Planar Anisotropy, Tension-Compression Asymmetry, and Deep Drawing Behavior of Commercially Pure Titanium at Room Temperature

摘要

The planar anisotropy (PA) and tension-compression asymmetry (TCA) of the CP-Ti were investigated via uniaxial tension and compression tests at room temperature. The formability and the earing behavior of the CP-Ti sheet were studied via deep drawing experiment. The deep drawing simulations using the uniaxial tensile and the compressive curves as the hardening rules were compared with each other and with the experimental results. The CP-Ti sheet showed PA and TCA in yielding and strain hardening. The PA was characterized by the plastic strain ratio r(0), r(45), and r(90) of 1.47, 2.06, and 2.05. The TCA showed PA, which showed tension-compression yield strength ratios of 1.12, 1.08, and 1.04 in 0 degrees, 45 degrees, and 90 degrees in the rolling direction, and tensile and compressive hardening exponent ratios of 0.86, 0.8, and 0.62. The orientation distribution functions (ODFs) analysis demonstrated that the tensile and the compressive deformation textures were different and showed PA. The simulative results, including the simulated forming force and the earing profiles using the uniaxial tensile and compressive curves as the hardening rules, were not in agreement with each other. The results were not in good agreement with the experimental results, implying that the TCA had an important effect on the formability of the sheet. The TCA tended to reduce the thickness of the deep drawing parts, increase the earing ratio, and affect the drawing force.