Abstract
Three-dimensional (3D) morphology and growth behavior of acicular ferrite formed in low carbon steel weld deposit (0.11%C) was studied by serial sectioning and computer-aided visualization. The specimens taken from the weld deposit were austenitized at 1350℃ and reacted at 570℃ for varying times. The length, width and thickness of individual ferrite plates, measured from 3D-reconstructed images, were ranging from several microns to ∿25μm, less than ∿8μm and from 0.2 to ∿3μm, respectively. The change in the aspect ratio with holding time indicates that the lengthening occurred first and thickening followed after the plate tips impinged mainly on other plates. Multi-variant ferrite plates were observed to be nucleated at inclusions and grow in the specific directions in the matrix, probably keeping a fixed orientation relationship with austenite.
