Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lath Martensitic Steel

18th International Conference on Textures of Materials

材料科学;物理学

Cluff, S.^1 ; Homer, E.^1 ; Nelson, T.^1 ; Song, R.^2 ; Fullwood, D.^1

Department of Mechanical Engineering, Brigham Young University, Provo

UT, United States^1

ArcelorMittal Global RandD - East Chicago Automotive Products, East Chicago

IN

46312, United States^2

关键词: Austenite grain;    Austenite twins;    Lath martensitic steels;    Orientation relationship;    Overlapping regions;    Reconstruction method;    Special boundaries;    Twin boundaries;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/375/1/012012/pdf
DOI  :  10.1088/1757-899X/375/1/012012

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The study of post-transformation microstructures and their properties can be greatly enhanced by studying their dependence on the grain boundary content of parent microstructures. Recent work has extended the crystallographic reconstruction of parent austenite in steels to include the reconstruction of special boundaries, such as annealing twins. These reconstructions present unique challenges, as twinned austenite grains share a subset of possible daughter variant orientations. This gives rise to regions of ambiguity in a reconstruction. A technique for the reconstruction of twin boundaries is presented here that is capable of reconstructing 60°twins, even in the case where twin regions are comprised entirely of variants that are common between the twin and the parent. This technique is demonstrated in the reconstruction of lath martensitic steels. The reconstruction method utilizes a delayed decision-making approach, where a chosen orientation relationship is used to define all possible groupings of daughter grains into possible parents before divisive decisions are made. These overlapping, inclusive groupings (called clusters) are compared to each other individually using their calculated parent austenite orientations and the topographical nature of the overlapping region. These comparisons are used to uncover possible locations of twin boundaries present in the parent austenite. This technique can be applied to future studies on the dependence of post-transformation microstructures on the special grain boundary content of parent microstructures.