Development of Ultra Fine Grain Size Titanium with Improved Mechanical Properties

摘要

A two-part study of the effects of interstitial content, grain refinement and cold working on the mechanical properties of titanium-base materials was conducted. In the first part techniques were developed to refine the grain size of Ti-5Al-2.5Sn into the range of 0.5 microns, grain growth kinetics were evaluated and room temperature tensile behavior was investigated. In the second part of the program the effects of grain size and cold work on the room temperature toughness of Grade 3 unalloyed titanium sheet were investigated. Notched tensile, modified Kahn-type tearing, and fatigue crack propagation tests were employed. Strength increases were found to correspond to improved tear strength and reduced fatigue crack propagation rates while other toughness parameters were generally raised to some extent by grain refinement and lowered by cold working. (Author)