Effects of alloying elements on the cohesion of {101¯1} twin boundary from first-principles calculations

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.

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[P6] Effects of alloying elements on elastic properties of Al by first-principles calculations

Calphad ◽

10.1016/j.calphad.2015.01.095 ◽

2015 ◽

Vol 51 ◽

pp. 372-373

Author(s):

Jiong Wang ◽

Yong Du ◽

Shun-Li Shang ◽

Zi-Kui Liu ◽

Yiwei Li

Keyword(s):

Elastic Properties ◽

First Principles ◽

Alloying Elements ◽

First Principles Calculations

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Effect of Alloying Elements on the Elastic Properties of γ-Ni and γ'-Ni3Al from First-principles Calculations

MRS Proceedings ◽

10.1557/proc-1224-ff05-31 ◽

2009 ◽

Vol 1224 ◽

Cited By ~ 8

Author(s):

Yunjiang Wang ◽

Chongyu Wang

Keyword(s):

Elastic Properties ◽

First Principles ◽

Electronic Structures ◽

Elastic Moduli ◽

Lattice Misfit ◽

Alloying Elements ◽

First Principles Calculations ◽

Strengthening Mechanisms ◽

Two Phases ◽

Effect Of Alloying

AbstractThe effect of alloying elements Ta, Mo, W, Cr, Re, Ru, Co, and Ir on the elastic properties of both γ-Ni and γ′-Ni3Al is studied by first-principles method. Results for lattice properties, elastic moduli and the ductile/brittle behaviors are all presented. Our calculated values agree well with the existing experimental observations. Results show all the additions decrease the lattice misfit between and γ′ phases. Different alloying elements are found to have different effect on the elastic moduli of γ-Ni. Whereas all the alloying elements slightly increase the moduli of γ′-Ni3Al expect Co. Both of the two phases are becoming more brittle with alloying elements, but Co is excepted. The electronic structures of γ′ phase alloyed with different elements are provided as example to elucidate the different strengthening mechanisms.

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