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Computer-Aided Alloy Design and Microstructure Engineering

Sriram, Hariharan
http://rave.ohiolink.edu/etdc/view?acc_num=osu1704242110453732

Abstract Details

2024, Doctor of Philosophy, Ohio State University, Materials Science and Engineering.
Recent advancements in high-performance computing and CALPHAD databases have made it possible to develop and use computational tools to drive alloy design. Additionally, these tools have been successfully leveraged in building structure-property relationships, which are subsequently used to optimize the microstructure by tweaking alloy chemistry and processing routes to achieve the required properties. This work uses computational models such as the phase field framework, CALPHAD-based tools, and dislocation density-based constitutive models to understand phase transformation pathways and predict material properties in structural and functional multi-phase alloy systems. Three case studies are presented with different material systems where the frameworks mentioned above are used to perform alloy design and microstructure engineering. In the first case study, the phase field framework is coupled with the classical nucleation theory to explain the formation of several coprecipitate configurations in Inconel 718-type alloys. Insights gained from this study and CompuTherm’s PanPrecipitation module are used to optimize heat treatments to obtain a novel microstructure with bimodal coprecipitate distribution with superior creep properties relative to Inconel 718. The second case study discusses a novel approach to tame martensitic transformation in NiTi shape memory alloys (SMA). The approach involves engineering concentration modulation (CM) in the parent austenite phase through the dissolution of Ni_4 Ti_3 nanoprecipitates observed in Ni-rich NiTi SMAs to form a complex interpenetrating architecture of CMs with continuous variations in martensitic start temperatures. Phase field simulations are coupled with thermodynamic databases for the design of NiTi system with nanoscale CMs in the parent phase and their ability to linearize the stress-strain response are explored. The influence of elastic confinements from amorphous phase in crystal + amorphous nanocomposites with different microstructure configurations on taming martensitic transformation is also investigated. The third case study introduces a dislocation density-based microstructure-sensitive creep model to predict the creep curves of cast aluminum alloys for varying temperature and stress levels. The model is benchmarked against experimental creep data.
Yunzhi Wang, Dr. (Advisor)
Michael Mills, Dr. (Committee Member)
Steve Niezgoda, Dr. (Committee Member)
148 p.
Materials Science

Recommended Citations

Citations

  • Sriram, H. (2024). Computer-Aided Alloy Design and Microstructure Engineering [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1704242110453732

    APA Style (7th edition)

  • Sriram, Hariharan. Computer-Aided Alloy Design and Microstructure Engineering . 2024. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1704242110453732.

    MLA Style (8th edition)

  • Sriram, Hariharan. "Computer-Aided Alloy Design and Microstructure Engineering ." Doctoral dissertation, Ohio State University, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=osu1704242110453732

    Chicago Manual of Style (17th edition)

osu1704242110453732
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This open access ETD is published by The Ohio State University and OhioLINK.
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