Advanced Real Time Imaging: Mechanical (Joint session with Mechanical Response of Materials Investigated through Novel In-situ Experiments and Modeling Symposium)
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Alloy Phases Committee, TMS: Biomaterials Committee
Program Organizers: Jinichiro Nakano, MatterGreen; David Alman, National Energy Technology Laboratory; Il Sohn, Yonsei University; Hiroyuki Shibata, Tohoku University; Antoine Allanore, Massachusetts Institute of Technology; Noritaka Saito, Kyushu University; Anna Nakano, US Department of Energy National Energy Technology Laboratory; Zuotai Zhang, Southern University of Science and Technology; Candan Tamerler, University of Kansas; Bryan Webler, Carnegie Mellon University; Wangzhong Mu, KTH Royal Institute of Technology; David Veysset, Stanford University
Wednesday 2:00 PM
March 17, 2021
Room: RM 26
Location: TMS2021 Virtual
Session Chair: David Alman, USDOE National Energy Technology Laboratory; Robert Wheeler, Microtesting Solutions LLC
2:00 PM Invited
Real Time Studies of the Mechanics of Spherical Microparticles: Lewei He1; Xuchen Wang1; David Veysset2; Mostafa Hassani1; 1Cornell University; 2MIT
Recent advances in real-time imaging of deformation at microscale have opened unique opportunities for studies of complex behavior of materials. When further combined with computational modeling, a comprehensive understanding of material mechanics and physics can be developed. This talk will survey recent examples where the above nexus proves successful. In the first example, we resolve quasi-static and impact-induced deformations of spherical metallic microparticles using scanning electron microscope and high-speed camera, respectively. We use in-situ observations and finite element simulations to identify material parameters and describe deformation mechanics of the microparticles. Next, we use time-resolved imaging and finite element simulations of metallic microparticles impacting metallic substrates to understand the transition from rebound to bonding. The transition which occurs beyond a threshold velocity is critical for material buildup during kinetic deposition. We develop a unified framework to predict the threshold bonding velocity for different combinations of microparticle and substrate materials.
2:20 PM
Determination of Uranium Oxidation Kinetics Through White-Light Interferometry: Yaakov Idell1; Wigbert Siekhaus1; Kerri Blobaum1; William McLean1; 1Lawrence Livermore National Laboratory
Material degradation of uranium resulting from the uranium-oxygen reaction has long been of great interest to the nuclear industry in hopes of solving long-term storage and disposal related concerns. The mechanisms and kinetics of the early-stage oxide film growth (< 1 µm thick), are not well understood and high-resolution spatial data is essential to understanding changes in the oxide film. We have automated a white-light interferometer, a non-destructive and non-contact optical surface profiling instrument, to rapidly collect in-situ time-dependent three-dimensional measurements of the growing oxide film with nm-scale vertical and µm-scale lateral resolution. We will be presenting the in-situ white-light interferometry results that have been collected in dry air and pure O2 gas environments and at various temperatures, which will be complemented with spectroscopic ellipsometry and X-ray diffraction data. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
2:40 PM
The Accurate Measurement of Elastic Modulus and Hardness of Different Cross-linked SU-8 Polymer: Prakash Sarkar1; Prita Pant1; Hemant Nanavati1; 1Indian Institute of Technology Bombay
SU-8 is an epoxy-based resist involved to design ultra-thick and high aspect ratio micro-electrical mechanical system (MEM)-type applications require accurate values of mechanical properties. Hence, we show interest to measure elastic modulus (Er) and hardness (H) of different cross-linked SU-8 thin film fabricated by standard photolithography process. The cross-linking amount is estimated by in-situ Fourier-transform infrared spectroscopy (FTIR). To measure Er and H, nanoindentation experiments are performed at 800μN load. By following conventional method, obtained Er and H values are high for less cross-linked samples and vice-versa. This is because of adhesion between tip-sample surface, viscoelasticity and wrong contact area (Ac) measurement. After minimizing adhesion and viscoelasticity, residual area of indent impression obtained from scanning probe microscopy (SPM) is considered as Ac. Thereafter, we have obtained accurate values of Er that is 4.61±0.13GPa and 5.02±0.18GPa, and H is 256.97±1.42MPa and 285.48±1.17MPa for less (~82%) and high (~95%) cross-linked samples respectively.
