Superalloys: methodological aspects of thermal analysis

A notable number of scientific works aided by thermal analysis methods are available in the literature concerning superalloys. The most frequently applied techniques are DSC, DTA, and TG. Although types of thermal effects investigated by various authors are limited, it is not difficult to find debatable interpretations of curves and characteristic temperatures, even in the case of recent papers. This circumstance was motivation for the work. In this study, basing on literature data and own experiences, we would like to discuss some methodological aspects of thermal analysis. This need results from multiplicity of ways that different authors determine the same characteristic temperatures. The research involves interpretation of heating and cooling curves (DTA, DSC) in view of determination of characteristic temperatures (solidus, liquidus), order–disorder transitions, and other thermal effects typical for Ni- and Co-based superalloys. We discuss different approaches in analysis of thermal effects, present in literature data, and draw the reader's attention to some potential problems related to data interpretation. The intention is to point some disputed methodological aspects and possibly systematize interpretation of effects present in thermal analysis of superalloys.