PI: Julian Escobar Atehortua (Formerly Scott Whalen)

Measuring temperature profiles during SPP of metals is of fundamental interest to understand, control, and optimize microstructures produced via dynamic recrystallization. However, sensing temperature within deforming materials is extremely difficult. During shear assisted processing and extrusion (ShAPE), the stirring microstructure cannot be directly reached with conventional contact thermocouples as the extruding volume is confined inside an extrusion die. At the Pacific Northwest National Laboratory, we are currently working on the direct measurement of temperature profiles within a deforming metal using thermo-electric potentials. The voltage difference across two dissimilar materials that make contact during deformation can be translated into temperature through calibration of the Seebeck coefficients for each metal. This approach has been successfully applied to measure the internal temperature within the deformation zone during ShAPE of Al1100. Temperature profiles at different feed rates have been measured, allowing for a more detailed understanding of the processing-microstructure relationship during ShAPE.