Advanced Characterization Techniques for Quantifying and Modeling Deformation: Session V
Sponsored by: TMS Extraction and Processing Division, TMS Materials Processing and Manufacturing Division, TMS Structural Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Materials Characterization Committee
Program Organizers: Rodney McCabe, Los Alamos National Laboratory; Marko Knezevic, University of New Hampshire; Irene Beyerlein, University of California, Santa Barbara; Wolfgang Pantleon, Technical University of Denmark; C. Tasan, Massachusetts Institute of Technology; Arul Kumar Mariyappan, Los Alamos National Laboratory; Olivia Underwood Jackson, Sandia National Laboratories
Wednesday 8:30 AM
March 17, 2021
Room: RM 13
Location: TMS2021 Virtual
8:30 AM Invited
Combining Advanced Characterization Techniques to Rationalize the Multiple Mechanical Behaviors Observed in TRIP/TWIP Ti-alloys: Lola Lilensten1; Yolaine Danard2; Inès Danard1; Raphaëlle Guillou3; Nathalie Bozzolo4; Dominique Thiaudière5; Frédéric Prima1; 1CNRS - IRCP; 2ICMPE ; 3CEA; 4Mines ParisTech - CEMEF ; 5Synchotron Soleil
TRIP/TWIP titanium alloys have attracted a lot of interest, as they enable to reach an unprecedented combination of work hardening and ductility. However, comparison of the compositions proposed in the literature shows that a wide range of mechanical properties is actually obtained, which is not yet fully understood and cannot be predicted by the current design. The combination of advanced characterization techniques, including specific mechanical testing such as cyclic tests, in-situ SEM and EBSD, and in-situ synchrotron XRD, on a few relevant Ti TRIP/TWIP alloys, leads to a better understanding of what makes this family of alloys so diverse in properties. The parameters influencing the work-hardening, such as the type of martensite formed, the type of twinning and the deformed microstructures have notably been investigated. The in-situ approaches and indirect characterizations, like specific mechanical testing or post-deformation observations, are particularly relevant to detect and characterize the reversible stress induced martensite.
9:00 AM
A Study on Migrating Boundary Induced Plasticity Using Atomistic Simulation: Simoon Sung1; Jaehoon Jang2; Hyerim Hwang3; Yanghoo Kim4; Heung Nam Han1; 1Seoul National University; 2Korea Institute of Materials Science; 3Harvard University; 4Korea Institute of Industrial Technology
It is known that a permanent deformation occurs in even a very low-stress state while a solid-solid phase transformation proceeds in metallic materials. A similar phenomenon is also observed during recrystallization and/or grain growth. To explain these phenomena, the concept of migrating boundary induced plasticity (MIP) had been suggested based on the acceleration of Coble creep on migrating boundary. In this presentation, we confirmed the existence of MIP developed during grain growth using molecular dynamics (MD) simulation. To quantify MIP strain, we applied the various stresses, which is a level below the dislocation nucleation, to unit cell consisted of polycrystalline iron and subtract the elastic part from total deformation. The correlation between MIP strain and migrating boundary velocity was analyzed under the various temperature and stress conditions.
9:20 AM
Deformation Behavior and Phase Transformation of Nanotwinned Al/Ti Multilayers: Yifan Zhang1; Qiang Li1; Mingyu Gong2; Sichuang Xue1; Jie Ding1; Jaehun Cho1; Tongjun Niu1; Ruizhe Su1; Nicholas Richter1; Haiyan Wang1; Jian Wang2; Xinghang Zhang1; 1Purdue University; 2University of Nebraska-Lincoln
Nanotwinned Al/Ti multilayers have exhibited size-dependent microstructure evolution and high strength. However, their deformation mechanisms are less well understood. In this work, we investigated the deformation mechanisms of nanotwinned Al/Ti multilayers with FCC/HCP layer interfaces by using in situ micropillar compression tests. Nanotwinned Al/Ti multilayers exhibit compressive strength up to 2.4 GPa and work hardening capability. Post-compression TEM analyses reveal high-density stacking faults and HCP-to-FCC phase transformations in Ti. Molecular dynamics simulations elucidate the mechanisms of deformation-induced phase transformation in Ti and the influence of the collective movement of partial dislocations on the deformability of Al/Ti multilayers.
