Advanced Characterization Techniques for Quantifying and Modeling Deformation: Session VII
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
Thursday 8:30 AM
March 18, 2021
Room: RM 13
Location: TMS2021 Virtual
8:30 AM
Materials Processing in a Synchrotron Beam: Klaus-Dieter Liss1; 1Guangdong Technion - Israel Institute of Technology (GTIIT)
The real-time and multi-dimensional detection of diffractograms of high-energy synchrotron X-rays bears the advantage to follow grain orientations and their statistics in-situ in reciprocal space. Small scattering angles bear the advantage of pencil probing upon in-situ physical thermo-mechanical simulation. The morphology of Debye-Scherrer rings depends on grain and subgrain arrangements, while their change gives insight into processes as grain coarsening or refinement, grain rotation, slip systems, static and dynamic recrystallization, and phase transformation. Activation temperatures can be read from time-resolved studies upon heating. Special cases on metallic material system will be discussed in the presentation, together with an outlook into future directions.
8:50 AM
On the Coupled Effects of Hydrogen Diffusion and Hydride Precipitation in Zirconium Alloys: Alireza Tondro1; Hamidreza Abdolvand1; 1Western University
Hydrogen diffusion directly affects the lifespan and in-service performance of nuclear reactor core components. The state of stresses is one of the main factors in hydrogen redistribution. This study uses a coupled mass diffusion and crystal plasticity finite element approach to simulate the hydrogen distribution as a result of localized stresses that develop during external loadings and formation of hydrides. The effects of hydride induced transformation strain on hydrogen distribution are studied using different cases of intergranular and intragranular hydrides. Results suggest that, due to hydrostatic stresses, the highest and lowest hydrogen concentrations take place respectively at the hydride tips and hydride sides. This results in axial propagation of hydrides. Also, hydride tips in the vicinity of harder grains are more probable to grow. The interactions between hydrogen diffusion and deformation twins are also studied where the results show that hydrogen atoms tend to diffuse towards the twin tips.
9:10 AM
Crystal Plasticity-based Modelling of Taylor Impact Test of Single Crystal Tantalum: Zhangxi Feng1; Miroslav Zecevic2; Ricardo Lebensohn2; Marko Knezevic1; 1University of New Hampshire; 2Los Alamos National Laboratory
Tests carried out for Ta single crystal cylinders impacted along different crystallographic directions showed strong variations in dimensional changes for different orientations [1]. In order to capture the strong effect of crystallography on the deformation mechanisms and final shapes of the impacted cylinders, a polycrystal plasticity material model based on the viscoplastic self-consistent (VPSC) formulation was adapted to single-crystal material points and embedded in solid mechanics/dynamics solvers to simulate the aforementioned single-crystal Ta Taylor anvil experiments. Details of the coupled model implementation and insights on the role of single-crystal anisotropic flow on the deformation behavior under extreme mechanical and adiabatic heating conditions across a broad range of strain-rate and temperatures will be presented and discussed. [1] H. Lim et al: “Anisotropy and strain localization in dynamic impact experiments of tantalum single crystals”. Scientific Reports 8, 5540 (2018).
9:30 AM
Slip-twin Transfer Across Phase Boundaries:
An In-situ Investigation of a Ti-Al-V-Fe (α+β) Alloy
: Shaolou Wei1; Gaoming Zhu1; Cem Tasan1; 1Massachusetts Institute of Technology
The predominant role of heterogeneous deformation incipience and its transfer across grain/phase boundaries have been recognized in various macroscopic mechanical responses. Microstructural diversity in two-phase titanium alloys has triggered a profound platform in exploring this sort of micro-plasticity events. While numerous investigations have enriched the fundamentals of slip/twin transfer across grain boundaries, understanding of such responses at phase boundaries has not drawn abundant attention, particularly when α-mechanical twinning can be activated. By integrating in-situ EBSD/SEM testing, crystallographic calculations, and microstructure-based strain mapping approach, we aim to address the following three propositions: (1) could deformation transfer take place in the form between mechanical twinning in the α-phase and dislocation glide in the β-phase? (2) What parameters would be rational to quantify the propensity for the incipience of this event? (3) What micro-mechanical consequences are associated with the slip-twin transfer activity? Broader indications for mechanistically-guided microstructural design will also be discussed.
9:50 AM
Variability in Mechanical Properties Related to Porosity in LMD Waspaloy: Azdine Nait-Ali1; Romain Bordas1; Roland Fortunier1; Patrick Villechaise1; Lucie Rat2; Sebastien Rix2; Samuel Hemery1; Jonathan Cormier1; 1Isae Ensma; 2Safran Aircraft Engines
Laser Metal Deposition (LMD) is a promising technique for the repair of aero-engine components. Within this context, the influence of porosity on mechanical properties (tension, fatigue, creep) in LMDed Waspaloy has been investigated. Morphology and distribution analyzes were performed using 3D-images obtained by X-ray computed tomography. A complete statistical study using, e.g., covariogram allows us to highlight characteristic parameters such as characteristic distances, distribution probability law of inclusions, all these data being essential to link the mechanical response with LMD processing parameters. The questions addressed in this presentation are the effect of the spatial distribution, size distribution of pores on the local mechanical fields and resulting static/cyclic mechanical properties. We also want to understand how pores evolve during service life of LMDed repaired components. Simulations are made using a spectral solver (FFT) so that we can perform calculations on large volumes of data directly from the tomography and EBSD data.