Monotonic and cyclic behavior of Ti-2.5Cu alloy at room temperature (293 K) and at 77 K

Tensile test and low-cycle fatigue tests were conducted with samples of annealed Ti-2.5Cu alloy at 293 and 77 K. The result shows that Ti-2.5Cu alloy possesses higher strength and ductility at 77 K than at 293 K, The longer low-cycle fatigue life at 77 K was obtained for Ti-2.5Cu alloy due to its higher ductility at cryogenic temperature. At 293 K, the dislocation substructures imply that slipping is a predominant deformation mode in either monotonic or cyclic deformation. As temperature decreases to 77 K, the twins observed in the microstructure show that twinning becomes the main deformation mode, and parallel 110 11 type twin was determined in the Ti-2.5Cu alloy. (C) 2002 Elsevier Science B.V. All rights reserved.