titanium base intermetallics. Throughout the review, the emphasis is on the correlation of microstructures with properties and it is shown where advantages are to be gained from the RS approach compared with conventional ingot metallurgy techniques. Although there are advantages to be gained by RS processing for the titanium system the enhancements in behaviour have not yet been shown to be as great as in other systems such as aluminium; however, it is clear that further work is required to define fully the potential of RS processing of titanium based alloys.