- Title Information
- Title
- First-Principles Calculations of Alloy Free Energies
- Type of Resource (primo)
- dissertations
- Name:
Personal
- Name Part
- Samanta, Sayan
- Role
- Role Term:
Text
- creator
- Name:
Personal
- Name Part
- van de Walle, Axel
- Role
- Role Term:
Text
- Advisor
- Name:
Personal
- Name Part
- Qi, Yue
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Peterson, Andrew
- Role
- Role Term:
Text
- Reader
- Name:
Corporate
- Name Part
- Brown University. School of Engineering
- Role
- Role Term:
Text
- sponsor
- Origin Information
- Copyright Date
- 2022
- Physical Description
- Extent
- 12, 80 p.
- digitalOrigin
- born digital
- Note:
thesis
- Thesis (Ph. D.)--Brown University, 2022
- Genre (aat)
- theses
- Abstract
- High-throughput computational thermodynamic approaches are becoming an increasingly popular tool to uncover novel compounds. However, traditional methods tend to be limited to stability predictions of stoichiometric phases at absolute zero. Such methods thus carry the risk of identifying an excess of possible phases that do not survive to temperatures of practical relevance. We demonstrate how the CALPHAD formalism, informed by simple first-principles input can be used to overcome this problem at a low computational cost and deliver quantitatively useful phase diagram predictions at all temperatures. We illustrate the method by re-assessing prior compound formation predictions and reconcile these findings with long-standing experimental evidence to the contrary.
Coupled with the Special Quasirandom Structure (SQS) formalism, CALPHAD offers a natural and efficient tool to generate input data for disordered solid solution phases. However, accounting for short range order (SRO) effects in a computationally efficient way presents a challenge. In this work we augmented the aforementioned computational toolkit to utilize the Cluster Variation Method (CVM) method in tandem with the SQS formalism. Our approach, implements the CVM to any level of accuracy, and determines a closed-form nonlinear expressions for temperature-dependent SRO corrections to the formation free energies. As a proof of concept, we re-assess the Ir-Ru binary alloy with SRO correction and show that under the tetrahedron approximation, the SRO correction to the hcp phase is sufficient to accurately reproduce the known experimental phase diagram.
Beyond equilibrium phase properties, the gamut of material properties of interest in engineering applications, extend to kinetically stabilized phases such as in Bulk Metallic Glasses (BMG). However experimental assessment of liquid properties is a time and economic bottleneck. To address this, we develop an Embedded Atom Method (EAM) force-field for the family of Zr-Cu-Al-Ni from a set of first principle calculations as reference data. The EAM was validated using an independent test data-set. Molecular Dynamics simulations to calculate equilibrium volume and viscosity at different liquid temperatures stipulate a good agreement with known experimental trends. Our developed EAM would thus be instrumental in accelerating screening of candidate BMG alloys of the Zr-Cu-Al-Ni family in a high-throughput pipeline.
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01149832")
- Topic
- Thermodynamics
- Subject
- Topic
- Computational modeling
- Subject
- Topic
- CALPHAD
- Subject
- Topic
- Cluster Variation Method
- Subject
- Topic
- Embedded Atom Method
- Subject
- Topic
- Short Range Order
- Subject
- Topic
- Electronic Structure Calculation
- Language
- Language Term (ISO639-2B)
- English
- Record Information
- Record Content Source (marcorg)
- RPB
- Record Creation Date
(encoding="iso8601")
- 20221018