Abstract
Change in the surface plastic deformation of polycrystalline titanium with grain size of about 180 μm is consecutively observed and measured by a scanning probe microscope. It is shown 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 secondary slip system becomes active, and accordingly the surface roughness increases. Then, the deformation proceeds with both the slip and the twin in a harmonious way. The surface roughness, the maximum height difference and the averaged slope angle of the microscopic surface profile increase with increase in applied tensile strain. The angle between the slip lines and the loading axis decreases a little with increase in applied strain. It is pointed out that by the use of a scanning probe microscope, the relation between the development of slips or twins in grains and the surface roughness can be clarified in nano-scale.
