scholarly journals The Nucleation and the Intrinsic Microstructure Evolution of Martensite from 332113β Twin Boundary in β Titanium: First-Principles Calculations

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1202 ◽  
Author(s):  
Chen ◽  
Ma ◽  
Wang
Keyword(s):  
Twin Boundary ◽  
Microstructure Evolution ◽  
First Principles ◽  
Atomic Scale ◽  
Clear Understanding ◽  
Intermediate Structure ◽  
First Principles Calculations ◽  
Ti Alloys ◽  
Α Phase ◽  
Strength And Ductility

A clear understanding on the inter-evolution behaviors between 332113β twinning and stress-induced martensite (SIM) α″ in β-Ti alloys is vital for improving its strength and ductility concurrently. As the preliminary step to better understand these complex behaviors, the nucleation and the intrinsic microstructure evolution of martensite α″ from 332113β twin boundary (TB) were investigated in pure β-Ti at atomic scale using first-principles calculations in this work. We found the α″ precipitation prefers to nucleate and grow at 332113β TB, with the transformation of 332113β TB→130310α” TB. During this process, α″ precipitation firstly nucleates at 332113β TB and, subsequently, it grows inwards toward the grain interiors. This easy transition may stem from the strong crystallographic correspondence between 332113β and 130310α” TBs, and the region close to the 332113β TB presents the characteristics of intermediate structure between β and α″ phases. Kinetics calculations indicate the α″ phase barrierlessly nucleates at 332113β TB rather than in grain interior, where there is higher critical driving energy. Our calculations provide a unique perspective on the “intrinsic” microstructure evolution of martensite α″ from 332113β TB, which may deepen our understanding on the precipitation of martensite α″ and the inter-evolution behaviors between 332113β twinning and martensite α″ in β-Ti alloys at atomic scale.

Stability of α Phase in Ti Alloys Containing Al or Zr from First-Principles Calculations

2013 ◽  
Vol 634-638 ◽  
pp. 1831-1835
Author(s):  
Zhong Bo Zhou ◽  
Hong Chao Kou ◽  
Xiang Yi Xue ◽  
Hui Chang ◽  
Li Jun Zhang ◽  
...  
Keyword(s):  
First Principles ◽  
Plane Waves ◽  
Repulsive Interaction ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Al Content ◽  
Generalized Gradient Approximation ◽  
Ti Alloys ◽  
Α Phase ◽  
The Stability

The energetic and electronic structure of α-type Ti1-xXx (X=Al and Zr, x=0.0625, 0.125, 0.185, 0.250, 0.3125and 0.375) binary alloys were calculated by the method of supercell and augmented plane waves plus local orbitals within generalized gradient approximation. The results show that the formation energy decreases with the composition of Al, while increases with composition of Zr, which indicate that α phase can be enhanced by increasing the Al contents while weaken by increasing Zr contents. The DOS results shows that the Fermi levels of Ti1-x Al x and Ti 1-x Zr x fall on a dip of a DOS curve, which means the α structure of these alloys is stable. When the Al content is increased, the charge transfer between the Al and its neighbors becomes more evident, and enhance the stability of the α phase. With an increase of Zr content, repulsive interaction between two Ti atoms strengthen, which result in the α phase stability decrease.

First-principles calculations for development of low elastic modulus Ti alloys

2004 ◽  
Vol 70 (17) ◽  
Author(s):  
Hideaki Ikehata ◽  
Naoyuki Nagasako ◽  
Tadahiko Furuta ◽  
Atsuo Fukumoto ◽  
Kazutoshi Miwa ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
First Principles ◽  
First Principles Calculations ◽  
Ti Alloys ◽  
Low Elastic Modulus

scholarly journals Preferential proton conduction along a three-dimensional dopant network in yttrium-doped barium zirconate: a first-principles study

2018 ◽  
Vol 6 (45) ◽  
pp. 22721-22730 ◽  
Author(s):  
Kazuaki Toyoura ◽  
Weijie Meng ◽  
Donglin Han ◽  
Tetsuya Uda
Keyword(s):  
First Principles ◽  
Three Dimensional ◽  
Proton Conduction ◽  
Atomic Scale ◽  
Barium Zirconate ◽  
First Principles Calculations ◽  
First Principles Study

The atomic-scale picture of proton conduction in highly doped barium zirconate has theoretically been clarified using first-principles calculations.

Phase stability and elastic modulus of Ti alloys containing Nb, Zr, and/or Sn from first-principles calculations

2008 ◽  
Vol 93 (12) ◽  
pp. 121902 ◽  
Author(s):  
Qing-Miao Hu ◽  
Shu-Jun Li ◽  
Yu-Lin Hao ◽  
Rui Yang ◽  
Börje Johansson ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Phase Stability ◽  
First Principles ◽  
First Principles Calculations ◽  
Ti Alloys

Characterisation of the temperature-dependent M1 to R phase transition in W-doped VO2 nanorod aggregates by Rietveld refinement and theoretical modelling

2020 ◽  
Vol 22 (15) ◽  
pp. 7984-7994
Author(s):  
Lei Miao ◽  
Ying Peng ◽  
Dianhui Wang ◽  
Jihui Liang ◽  
Chaohao Hu ◽  
...  
Keyword(s):  
Rietveld Refinement ◽  
First Principles ◽  
Atomic Scale ◽  
Theoretical Modelling ◽  
First Principles Calculations ◽  
Temperature Dependent ◽  
Macro Scale ◽  
Scale Properties ◽  
W Doping ◽  
Synchrotron Xrd

Synchrotron XRD Rietveld refinement is combined with first-principles calculations to probe the effect of W doping on the IMT mechanism in VO2 nanorods, providing insights into the connection between atomic-scale phenomena and macro-scale properties.

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