Back to Search
Start Over
First-principles investigations ofωvariant selection during athermalβ→ωtransformation of binary Ti-xMo alloy
- Source :
- Computational Materials Science. 155:524-533
- Publication Year :
- 2018
- Publisher :
- Elsevier BV, 2018.
-
Abstract
- Variant selection during solid–solid phase transformation in titanium alloys affects greatly the microstructure and mechanical properties of the alloys. Theoretical investigations of the variant selection were generally performed by using phase field simulation that considers solely the elastic coherency strain energy. In the present work, we develop a model to determine the variant selection directly from first-principles calculations. The source of the variant selection is considered to be the varying free energy gains (including both bulk and interface contributions) induced by the transformation from the parent phase to different variants of the product phase. This model is applied to investigate the effects of shear stress and alloy composition on ω variant selection during athermal β → ω transformation in binary Ti-xMo ( x ≤ 25 at.%) alloys. The random distribution of the atoms in the alloy is described by using virtual crystal approximation (VCA). We show that the tendency of variant selection becomes stronger with increasing shear stress. With increasing Mo concentration, the favorable ω variant transfers from one to another, except for the ω phase with very small particle size (e.g., radius R ≤ 1 nm) where one variant is always selected. The critical Mo concentration for the transfer of the favorable ω variant approaches to 5 at.% with increasing size of the ω phase particles and remains almost unchanged against the shear stress. At the critical Mo concentration, the considered variants have equal free energy gains and there is no variant selection. This finding opens the possibility of controlling the variant selection and the associated microstructure by changing the composition of the alloys.
- Subjects :
- Work (thermodynamics)
Materials science
General Computer Science
Alloy
General Physics and Astronomy
Titanium alloy
Thermodynamics
02 engineering and technology
General Chemistry
Radius
engineering.material
021001 nanoscience & nanotechnology
Microstructure
01 natural sciences
Crystal
Computational Mathematics
Mechanics of Materials
Phase (matter)
0103 physical sciences
Shear stress
engineering
General Materials Science
010306 general physics
0210 nano-technology
Subjects
Details
- ISSN :
- 09270256
- Volume :
- 155
- Database :
- OpenAIRE
- Journal :
- Computational Materials Science
- Accession number :
- edsair.doi...........c515197818de827693cff4f19187380e