Mechanical Behavior of High-Strength Beta-Titanium Alloys.

摘要

Thermomechanical treatments of Beta-III (11.5Mo-6Zr-4.5Sn-Ti) and 18Mo-Ti were performed in order to study microstructure-mechanical property relationships. Transmission electron microscopy was employed to delineate the effects that prior cold work and multiple aging steps produce in microstructure. The optimum combination of strength (230ksi) and good ductility/toughness is obtained by cold work of the Beta-phase followed by preaging in the omega +Beta region and final aging in the alpha +Beta region to produce an extremely fine distribution of alpha-particles in the Beta-matrix. Results of an internal friction study on a series of Beta-Ti alloys containing various amounts of Mo and V with and without plastic deformation are also presented in order to describe the fundamental nature of the Beta-omega transformation. These results indicate the transformation to be of the 'atom shuttle'or displasive type. (Author)