SEM images of the cross section at the topmost surfaces under different burnishing conditions&#46; &#40;a&#41; Burnished at v&#61;30m&#47;min&#44; f&#61;0&#46;05mm&#47;rev&#44; F&#61;200N&#44; n&#61;3&#46; &#40;b&#41; Burnished at v&#61;15m&#47;min&#44; f&#61;0&#46;10mm&#47;rev&#44; F&#61;200N&#44; n&#61;2&#46; &#40;c&#41; Burnished at v&#61;15m&#47;min&#44; f&#61;0&#46;15mm&#47;rev&#44; F&#61;250N&#44; n&#61;3&#46; &#40;d&#41; Burnished at v&#61;45m&#47;min&#44; f&#61;0&#46;15mm&#47;rev&#44; F&#61;200N&#44; n&#61;1 &#40;direction of arrow indicates the top surface&#41;&#46;