Mechanical Response of Materials Investigated through Novel In-situ Experiments and Modeling: Session V
Sponsored by: TMS Structural Materials Division, TMS: Thin Films and Interfaces Committee
Program Organizers: Saurabh Puri, VulcanForms Inc; Amit Pandey, Lockheed Martin Space; Dhriti Bhattacharyya, Australian Nuclear Science and Technology Organization; Dongchan Jang, KAIST; Jagannathan Rajagopalan, Arizona State University; Josh Kacher, Georgia Institute of Technology; Minh-Son Pham, Imperial College London; Robert Wheeler, Microtesting Solutions LLC; Shailendra Joshi, University of Houston
Thursday 8:30 AM
February 27, 2020
Room: 32A
Location: San Diego Convention Ctr
Session Chair: Robert Wheeler, Microtesting Solutions LLC; Alessandro Piglione, Imperial College London
8:30 AM Keynote
Microtensile Testing of (fcc) Copper and (hcp) Titanium at Elevated Temperatures: Robert Wheeler1; Adam Shiveley2; Amit Pandey3; Jiashi Miao4; Michael Mills4; 1Microtesting Solutions LLC; 2Shiveley Technologies; 3Ansys Inc.; 4The Ohio State University
As the temperature increases above ambient levels, deformation in metals generally transitions from dislocation glide or twin-controlled mechanisms to diffusion-controlled processes. Where applications for metals involve high temperature tensile loading, it is best to study deformation in laboratory experiments in-situ, under tensile conditions and at temperature. In the present investigation, we carry out small-scale tensile tests on two elemental metals, (fcc) copper and (hcp) titanium. These tests are carried out in-situ within the SEM or Dual Beam FIB where imaging is conducted during quasi-static loading of specimens held at temperatures ranging from room temperature to 500°C. The deformation microstructures are first related to the stress-strain response. The relaxation or creep responses observed during individual hold stages while loading are then interpreted based on an Onset of Plasticity via Relaxation Analysis (OPRA) and referenced to the temperature-stress regimes present in Frost-Ashby Deformation maps.
9:10 AM
A Novel Experimental Methodology and Theoretical Framework for Enabling Macroscopic-like Deformation at the Microscale: Hi Vo1; Evan Still1; Kiet Lam1; Aljaž Drnovšek2; Laurent Capolungo3; Stuart Maloy3; Peter Chou4; Peter Hosemann1; 1University of California, Berkeley; 2Jožef Stefan Institute; 3Los Alamos National Laboratory; 4Electric Power Research Institute
There has been an extensive amount of research in small-scale mechanical testing (SSMT) because of its significant potential in extracting mechanical properties using small-scale samples. Past research has suggested that the extrinsic properties (e.g. size effect, sample-aspect ratios, and experimental constraints) strongly influence the flow stress of small-scale samples. While these studies have furthered our understanding of the complexity of material behavior at the small length scale, they have also raised a recurring question on the maturity of SSMT for engineering applications. Currently, SSMT is unable to directly extract macroscopic-like strain hardening behavior, necking behavior, uniform elongation, and total elongation values in small scale samples. This inability to reliably extract basic mechanical behaviors, representative of macroscopic properties, has stalled the full adoption of SSMT for engineering applications. Our work has successfully addressed this long-standing challenge by introducing an experimental and theoretical approach that enables macroscopic-like deformation at the micro scale.
9:30 AM
Fabrication of Microscale Specimens via Additive Manufacturing for In-situ Mechanical Testing: Soheil Daryadel1; Majid Minary2; 1University of Illinois at Urbana-Champaign; 2University of Texas at Dallas
In situ mechanical testing using SEM has provided powerful characterization methods for a full understanding of the mechanical behavior of metals at small-scale. Micro-pillar compression is one of the most frequently used novel methods to extract the deformation mechanisms. To date, the most common technique for fabrication of micro-pillars is focused ion beam (FIB) milling of the bulk materials (or films), which requires several tens of hours of the equipment time, and the associated expenses. In this presentation, we report on an additive manufacturing (AM) process, termed localized pulsed electrodeposition (L-PED), that enables the fabrication of micro-pillars in a single step at low-cost in the room environment. This process allows direct deposition of micro-pillars in a few minutes to tens of minutes with great control over the microstructure. The micro-scale AM process may be a major step forward in enabling high-throughput investigation of the process-microstructure-property relationship of metals at small-scale.