9:40 AM
Fingerprinting Shock-induced Deformations via Virtual Diffraction: Avanish Mishra1; Cody Kunka2; Marco Echeverria1; Rémi Dingreville2; Avinash Dongare1; 1University of Connecticut; 2Sandia National Laboratories
The current understanding of the operating deformation mechanisms in metallic materials under shock loading conditions relies on in-situ X-ray diffraction (XRD) experiments. While these experiments can characterize the evolution of the defects and phases, a quantitative understanding of the microstructure's contributions is challenging. Large scale molecular dynamics simulations generated shock-deformed microstructures are analyzed using virtual XRD and selected area electron diffraction (SAED) to fingerprint deformation twin, phase transformation, and stacking faults (SFs) in FCC and BCC metals. The correlations between peak intensity, shift, and broadening in SAED and XRD profiles and volume fractions/densities of twins, and phase transformed regions are investigated for shocked single-crystal Cu, Ta, and Fe. The virtual characterization tools enabled fingerprinting of the twinning and de-twinning behavior in Ta, SFs in Cu microstructures, as well as the BCC-to-HCP and reverse phase transformation in Fe. The observed correlation and the ability to fingerprint diffraction patterns will be presented.
10:00 AM Invited
Deformation Behaviour of High-alloy Twinning-induced Plasticity Steels Unravelled by Complementary Local and Integral Methods: Stefan Martin1; Christiane Ullrich1; Christian Schimpf1; Mykhaylo Motylenko1; Anja Weidner1; Horst Biermann1; David Rafaja1; Alexey Vinogradov2; Yuri Estrin3; 1Tu Bergakademie Freiberg; 2NTNU; 3Monash University
A model is presented that accounts for the underlying deformation mechanisms involving slip/twin interaction and offers a constitutive description in terms of the rate of nucleation of deformation twins and their influence on dislocation storage to describe the excel-lent mechanical properties. The framework for the constitutive model is provided by the Kocks-Mecking-Estrin approach. The key parameter, the stacking fault probability, as well as dislocation density, spacing of deformation bands/twins and texture are used. The mod-el was trialled on X2CrMnNi16-7-10 TWIP steel. A range of local and global materials characterization methods (XRD, TEM, ECCI, EBSD combined with acoustic emission data) were employed. This offered insights in temporal variation of the contributions of different deformation mechanisms. It was shown that direct contribution of deformation twinning to overall plastic strain was insignificant and the main effect was of indirect nature, through influence on dislocation glide, and the ensuing effect on the strain hardening.
10:30 AM
Ultrasonic Effects on Plastic Deformation Behavior of TRIP 780 Steel: Jiarui Kang1; Xun Liu1; 1The Ohio State University
Plastic behavior of TRIP 780 steel under the influence of ultrasonic vibration is studied with micro-tensile tests. The gauge length of the specimen is designed at one order of magnitude smaller than the wavelength of ultrasonic vibration. With this configuration, reduction of flow stress is observed as ultrasonic vibration is applied. The softening effect is more significant with increasing ultrasonic amplitude. When ultrasonic vibration stops, residual hardening is observed, i.e., flow stress rises to a level that is higher than the original stress strain curve. Electron backscatter diffraction (EBSD) was used to characterize the microstructural evolution and the result shows superimposed ultrasonic vibration promotes preferential grain re-orientation and modifies geometrically necessary dislocation (GND) density.
10:50 AM
In-situ Shock Stress Field Detection Using Laser Array Raman Spectroscopy: Abhijeet Dhiman1; Ayotomi Olokun1; Nolan Lewis1; Vikas Tomar1; 1Purdue University
Time-gated Raman spectroscopy has been used in the past for chemical analysis at a nanosecond time scale. Based on prior calibration, the Raman spectra can be used to predict local stress on a microscale spot size. In this work, we used a unique setup where multi-spot Raman spectra were obtained over a microstructure using laser array spots on the sample. The excited Raman signal from each spot on the array was collected into a two-dimensional array of optical fibers for simultaneous spectrum analysis by a spectrograph. This technique was used to measure shock wave propagation through 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. The study shows the effects of interface chemistry on stress propagation through the interface.
11:10 AM
Experimental Characterization and FFT-based Modeling of Heterogeneous Deformation in HCP Materials: Behnam Ahmadikia1; Leyun Wang2; Irene Beyerlein1; 1University of California, Santa Barbara; 2Shanghai Jiao Tong University
Active deformation mechanisms and their transmission across the grain boundaries are characterized in several HCP materials, using a combination of electron backscattered diffraction (EBSD) and scanning electron microscopy (SEM). Intense slip bands on prismatic planes and {101 ̅2} 〈1 ̅011〉 tensile twinning were the most common deformation modes observed in soft- and hard-oriented crystals in CP-Ti, respectively. In some adjacent crystals, transmission between the two mechanisms across the grain boundary was presumed. Applicability of the geometric factor m' to describe the transmission is discussed. Having the deformation characteristics identified by the characterization techniques, two full-field fast Fourier transform (FFT)-based calculations, twin-FFT and a novel SB-FFT, are then applied to explicitly model discrete twin and slip bands in crystals, respectively. Consequently, the effect of slip bands and twinning on the local stress fields and their role in slip ↔ twinning transmissions are presented and discussed.