Frank Stein

Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany

Abstract

As we have learned in the preceding lectures, diffusion couples can be used to produce extended zones of material with a concentration gradient that covers the entire composition range of a phase. In addition to determining the homogeneity range of phases and extracting interdiffusion coefficients, this graded material can be studied by employing various types of micro-scaled testing methods and performing measurements along the concentration gradient to scan properties as a function of composition. Regarding mechanical properties, this can be done most easily by nanoindentation to determine hardness as a function of composition. Moreover, strength and fracture toughness can be investigated by cutting series of micropillars and microcantilevers, respectively. In addition to mechanical behavior, it is also possible to study various kinds of physical properties such as thermal and electrical conductivity as well as magnetic or optical properties. Some examples of such kind of experiments are presented and the advantages compared to classical testing methods are discussed.