Pure Titanium And Dynamic Compression Force Shear Deformation Behavior Research

Industrial pure titanium (TA2) has been investigated in the paper. Cylindrical and hat-shape specimens cut with the cylinder axes along the Annealed pure titanium sheet’s0°to the direction of rolling direction (RD-0°),45°to the direction of rolling direction (RD-45°) and90°to the direction of rolling direction (RD-90°). The quasi-static and dynamic compressive mechanical properties of annealed pure titanium sheets were investigated by means of Instron apparatus and Split Hopkinson pressure bar technology. The deformation behavior, microstructure evolution and its anisotropy were studied using optical microscope (OM), transmission electronic microscope (TEM) and electron backscatter diffraction (EBSD).The results show:It is a greater impact for the mechanical behavior of pure Titanium in high strain rate deformation to initial texture and twin. When forced shear deformation, commercially pure titanium s main deformation mechanism is the prismatic slip and pyramidal slip in the shear band region, and the main deformation mechanism is the prismatic slip and twinning out the shear band region. The rotational dynamic recrystallization (RDR) mechanism can explain the fine equiaxed grain formation in ASB. Thermodynamic calculations and electron diffraction spot calibration results show that the phase transition did not occur in ASB.The quasistatic and dynamical compressive mechanical properties show anisotropy:both the yield strength and flow stress for the RD-90°direction sample are the maximum at low strain degree, while those for the RD-0°direction are the minimum in quasistatic deformation. The dynamic and dynamic forced-shear behavior have same rule. Taking into account of crystal orientation distribution of polycrystalline pure titanium sheet, the mechanical anisotropy of titanium sheets could be explained qualitatively based on the microscopic crystal plasticity theory.Different directions on the microstructure presents different:the width of band for the RD-90°direction is most wide, while that for the RD-0°direction is the minimum; grain deformation degree and twin phenomenon for the RD-90°direction are more violent than the other two direction..Micro-hardness from shear zone center outward show decreasing trend, in the shear zone area, twin density has great effect on hardness, the grains away from the deforming area similar to original state. Different directions on the micro-hardness showed obvious different.The author would like to thank the powder metallurgy institute national key laboratory (NO.2008112047) for the financial support.