Develop Ultrafine Grain Size Titanium with Improved Mechanical Properties.

摘要

Modified Kahn-type tear tests and fatigue crack propagation tests were conducted to evaluate the effect of strengthening by grain refinement and/or cold deformation on the toughness of alpha titanium. In addition to grain size and cold work,the effects of interstitial content,texture,and substitutional alloying were evaluated. For unalloyed materials,the tear strength and the fatigue crack propagation rates were generally improved with increasing yield strength,independently of the chemical and structural conditions. Ti-6Al-4V and Ti-5Al-2.5Sn alloys showed reduced tear strengths. Measurement of the unit propagation energy during tear testing was found to be very sensitive to differences in chemistry and structure. (Modified author abstract)