Orientation Determination by Continuous Etching Patterns in Copper and Copper Alloys

Abstract

A new method for determination of grain orientations using etch patterns was developed for copper and copper alloys. This method is based on the fact, that one gets etch patterns characteristic for the crystallographic orientation of the etched surface, if a specimen of copper or copper alloys is etched in conc. HNO3. In contrast to etch pits, the etch patterns are developed continuously over the whole grain. This allows a direct and continuous observation of the orientation changes within and between the grains, which is not possible for many other orientation determination methods. The determination accuracy of the new method depends on the crystallographic orientation of the etched surface and varies between 2° and 10°. For some special surface orientations the etch patterns allow even the determination of very small orientation changes (≤ 2°), occurring e.g. in a deformed grain.