純チタン薄板における微視的な不均一変形が表面あれに及ぼす影響に関する結晶塑性有限要素解析

Pure titanium has been widely used as one of the primary metals in aerospace and biomedical fields for the last few decades, since the strong demands for the light weighted and strong materials have been increasing in the fields. Despite the great enhancements, pure titanium is still one of the difficult materials to predict the deformation behaviors. To study the effects of complicated microscopic non-uniform deformations on the surface roughness, a uniaxial tensile deformation of poly-crystalline pure titanium sheet by finite element analysis based on the crystal plasticity theory was conducted in the present work. It was found that the microscopic deformations around 0.2% strain range decided the surface roughness and the approximate surface’s shapes of the present material. In other words, the surface roughness of the pure titanium was determined by the deformation at the small macroscopic strain around 0.2%, rather than, that at the macroscopic larger strain. The subsequent deformation after 0.2% strain could only rescale the size of the surface roughness without any further changes in the shape of surface roughness.