Fully automated orientation relationship calculation and prior austenite reconstruction by random walk clustering

Abstract

Abstract. Two new methods, one for determining the experimentally observed Orientation Relationship (OR) and another for reconstructing prior austenite phase, are proposed. Both methods are based on the angular deviation of the OR at the grain boundaries. The first algorithm identifies the optimum OR using the misorientation distribution of the entire scan i.e. without manual selection of parent grains. The second algorithm reconstructs the parent phase using a random walk clustering technique that identifies groups of closely related grains based on their angular deviation of the OR.

Effect of ausforming and cooling condition on the orientation relationship in martensite and bainite of low carbon steels

“…The selected tolerance ε should be a compromise between the significance of the misorientation data and necessity to exclude random boundaries from the analysis. As it was noted above, the present method is similar to that suggested by Gomes and Kestens [18]. The latter method is yet only briefly outlined in [18], and thus one cannot judge the similarity and difference of the techniques.…”

“…As it was noted above, the present method is similar to that suggested by Gomes and Kestens [18]. The latter method is yet only briefly outlined in [18], and thus one cannot judge the similarity and difference of the techniques. In our calculations ε was chosen so that not less than 90% of actual boundaries have been included in the procedure.…”

“…Recently this approach has been employed to determine OR in the bainite of rolled microalloyed steel [17]. Notice also that it apparently is very close to the method suggested by Gomes and Kestens [18]. Such an approach filters off influence of orientation gradients in deformed γ grains, whereas account for all the revealed boundaries notably increases significance of the derived OR.…”

Development of crystallographic texture under plane and shear strain in ultrahigh-strength strip steels

“…Although the exact parallelism of planes and directions of the K-S OR cannot be observed in actual crystallographic measurements of martensite, the consistent variant labeling system by Morito et al [12] has been used to successfully characterize a number of martensitic/bainitic microstructures with varying orientation relationships between fcc and bcc structure. In the second step, the grain map was divided into discrete clusters using the Markov clustering method [13] proposed by Gomes and Kestens [14]. The parent austenite orientation was then calculated for each cluster separately, resulting in a reconstructed orientation map.…”

Micro-Texture Analyses of a Cold-Work Tool Steel for Additive Manufacturing

“…In this study, quantitative micro-texture analyses using electron backscatter diffraction (EBSD) were performed on the powder and the AM objects of a cold-work tool steel. In order to gain an explicit correlation between the microstructures and process conditions, a recent technique for the reconstruction of prior austenite grains [26][27][28] was utilized. Thus, this study could provide a useful example of the procedures to characterize the microstructures of tool and other martensitic steels for AM.…”