30 Years of Nanoindentation with the Oliver-Pharr Method and Beyond: Extreme Environments
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Nanomechanical Materials Behavior Committee
Program Organizers: Verena Maier-Kiener, Montanuniversitaet Leoben; Benoit Merle, University of Kassel; Erik Herbert, Michigan Technological University; Samantha Lawrence, Los Alamos National Laboratory; Nigel Jennett, Coventry University

Tuesday 2:30 PM
March 1, 2022
Room: 259A
Location: Anaheim Convention Center

Session Chair: Matt Pharr, Texas A&M University; Samantha Lawrence, Los Alamos National Laboratory

2:30 PM  Invited
Nanoindentations on Nuclear Reactor Relevant Materials: Peter Hosemann1; Stuart Maloy2; Robert Odette3; X Huang1; Jeffrey Bickle1; 1University of California, Berkeley; 2Los Alamos National Laboratory; 3University of California, Santa Barbara
    Materials exposed to nuclear environments face the combined effect of radiation, temperature, corrosion, stress and time contributing to changes in microstructure resulting in materials property changes. Under neutron irradiation materials are activated, while under ion irradiation small volumes are irradiated. In either case it is advantageous to test small volume of materials fostering the need for small scale mechanical testing. Especially indentation-based testing allows for extensive statistics in a short period of time in a cost effective matter. However, the question remains how to relate the obtained nanoindentation data to properties relevant to the operation of the nuclear structure. This presentation features the state of the art of nanoindentation on irradiated materials and how one can obtain relevant bulk properties demonstrated on actual reactor retrieved materials and ion beam irradiated materials.

2:55 PM  Invited
Adapting Nanoindentation for In-situ Electron Microscopy Experiments in Coupled Environments: Khalid Hattar1; Shen Dillon2; Brad Boyce1; Katherine Jungjohann1; 1Sandia National Laboratories; 2University of California, Irvine
    The success of nanoindentation has opened up a world of small-scale mechanical testing in a range of extreme environments. In this presentation, we will highlight the potential of coupled environments during quantitative mechanical experiments. The development of commercial transmission electron microscope (TEM) nanoindentation stages has permitted a range of quantitative indentation, pillar compression, three-point bend, and tensile loading conditions that are predominately limited by the sample preparation technique chosen and one’s imagination. These emerging capabilities permit a vision for in-situ TEM high cycle fatigue, high temperature creep, irradiation induced creep, and stress corrosion cracking. Initial results from the fatigue and creep environments will be demonstrated in materials ranging from high purity metals through scandium stabilized zirconia. Finally, this presentation will highlight the recent developments to explore coupled thermal, mechanical, and radiation environments through SEM scale quantitative mechanical testing. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.

3:20 PM  
NOW ON-DEMAND ONLY - Nanoindentation of Zoned Radiation-damaged Zircon: Micro-pillar Splitting and Mechanical Properties Mapping: Tobias Beirau1; Edoardo Rossi2; Marco Sebastiani2; Warren Oliver3; Herbert Pöllmann1; Rodney Ewing4; 1Martin Luther University Halle-Wittenberg; 2“Roma TRE” University; 3KLA-Tencor; 4Stanford University
    Nanoindentation micro-pillar splitting and high-resolution mechanical properties mapping were employed to measure the fracture toughness (Kc) and to probe the indentation hardness (H) and elastic modulus (E), respectively, of growth zones in radiation-damaged zircon (ZrSiO4) with varying degree of disorder (~45-80% amorphous fraction). The radiation-induced amorphization is caused by α-decay events from incorporated U and Th (~3.7x - 7.5x10^18 α-decays/g). While E and H have found to decrease, Kc increases with the increase in amorphous fraction. As zircon has been proposed as a nuclear waste form for the incorporation of plutonium, a deeper knowledge of the mechanical behavior with increasing structural damage is important, as, e.g., radiation-induced cracking provides diffusion paths for the release of incorporated actinides. Zoned zircon provides a model for the development of multilayer coatings and complex ceramics that can be designed to be resistant to crack propagation and are used in high radiation fields.

3:40 PM  Invited
Indentation Measurements of the Coupled Electrochemical-mechanical Behavior of Materials for Making Better Batteries: Yang Cheng1; 1University of Kentucky
    With an increasing demand for higher energy and power density batteries, the coupled electrochemical-mechanical degradation of battery materials (e.g., electrode and solid electrolyte) becomes a more pressing problem. An improved understanding of the mechanical behavior, which often evolves with the state-of-charge and cycle number, is therefore necessary for improving the performance and durability of batteries. In this presentation, I will provide several examples of using the Oliver-Pharr method and the work of indentation methods to measure the mechanical behavior of battery materials, including silicon/polymer porous composite electrodes, lithium metal electrodes, and ceramic materials for the positive electrode and solid-state electrolyte. Indentation-based methods may also be used to investigate the coupled electrochemical-mechanical behavior of a wide range of materials for making better batteries.

4:05 PM Break

4:25 PM  Invited
Nanomechanics of Materials for High-capacity Rechargeable Batteries: Matt Pharr1; 1Texas A&M University
    Pure metals, such as Li, Na, and K, are ideal anode materials for rechargeable batteries, as they possess the largest theoretical capacities in their respective systems. However, when integrated with liquid electrolytes, these metals readily form dendrites, which lead to severe issues of safety and cyclability. Even when paired with solid electrolytes (SE), several issues still arise, including electrolyte fracture, metal penetration through the electrolyte, and/or loss of anode-electrolyte contact. In this talk, I will discuss our recent experimental studies of the mechanical behavior of several high-capacity electrode materials over various temperatures, strain rates, and length scales (nano to bulk). Of note, through nanoindentation, we find significant size effects in Li, Na, and K. I will then outline the implications of these measurements in terms of stress buildup within metallic protrusions (dendrites) at a SE/anode interface with an eye toward designing safe solid-state batteries with long lifetimes.