Orientations – perfectly colored

Abstract

The inverse pole figure (IPF) coloring for a suitable evaluation of crystal orientation data is discussed. The major goal is a high correlation between encoding color and crystal orientation. Revised color distributions of the fundamental sectors are introduced which have the advantages of (1) being applicable for all point groups, (2) not causing color discontinuities within grains, (3) featuring carefully balanced regions for red, cyan, blue, magenta, green and yellow, and (4) an enlarged gray center in opposition to a tiny white center. A new set of IPF color keys is proposed which is the result of a thorough analysis of the colorization problem. The discussion considers several topics: ( a) the majority of presently applied IPF color keys generate color discontinuities for specifically oriented grains; ( b) if a unique correlation between crystal direction and color is requested, discontinuity-preventing keys are possible for all point groups, except for {\overline 4}, {\overline 3} and {\overline 1}; ( c) for a specific symmetry group several IPF color keys are available, visualizing different features of a microstructure; and ( d) for higher symmetries a simultaneous IPF mapping of two or three standard reference directions is insufficient for an unequivocal orientation assignment. All color keys are available in MTEX, a freely available MATLAB toolbox.