عنوان

Atomic-Scale Modeling of Twinning in Titanium and Other HCP Alloys

Number

TLpq2442816811

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Atomic-Scale Modeling of Twinning in Titanium and Other HCP Alloys

General Material Designation

[Thesis]

First Statement of Responsibility

Hooshmand, Mohammad Shahriar

Subsequent Statement of Responsibility

Ghazisaeidi , Maryam

Name of Publisher, Distributor, etc.

The Ohio State University

Date of Publication, Distribution, etc.

2019

Specific Material Designation and Extent of Item

167

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

The Ohio State University

Text preceding or following the note

2019

Text of Note

Titanium (Ti) and its alloys have a wide range of applications in biomedical, automotive and aerospace industries due to their excellent strength to weight ratio and corrosion resistance. Alpha phase Ti has hexagonal closed packed (hcp) structure that shows anisotropic plastic deformation; ⟨ a ⟩ type slip on prism planes is the easiest to activate but cannot accommodate deformation along the ⟨ c ⟩ axis. The low temperature ductility of Ti is linked to twinning. Therefore, understanding the mechanisms behind the twin nucleation and growth in Ti alloys is important from both theoretical and industrial application points of view. To that end, the present study seeks a better understanding of the atomic scale processes involved in twin nucleation mechanisms and the effect of alpha-stabilizing solutes such as interstitial oxygen, substitutional aluminum and rare earth elements on twinning. Systematic molecular dynamics (MD) simulations are used to identify the underlying mechanism of twin nucleation from dislocation/grain boundary interactions. Density functional theory (DFT) simulations are employed to examine the effect of oxygen interstitials on the twinning behavior of Ti. A systematic framework has been developed to predict the diffusion of interstitial elements near the twin boundaries in hcp alloys. Next, uncertainty that arises from first-principles calculations in predicting diffusion coefficients are quantified. Finally, solute segregation to the twin boundaries as a new mechanism for dynamic strain aging (DSA) is investigated in Ti and other hcp alloys.

Computer science

Materials science

Ghazisaeidi , Maryam

Hooshmand, Mohammad Shahriar

Electronic name

p

[Thesis]

276903

a

Y