Nix Award and Lecture Symposium: Recent Advances in Nanoindentation and Small-Scale Mechanical Testing: Nix Award II
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Nanomechanical Materials Behavior Committee, TMS: Mechanical Behavior of Materials Committee
Program Organizers: Wendelin Wright, Bucknell University; Gang Feng, Villanova University

Wednesday 8:30 AM
March 2, 2022
Room: 259A
Location: Anaheim Convention Center

Session Chair: Wendelin Wright, Bucknell University; Gang Feng, Villanova University; Kevin Hemker, Johns Hopkins University


8:30 AM  Invited
2021 William D Nix Award Lecture: Nanoindentation - The Next Generation: George Pharr1; 1Texas A&M University
    Since its introduction and development more than three decades ago, nanoindentation has gained widespread acceptance as a tool for measuring and mapping the mechanical properties of thin films, thin surface regions, and small volumes of material. Hardness and elastic modulus are the most routinely measured properties, but techniques have also been developed for estimating fracture toughness, yield stress, strain hardening, creep, strain rate sensitivity, and residual stress. Many of these can be determined from indentations only a few nanometers deep. After briefly reviewing the early history of its development and the crucial roles played by Professor Nix and his colleagues, this presentation will focus on new and emerging nanoindentation measurement tools and techniques. Special attention will be given to recent efforts to perform fully instrumented nanoindentation at very high strain rates in the ballistic range, and new aspects of small-scale mechanical behavior that can be gleaned from multiaxial nanoindentation testing.

9:30 AM  Invited
NOW ON-DEMAND ONLY - Correlating the Small Scale Mechanical Behavior and the Evolving 3D-microstructure by In Situ Laue Tomography: Jean-Baptiste Molin1; Patric Gruber1; Jean-Sebastien Micha2; Christoph Kirchlechner1; 1Karlsruhe Institute of Technology; 2ESRF
     Interlinking the mechanical properties of materials to their underlying and evolving microstructure is vital for a mechanism-based understanding of deformation, in particular at the micron scale. Numerous characterization tools, like SEM, TEM as well as synchrotron based Laue microdiffraction (μ Laue) offer a complementary toolbox being well suited to answer most questions in material science today. However, the current toolbox is either limited to surface information (e.g. SEM), thin samples (TEM) or integrated information (μ Laue). Also, the precision in determining the local strain tensor by the aforementioned techniques is, for most applications, insufficient.To close this gap, we have combined a DAXM setup with a nanoindenter at BM32 of the European Synchrotron (ESRF). Subsequently, we applied this new instrument to understand the deformation behaviour of 5µm sized bi-crystalline cantilevers by analysing the storage of dislocation in 3D and the local deviatoric (elastic) strain distribution.

10:00 AM Break Coffee Break

10:30 AM  Invited
Nanoindentation as a Reliable Tool for Measuring Surface Free Energy Over Five Orders of Magnitude: Edoardo Rossi1; P. Sudharshan Phani2; R. Guillemet3; Julie Cholet3; Doriane Jussey3; W.C. Oliver4; Marco Sebastiani1; 1Roma Tre University; 2International Advanced Research Centre for Powder Metallurgy & New Materials (ARCI); 3Thales Research & Technology; 4KLA Corporation
     Surface Free Energy (SFE) has become a relevant design parameter for producing materials and devices with controlled wettability in a wide range of applications, where spatially resolved control of surface properties has become a key enabling technology.In this presentation, recent progresses are presented on the adoption of nanoindentation to measure adhesive forces over small nano-engineered surfaces, in controlled environmental conditions, with an accurate account of instrumentation issues. A novel method to measure SFE over five orders of magnitude is validated on surface treated and nano-patterned surfaces. Its limitations and shortcomings are critically discussed in the context of relevant applications: from complex-geometry contacting surfaces in controlled environmental conditions, the time-dependent measurement of functionalization processes, to smart micro- devices with tuned surface properties. The enabling synergistic context of modelling, characterization, and advanced manufacturing is discussed.

11:00 AM  Invited
Size Effects in the Plastic Deformation and Fracture of Strontium Titanate: Karsten Durst1; Javaid Farhan2; Xufei Fang1; 1TU Darmstadt; 2National University of Sciences and Technology, Islamabad
    Strontium titanate, SrTiO3, is one of the functional oxides which, in its single crystalline form, can undergo macroscopic plastic deformation even at room temperature, unlike other typical oxide ceramics. This makes STO an interesting model material for understanding the deformation mechanism of functional oxides, which are the basis for various advanced electronic devices. Here, size effects in plasticity and fracture are investigated using nanoindentation tests with Berkovich and spherical indenters in combination with sequential polishing, chemical etch pit techniques and high-resolution electron backscatter diffraction to quantify the geometrically necessary and total dislocation densities within the plastic zone of the indenter. Nanoindentation load-displacement curves show multiple pop-in events related to nucleation and expansion of dislocation pile-up around indentations, followed by nucleation of cracks. In the presentation, we will discuss the dislocation mechanism leading to different indentation size effects for spherical and Berkovich indentation.

11:30 AM  Invited
Nanoindentation in an Electrochemical Cell: Electro-chemo-mechanical Coupling: Erica Lilleodden1; 1Helmholtz-Zentrum Geesthacht
    Novel nanostructured materials – especially those exploiting high specific surface area and size effects via unconventional structural geometry - go beyond functions predicted by conventional models of mechanical response. Yet to discern these unique functionalities, nanomechanical approaches are needed. In this presentation we consider the influence of electrochemical potential on the mechanical response of nanoporous materials by using a modified electrochemical cell coupled to a nanoindenter. Comparison to results from macro-mechanical testing methods point to the unique role micromechanical testing plays in identifying fundamental relations between microstructural characteristics and the functional response of materials. Examples of such materials including nanoporous gold and nanoporous Si will be presented in terms of the influence of length-scale, structural geometry and electrochemical potential on the mechanical response.