A Laboratory Experience With Thermal Gradients

An understanding of the behavior of materials at elevated temperatures is a critical component of the education of engineers. Engineers of most disciplines will encounter elevated temperature environments in either the performance aspects of systems they employ and deliver or in the processing of components of systems they are attempting to produce. Sadly, few laboratory experiences that treat elevated temperature behaviors are available, fewer yet really treat the thermal gradients present in these environments or their inherently dynamic nature. This paper describes the development and implementation of a laboratory experience to improve undergraduate students understanding of complex issues related to mechanical behavior in the presence of thermal gradients. Laboratory procedure for the experiment is described in detail. The laboratory allows students to observe changes in the mechanical properties of materials as a function of temperature, thermal gradient and strain rate. Those rare experiences with materials at high temperatures previously available to students typically stress the need for uniform temperatures throughout test samples. This obfuscates critical information, as there are few, if any, processes or applications operating at elevated temperatures where thermal gradients are absent. Students are able to observe materials in the dynamic and non-equilibrium environments encountered in actual service and processing conditions, rather than in the equilibrium or otherwise artificial contexts discussed in the classroom or specially created in the laboratory. The laboratory discussed presents theory and application in a linked fashion. The paper discusses the exceptionally positive impact that this immediacy has an on student learning.