Purveyors of Processing Science and ICME: A SMD Symposium to Honor the Many Contributions of Taylan Altan, Wei Tsu Wu, Soo-Ik Oh, and Lee Semiatin: Advances and Challenges in ICME
Sponsored by: TMS Structural Materials Division, TMS: Shaping and Forming Committee, TMS: Titanium Committee
Program Organizers: Adam Pilchak, Pratt & Whitney; Ayman Salem, MRL Materials Resources LLC; Viola Acoff, University of Mississippi; Nathan Levkulich, UES; Michael Glavicic, Rolls-Royce; Yufeng Zheng, University of North Texas; John Joyce-Rotella, Air Force Research Laboratory
Wednesday 2:00 PM
February 26, 2020
Room: 30E
Location: San Diego Convention Ctr
Session Chair: Viola Acoff, University of Alabama; Noah Phillips, ATI
2:00 PM Invited
Microstructure Underpins Processing: Anthony Rollett1; 1Carnegie Mellon University
Processing materials is often concerned with obtaining the best possible microstructure, provided that one can obtain the desired shape. Understanding how to achieve this has of course been a main objective of Lee Semiatin’s career. Many aspects must come together such as solidification, plasticity, dislocation structures, stored energy, anisotropy, recrystallization and grain growth. Processing science is therefore a demanding domain because of the thorough scientific knowledge to underpin the phenomenology. Heterogeneity in microstructure must be controlled, whether it be avoiding abnormal grain growth or mitigating the effects of large grains inherited through a phase transformation. 3D printing has reinvigorated metallurgy because it provides rapidly solidified metals in bulk form. Traditional analysis such as TTT diagrams are still useful but must be re-measured for the new processes. Several examples will be given of where understanding microstructural evolution is essential for processing.
2:30 PM Invited
The Challenges of Refractory Alloy Processing: A Case Study in a Refractory Complex Concentrated Alloy: Noah Philips1; 1ATI
The application of refractory materials has always depended on balancing exceptional properties at high temperatures with exceptional difficulty in processing. The commercial viability of any refractory material product thus often relies upon solving challenges in processing. There are additional material properties that, while not critical for the application, are sufficiently central to processing that they determine the feasibility of a product. In some cases, such as hot working operations, there is a fundamental incompatibility between the requirements of the process and that of the application. This talk will review such challenges in producing refractory materials at scale through the case study of a refractory complex concentrated alloy.
3:00 PM
Zoning Thermomechanical Process History Data Using Unsupervised Machine Learning: Sean Donegan1; Dennis Dimiduk2; Michael Groeber2; 1Air Force Research Laboratory; 2The Ohio State University
Understanding and quantifying process-structure relationships in thermomechanical processing through modeling and simulation is a foundational aspect of ICME. Such modern process models are capable of producing data streams having high dimensionality both in space and time; and, developing workflows that relate such complex data to resulting measured microstructure remains a challenge. We present a procedure for reducing the overall complexity of process model data by zoning: grouping together regions of a component having similar process histories. This zoning procedure utilizes unsupervised techniques from machine learning to develop this lower dimensional representation without expert intervention. We demonstrate this zoning procedure in two application areas: i) relating process output from a DEFORMŽ pancake forging simulation of a Ti-6242Si cylinder to measured microstructure; and ii) comparing process histories computed from a fast-acting thermal model of powder bed fusion additive manufacturing across different component geometries.
3:30 PM Invited
Modeling Pore Closure in Titanium Alloys: Michael Gram1; 1Titanium Metals Corporation, Henderson, NV
Porosity can form in Titanium alloys during both solidification and thermomechanical processing. Regardless of how it forms, if porosity is not closed during subsequent processing pores can serve as stress concentrators which reduce performance in service. In order to understand the requirements for pore closure, small scale rolling tests were carried out and compared to established mean field pore evolution models as well as discrete pore models using a representative volume element (RVE) approach. The mean field and RVE approaches were then applied to model full scale ingot conversion processes to predict pore size evolution using realistic macroscopic loading conditions and ultimately determine requirements for pore closure. Results show that given an assumed or measured initial pore size, aspect ratio, and orientation, modeling can be used to generate strategic forging routes capable of closing pores.
4:00 PM Invited
Development and Optimization of a Novel SPPARKS Recrystallization Model for AM IN718: Austin Gerlt1; David Newell2; Adam Pilchak3; Lee Semiatin3; Eric Payton3; 1UES, Inc.; 2Air Force Institute of Technology; 3Air Force Research Laboratory
This talk explores a newly developed Monte Carlo-based grain evolution code designed to model the annealing of structural metals. The code is an adaptation of the classical curvature-driven Potts model that includes both pinning particles and dislocation density as driving forces. The model parameters were than specifically tuned to emulate the annealing of additively manufactured Inconel 718 using several sets of experimental results as ground truth experiments. Furthermore, this model has been built within the popular open source SPPARKS framework, allowing for the quick adaption and implementation by anyone interested in replicating this functionality.
4:30 PM Concluding Comments