April 22 - 26, 2024
Seattle, Washington
May 7 - 9, 2024 (Virtual)

Event Supporters

2024 MRS Spring Meeting
SF01.14.03

Thin Film Combinatorial Sputtering of TaTiHfZr Compositionally Complex Alloys for Rapid Materials Discovery

When and Where

Apr 26, 2024
11:00am - 11:15am
Terrace Suite 1, Level 4, Summit

Presenter(s)

Co-Author(s)

Reece Emery1,Stephen Puplampu1,Dayakar Penumadu1,Eric Lass1,Shakti Padhy1,Zachary Sims1,Philip Rack1

The University of Tennessee, Knoxville1

Abstract

Reece Emery1,Stephen Puplampu1,Dayakar Penumadu1,Eric Lass1,Shakti Padhy1,Zachary Sims1,Philip Rack1

The University of Tennessee, Knoxville1
Combinatorially sputtered thin films can be leveraged as a rapid, materials discovery process in mechanical alloy design. Ta<sub>w</sub>Ti<sub>x</sub>Hf<sub>y</sub>Zr<sub>z </sub>thin films were synthesized via combinatorial sputtering from pure Ta, Ti, Hf, and Zr targets. The substrate was not rotated to generate compositional gradients where 12.4&lt;w&lt;71.6, 6.40&lt;x&lt;55.6, 4.22&lt;y&lt;58.8, 7.25&lt;z&lt;48.9 over a 100 mm diameter substrate. The crystal structure, phase fraction, film morphology, mechanical (i.e. modulus and hardness), optical (i.e. n and k), thermal (i.e. phase stability, CTE, and thermal conductivities), and corrosion properties (i.e. corrosion current and rates) are all correlated to the Ta<sub>w</sub>Ti<sub>x</sub>Hf<sub>y</sub>Zr<sub>z </sub>composition. Temperature dependent x-ray diffraction (TDXRD) reveals the thermal stability of the material system. TDXRD has shown the as-deposited material library is primarily stable in a single HCP phase below 60 at. % Ta at room temperature but will form increasing amounts of a BCC phase at elevated temperatures. Nanoindentation of as-deposited films shows good agreement between experimental, solid solution estimations of hardness via a simple rule of mixtures from bulk elements, and correlated to a few up-scaled bulk samples. Thin film modulus shows good agreement with bulk rule of mixture estimations after accounting for thin film substrate effects via King’s correction. As-deposited and annealed film properties are compared. Compositions with an optimal combinations of the aforementioned properties were then upscaled to bulk materials for further investigation.

Keywords

combinatorial | high-entropy alloy | thin film

Symposium Organizers

Ben Breitung, Karlsruhe Institute of Technology
Alannah Hallas, The University of British Columbia
Scott McCormack, University of California, Davis
T. Zac Ward, Oak Ridge National Laboratory

Session Chairs

Alannah Hallas
Cormac Toher

In this Session