3:00 PM
Lubrication Mechanism of Phosphonium Phosphate Ionic Liquid: a Combined In Situ Atomic Force Microscopy and Ex Situ Surface Spectroscopic Study: Filippo Mangolini1; Zixuan Li1; Oscar Morales-Collazo1; Jerzy Sadowski2; Hugo Celio1; Andrei Dolocan1; Joan Brennecke1; 1University of Texas at Austin; 2Brookhaven National Laboratory
Phosphonium phosphate ionic liquids (PP-ILs) have attracted considerable attention in tribology owing to their high thermal stability, low vapor pressure, good miscibility in hydrocarbon fluids, and excellent lubrication performance. Despite the scientific weight of previous macro-scale tribological studies of PP-ILs, a fundamental understanding of the underpinning nanoscale lubrication mechanism is still lacking. Here, we used atomic force microscopy (AFM) to visualize and quantify the processes occurring at sliding interfaces in situ, in well-defined single-asperity nanocontacts. The AFM experiments, in which a diamond tip was slid on steel in PP-IL, indicated a significant reduction in friction only after the removal of the native oxide surface layer from steel. Based on subsequent laterally-resolved ex situ analyses of the surface chemistry of steel by X-ray photoemission electron microscopy, low energy electron microscopy, and time-of-flight secondary ion mass spectrometry, a simple phenomenological model will be proposed to account for the observed tribological behavior.
3:20 PM Invited
Mapping Local Strains during In Situ SEM Deformation of Nanoporous Materials: Kevin Schmalbach1; Nathan Mara1; Antonia Antoniou2; 1University of Minnesota; 2Georgia Institute of Technology
Porous metallic materials represent a class of materials where the interplay of ligament length, width, node structure, and local geometry/curvature offer a rich parameter space for study of critical length scales on mechanical behavior. Colloidal templating of 3-dimensionally ordered macroporous (3DOM, i.e. inverse opal) materials provides a unique structure for investigation of mechanical behavior at small length scales across the tungsten brittle-ductile transition. Micropillar compression tests show failure at 50 MPa contact pressure at 30 °C, implying a ligament yield strength of approximately 6.1 GPa for a structure with 5% relative density. In situ SEM frustum indentation with in-plane strain maps perpendicular to the loading indicate local compressive strains of approximately 2% at failure at room temperature. Large (20%) nonlocal strains are evident at 125 °C, with a transition to enhanced strength and deformability at higher temperatures.
3:40 PM
Local Shock Viscosity Measurement in Composites Using In-situ Time-gated Raman Spectroscopy: Abhijeet Dhiman1; Ayotomi Olokun1; Nolan Lewis1; Vikas Tomar1; 1Purdue University
Shock viscosity measurement for the material is important to characterize the dissipation mechanism for shock front to reach extreme pressures in a very short period. The shock pressure rise time in a material is correlated to the shock viscosity as a function of strain rate. In this work, a novel experimental setup based on nanosecond time-resolved Raman spectroscopy was used to measure in-situ stress rise due to impact from high-speed microsphere. The Raman spectroscopy was used in combination with a streak camera to obtain nanosecond resolved Raman spectra from a microscale domain to measure local pressure rise time. This technique provides an advantage over free surface velocity measurement techniques such as photon Doppler velocimetry or VISAR where a reflective surface is not available. This technique was used to measure local shock viscosity at the interface between octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and Hydroxyl-terminated polybutadiene (HTPB) binder at strain rates higher than 1e6/s.