DETERMINATION OF FRACTURED STEEL SURFACE-ROUGHNESS BY ATOMIC-FORCE MICROSCOPY USING FRACTAL-BASED APPROACHES

Roughness images of fractured steel surfaces were recorded at micromet ric level (100-10 000 nm) using an atomic force microscope, We have ob served a power law variation of the profile root-mean-square rs. the a nalysis length. If there is no overall tilt of the images, this variat ion is indicative of the (self-affine) fractal character of the surfac e morphology, Using first-principle methods, the fractal dimension of the studied fractured steel surfaces is found to be D = 1.13 +/- 0.06 at the micrometre scale and thus of the same order as previously publi shed values obtained at the centimetre and millimetre scales.