Deformation-induced Phase Transformations: Deformation-induced Phase Transformations
Program Organizers: Yangyang Zhao, Purdue University; Jonah Klemm-Toole, Colorado School of Mines; Amy Clarke, Los Alamos National Laboratory; Janelle Wharry, Purdue University
Monday 2:00 PM
October 18, 2021
Room: B132
Location: Greater Columbus Convention Center
2:00 PM Invited
Ausforming of Ferrium M54 Ultra-high Strength Steel: Suveen Mathaudhu1; Yiwei Sun2; Joshua Edwards1; Jeffrey Lin3; Thomas Kozmel3; 1Colorado School of Mines; 2Southeast University; 3Questek Innovations, LLC
Ferrium M54 is a medium-carbon ultra-high strength steel with potential for achieving outstanding strength, toughness and stress corrosion cracking resistance. A processing route involving ausforming and tempering was implemented to reveal the interconnections between processing, microstructure and mechanical properties. Roll reduction and temperature were varied parametrically, and their effects of refinement of the lath martensite explored. In turn, the effect of the hierarchical microstructures on the hardness and tension properties, but pre- and post-aging is also investigated. An empirical model was developed for prediction of the optimal processing window for M54. The combination of ausforming and aging is shown to be an excellent pathway to refine martensite, accelerate the aging response and increase the strength in Ferrium M54 and likely other high-strength steels.
2:40 PM
Analysis of Stress State of Plastic Medium Influence on Structural Transformations in Low-alloy Steels: Anton Matiukhin1; Sergey Sheyko2; Vоlоdimir Tsyganov1; Valeriy Naumyk1; Anna Ben1; 1“Zaporizhzhia Polytechnic” National University; 2Zaporizhzhia National University
A method for determination of the influence of the stress-strain state of metal on the structural transformations in the low-alloy steel 10HFBTCh is provided. The relation between the parameters of the stress state, thermo-mechanical processing and structural changes in the deformation zone is shown based on the solution of spatial problems of the plasticity theory, the experimental research of mechanical characteristics of the low-alloy steel, the structural state of the metal after deformation. Experimental and theoretical method can be used for the development of technological modes of rolling of the new steel grade with specified mechanical properties customized.
3:00 PM
Localized Phase Transformation at Stacking Faults and the Corresponding Alloy Design Strategy: Longsheng Feng1; Ashton Egan1; Timothy Smith2; Shakthipriya Baskar1; Michael Mills1; Maryam Ghazisaeidi1; Yunzhi Wang1; 1The Ohio State University; 2NASA Glenn Research Center
Recent experimental studies found localized phase transformations (LPTs) at stacking faults in several Ni-based superalloys that significantly enhances creep resistance. Yet the mechanisms underlying the LPTs, in particular, how alloy compositions impact such phenomena are still unclear, imposing challenges to utilize LPTs in alloy design. We present a thermodynamic analysis of the LPT phenomena and address some critical questions such as why LPT happens, why LPT is confined at the stacking faults and how it impacts the mechanical properties. Such a thermodynamic analysis allows us to develop new alloy design criteria for LPT-strengthening, which is used to develop a high-throughput computation framework using CAPHAD to find new superalloys with maximized LPT effect. This work is supported by NSF under the DMREF program.
3:20 PM Break
3:40 PM Invited
Intrinsic Coupling between Deformation Twinning and Phase Transformation in NiTi Shape Memory Alloys and Metastable Beta Ti-alloys: Yipeng Gao1; Qianglong Liang1; Yufeng Zheng1; Dong Wang2; Michael Mills1; Hamish Fraser1; Yunzhi Wang1; 1Ohio State University; 2Xian Jiao Tong University
In addition to conventional dislocation plasticity, mechanical twinning and structural phase transformations are another two important plasticity carriers. In this presentation, we employ a combination of phase-transition-graph (PTG) analysis and TEM characterization to study systematically the deformation modes arising from the interplay between mechanical twinning and phase transformation. Using NiTi shape memory alloy and metastable beta Ti-alloy as examples, we show that mechanical twinning and phase transformations are intrinsically coupled in the symmetry-breaking processes, which results in multiple interconnected transformation and deformation pathways and characteristic twinning modes. This study not only reveals the physical origin of unique twinning modes and extended core structures of twin boundaries (e.g., nested twins) observed in experiments, but also provides new insights into the linear super-elasticity of cold-rolled NiTi and enhanced plasticity of metastable beta Ti-alloys through coupled twinning and transformation pathway coupling.
4:20 PM
Solid Phase Plasticity Mechanisms in Metals and Rocks during Shear Deformation: Suveen Mathaudhu1; Arun Devaraj2; 1Colorado School of Mines / Pacific Northwest National Laboratory; 2Pacific Northwest National Laboratory
All around us, things are constantly plastically deforming, whether it be at nanoscale atomic level in metallic alloys to the km-scale during geological flow in the lithosphere. We will present cross-cutting theories on the nature of pressure and shear-driven structural evolution in metals and geological materials. Novel solid-phase material deformation methods and in-situ beamline studies will reveal metallic deformation pathways that will be directly compared to the current earth science literature on ductile deformation in rocks. The finding forecast the ability to use laboratory scale tools and simulant materials to extend our understanding of how the world has moved underneath us and how it may deform in other parts of the universe.
4:40 PM
Accounting for Phase Transformation in Plastic Anisotropy Modeling of SS316L: Elizabeth Mamros1; Jinjin Ha1; Yannis Korkolis2; Brad Kinsey1; 1University of New Hampshire; 2Ohio State University
Plasticity of SS316L was characterized by uniaxial and biaxial tension experiments, including the effect of phase transformation on material behavior. Normalized flow stresses and strain ratios were calculated with respect to plastic work to capture the evolutionary behavior. The results were used to calibrate non-quadratic anisotropic yield function (Yld2004-18p) parameters as a function of equivalent plastic strain. In-plane biaxial tension cruciform experiments were performed to validate the plastic anisotropy model. The model predicted the experiments reasonably well for proportional paths ranging from uniaxial to equibiaxial loading. The resulting martensitic transformation was measured via magnetic induction and validated by electron backscatter diffraction. Alterations to the material properties of austenitic stainless steels resulting from deformation-induced martensitic transformation is of interest for creating heterogeneous biomaterials. By controlling stress superposition, the microstructure can be tailored to the desired material properties for a specific application, e.g., trauma hardware, which has conflicting strength and weight requirements.