Continuous Observation of Tensile Deformation of Polycrystalline Titanium by Scanning Probe Microscope

Change in the surface morphology during tensile plastic deformation of polycrystalline titanium with grain size of about 30μm is consecutively observed and measured by the scanning probe microscope. The results show that the surface deformation is mainly due to slip for the plastic strain less than 0.1. After that, a large amount of twins are formed and the second slip system becomes active, and accordingly the surface roughness increases. The roughness, the maximum height difference, and the averaged slope angle of the microscope surface profile increase with the applied tensile strain. The step height of the first slip lines increases, while the spacing between the slip lines decreases with the applied strain. Furthermore, the ratio of the step height to the spacing increases almost linearly with the applied strain. The angle between the slip lines and the load axis decreases due to the rotation of the crystal grain with the applied strain.