9:50 AM
In-situ Dynamic Stress Field Detection using 2D Mechanical Raman Spectroscopy: Abhijeet Dhiman1; Hao Wang1; Vikas Tomar1; 1Purdue University
Mechanical Raman spectroscopy has been developed as an analytical method for in-situ of stress induced inside microstructure. Over the years, mechanical Raman spectroscopy has been used for stress detection at a single point. The detection of stress field over an area requires translation of sample using electronics and is limited for steady state experiments. This work involves a unique setup where Raman spectrum is obtained over an area using a two dimensional laser array system with resolution of 5 μm. The reflected Raman signal is collected into a 2D array of optical fibers using a complex optics system. This 2D signal is flattened into a line array which is processed by a Raman spectrometer. This works involve first ever measurement of stress field for varying strain rate.
10:10 AM Break
10:30 AM Keynote
Micropillar Compression Testing with In-situ Raman Spectroscopy to Study Plastic Deformation in Vitreous Silica: Shefford Baker1; Zachary Rouse1; Praveena Manimunda2; Nicole Wiles1; S.A. Syed-Asif2; 1Cornell University; 2Bruker Nano Surfaces
While extensive plastic deformation is possible in silicate glasses at room temperature in indentation or scratch tests, very little is known about the atomic scale mechanisms that control plasticity. We have developed methods for manufacturing millions of high-quality micrometer-scale pillars in vitreous silica as well as specialized equipment for mechanical testing of those pillars in-situ in a Raman microscope. Raman spectra are seen to change significantly with load. A detailed analysis is used to propose a range of atomic mechanisms of both elastic and plastic deformation that is consistent with both the continuum scale mechanical behavior and the shifts in the Raman spectra with load. These results are compared with Raman spectra taken from residual indentations and from hydrostatically compressed glass in-situ. A taxonomy of plastic deformation mechanisms for silicate glasses is presented.
11:10 AM
Temperature Effects in the Microscale Deformability of Yttria Stabilized Zirconia Prepared by Spark Plasma Sintering: Jaehun Cho1; Jin Li1; Qiang Li1; Jie Ding1; Han Wang1; Sichuang Xue1; Amiya Mukherjee2; Haiyan Wang1; Xinghang Zhang1; 1Purdue University; 2University of California, Davis
3 mol % yttria-stabilized zirconia (3YSZ) has been extensively used as a structural material due to high strength and superb fracture toughness. Here, we prepared 3YSZ by means of spark plasma sintering technique to produce ultrafine grains and investigated temperature dependent deformation mechanisms (25 ~ 670 degree C) at microscale using in-situ microcompression tests. Martensitic transformation toughening dominates the mechanical behaviors of YSZ below 400 degree C. However, it is gradually superseded by grain boundary sliding triggered by ultrafine grains above 400 degree C. When tested at 670 degree C, significantly enhanced plastic flow resulting from dislocation activity along with grain boundary sliding was observed.
11:30 AM
Synchronized Indentation and Raman Spectroscopy for Crystal Engineering: Praveena Manimunda1; Manish Kumar Mishra2; Syed Asif1; 1Bruker; 2University of Minnesota
Molecular crystals offer a broad canvas for the design of advanced materials with biocompatibility and unique mechanical properties. Designing such materials demand understanding of both intermolecular interactions and crystal packings. Nanoindentation has become a state-of-the-art method to probe the mechanical properties of molecular crystals, especially pharmaceuticals. However, not as well addressed is the chemical characterization, which is equally important. In this study surface sensitive Raman spectroscopy technique was combined with instrumented indentation to probe the structural origin of elasticity in halogenated N-benzylideneanilines organic crystals. In situ Raman spectra corresponding to δ(C-Cl), aromatic asymmetric in-plane bending δ(C-H) and aliphatic C-H stretching modes revealed how intermolecular interactions such as C−H···N, C−H···Cl, C−H···Br, Cl···Cl and Br···Br perturb during bending. Further, mechanical anisotropy and mechanochemical changes during indentation on piroxicam crystal (an anti-inflammatory drug) studied using Indentation and Raman spectroscopy.