两种位向关系的描述方法的转换及其应用

CONVERTION AND ITS APPLICATION OF TWO KINDS OF DISCRIPTIONS ON THE ORIENTATION RELATIONSHIP

本文推导了表征两套晶格间的位向关系的标识矢量方法到Euler角方法的转换关系,基于这个关系可以根据背散射电子衍射(EBSD)数据对少变体的系统进行拟合,获得各变体相互自洽的位向关系精确定量描述.本方法比高指数极图拟合的方法适用性更广,因为后者受最低变体数量的局限.以不锈钢的实验结果为例介绍了该方法的应用,检测出变体之间接近但不等于孪晶的取向差关系.

In fcc/bcc phase transformation systems,the orientation relationships（ORs） are usually described by parallelism of a set of specific vectors pairs or small deviations from the parallelism. This method often reflects the characteristic feature of the phase transformation correspondence.With the application of the electron backscatter diffraction（EBSD） technique to the measurement of the ORs, the ORs are also evaluated by a rotation matrix or a group of Euler angles.However,this quantitative description does not provide an intrinsic relationship between the crystallography equivalent variants. Thus,self-consistency of the data from different variants with an identical OR is not reflected directly by the data.In this paper,formulas have been derived to convert the OR identified by the relative orientation of a specific set of vectors to the OR described by Euler angles in data from EBSD.This method is useful for acquiring self-consistent OR of small number of variants.Compared with the fitting method using high-indexed pole figures,which requires existence of many variants,the present method has broader applicability.An application example is given to determine the OR between two phases in a duplex stainless steel from the measurement data of two variants.A slight deviation from an exact twin relationship between the variants has been characterized