Materials science is challenged with developing new materials in order to meet the demands of technological innovation. Consequently, this opens the door to novel or complex properties awaiting exploration. High entropy carbides (HECs) continue to demonstrate the viability of materials engineering using configurational entropy to aid in phase development. Using two compositions, Hf-Nb-Ta-Ti-Zr-C (HEC3) and Hf-Mo-Ta-W-Zr-C (HEC6), we explore the thermal transport properties of these systems as carbon stoichiometry is varied. Using time domain thermoreflectance (TDTR), we measure thermal conductivity of both the HEC3 and HEC6 thin film series and then relate trends to other observed characteristics of each system such as electrical conductivity, crystallinity, and modulus. Total thermal conductivity systematically varies with increasing deposition flow rate of methane, while the electrical contribution to the thermal conductivity decreases. Results are discussed in terms of various scattering mechanisms from different types of defects, emphasizing understanding of thermal properties from both a local and a global structural perspective. In this talk we focus on the experimental process of elimination using several metrology techniques in conjunction with TDTR to gain meaningful perspective on configurationally disordered, highly crystalline systems.
5:00 PM–7:00 PM Apr 23, 2019 (US - Arizona)
PCC North, 300 Level, Exhibit Hall C-E