Abstract
Computer image processing technology has been applied to fracture surface analysis, and the generalized software for 3-dimensional fractography -image analysis has been developed. By this software, it became possible to obtain 3-dimensional fracture surface topography from a stereo-pair of SEM fractographs with sufficient precision. As for the identical position search algorithm to calculate the fracture surface height, the SSDA method was fitted to fatigue fracture surfaces in air and in vacuum. Whilst the correlation method must be applied to the corrosion fatigue fracture surface being adhered corrosion products or calcareous deposits on it, as well as to the inter- and transgranular mixed one. The crack closing simulation by means of the 3-dimensional fracture surface topography accounted for the wedge effects induced by the corrosion products or deposits as a first approximation. And the results was corresponded to the shape of load-strain hysteresis loops well. On the contrary, fracture surface roughness deduced from the 3-dimensional topography was not necessarily corresponded to the crack closing behavior.
