Strain-induced structural phase transition of a Ni lattice through dissolving Ta solute atoms

Abstract

The structural phase transition of a single-crystal Ni lattice upon dissolving Ta solute atoms is investigated by means of molecular-dynamics simulations with a realistic n-body Ni-Ta potential. It is found that when the solute concentration is within 9-19 at. % of Ta, the accumulated strain results in a martensitic phase transition, i.e., face-centered-cubic ͑fcc͒ Ni transforms into a face-centered-orthorhombic-͑fco͒ like structure through shearing, and that when the solute concentration is over 21 at. % of Ta, the Ni lattice collapses and turns into an amorphous state. Comparatively, for the case of an initial hcp Ni lattice, the same martensitic and amorphization transitions also take place. The former hcp-fco transition, however, is mainly through atomic rearrangement as well as readjustment of lattice parameters, and the resultant state is almost perfect single crystal with no shearing bands. Besides, the above structural transitions are frequently in association with a dramatic softening in shear elastic moduli.

Mechanical properties of Au nanowires under uniaxial tension with high strain-rate by molecular dynamics

“…Consequently, the cross section of [011] NWs in the x y-plane becomes elliptic instead of circular shape, while the [001] and [111] NWs still retain the shape of a circle. The results also 1.0286E+01 8.5714E+00 6.8571E+00 5.1429E+00 3.4286E+00 1.7143E+00 0.0000E+00 -1.7143E+00 -3.4286E+00 -5.1429E+00 -6.8571E+00 -8.5714E+00 show that the structures are transformed from FCC to facecentred-orthorhombic (FCO) like structures first and finally transformed to an amorphous state [32]. Since the system does not have enough time to form a compact microstructure at high strain-rate, some defects of voids appear during the deformation, as shown in figures 5(h) and (i).…”

Enhancing the stability of the ω phase of zirconium alloys via local interlayer twists

“…We investigate the interaction between LITs by monitoring the potential energy change of the Zr-Nb system as function of the distance between LITs by building a supercell with size 11×11×11 of perfect ω unit cells, two of which are replaced by LIT unit cells. The potential energy as a function of the LIT-LIT distance along three different directions (i.e., [11][12][13][14][15][16][17][18][19][20]ω a axis, [-1100]ω b axis, and [0001]ω c axis) is monitored 50 times and the results averaged. As shown in Fig.…”

“…On the one hand, dopants can influence the nucleation barrier of the product phase, which governs the incubation time and starting transition temperatures or pressures of the new phase [11,12]. On the other, solute atoms can induce local lattice distortion or change the local chemical environment, thus altering the growth process in new phases [13][14][15][16].…”

Structural Phase Transformation in Ni–Hf and Ni–Ti Systems Studied by Molecular Dynamics Simulation

“…% Ta. 8) Since the newly observed martensitic phase transformation possesses a common feature, which is seldom observed in typical phase transformations, i.e., they all evolve in a supersaturated solid solution, yet involving neither temperature variation nor stress induction, we propose to name such a type of phase transformation as a chemically mediated martensitic phase transformation. To obtain more insight into and hence to understand better this type of martensitic phase transformation on an atomic scale, the lattice dynamics calculation, the first-principles calculation and molecular dynamics (MD) and Monte Carlo simulations have successively been employed to model the detailed mechanism of the phase transformation.…”