Cyclic deformation behavior and dislocation substructure in the single crystals of Ti-Al alloy containing 2.0at%Al with double prism slip at different cyclic strain amplitudes were examined. The testing results showed that Ti-2Al displayed an initial slight cyclic hardening followed by a striking softening period, and a saturation stage was reached finally. Secondary cyclic hardening was observed for most specimens before failure, specifically at the high cyclic strain amplitudes. The cyclic resolved shear stress-strain curve was observed to contain a plateau in the testing strain range with a saturation plateau stress of about 55MPa. Trace analysis on the surface of specimens with an optical microscope showed that the 10▪0 and 1¯1▪0 double prism slips could be distinguished from the traces on the (00▪1) surface of the fatigued specimens. The dislocation substructure in the fatigued specimens was examined using a transmission electron microscope. The typical dislocation configuration was the saturated dislocation bundles, which were tangled on the (10▪0) and (1¯1▪0) slip planes and arranged parallel to the [00▪1] direction.

Cyclic Deformation Behavior and Dislocation Structure of Ti-2at%Al Single Crystals Oriented for Double Prism Slip. L.Xiao, Y.Umakoshi: Metallurgical and Materials Transactions A, 2004, 35[9], 2845-52