Ion Beam Processing in the Sample Preparation for the Analysis of Ductile Damage in Deep Drawing Steels

Abstract

Abstract Ion beam polishing and ion beam etching have proven their worth in examinations for which mechanical and wet chemical methods can not be applied. The analysis of voids in steel microstructures requires a sample preparation which provides for a surface ablation without mechanical impact on the sample surface. Otherwise, smearing effects prevent the revealing of voids. These voids arise during cold forming. They provide information on the ductile damage which is characterized by the formation, growth, and the merging of cavities in the microstructure. Taking the example of deep drawing steels, modified preparation methods for the imaging of microvoids and nanovoids by means of electron microscopy are presented. The specific resulting surface topography, which is influenced by the ion beam's angle of incidence, the accelerating voltage, and the processing time, is examined in a parameter study. It will be analyzed to what extent the relief structures created by ion beam processing are helpful for or interfere with the examinations. In addition to that, their suitability for the interpretation of microstructural processes in the context of the occurrence and evolution of ductile damages is discussed.