Three-dimensional morphology of grain boundary Widmanstätten ferrite in a low carbon low alloy steel

The three-dimensional morphology of austenite grain boundary Widmanstätten ferrite in a low carbon low alloy steel was revealed by means of serial sectioning in conjunction with computer-aided three-dimensional reconstruction techniques. Primary and secondary Widmanstätten sideplates are better described to be wedges instead of plates. Primary Widmanstätten sawteeth appear to be spikes or triangular cones whereas secondary Widmanstätten sawteeth have the shape of elongated spikes or triangular cones. These results indicate that the three-dimensional shape and connectivity of grain boundary Widmanstätten ferrite are different from those deduced on random planar sections by two-dimensional microscopy.