Domain growth and off-phase boundary structures in L12-type ordering

Oguma, Ryuichiro; Eguchi, Tetsuo; Matsumura, Shuichi; Son, S. K.

doi:10.1016/j.actamat.2005.11.021

Cited by 12 publications

(7 citation statements)

References 12 publications

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“…8(b)), the boundary plane lies planes D and A. Consequently, every S ary has 12 Cu atoms as the nearest neig the same as that of the perfect D019 latt tion, for APBs of type 2 (Fig. 8(c)), the between the (01 1 0) planes A and B, thus boundary has two Sn atoms and ten Cu On the basis of the analogy between g and an elastic energy [7], the condition for isotropic media is obtained as follows;…”

Section: Resultsmentioning

confidence: 97%

“…We derived a TDGL formulation for D0 19 type ordering in the way similar to the case of L1 2 [7]. The order parameters are well defined, and mappings obtained from simulations of TDGL equations can be compared with dark-field TEM images.…”

Section: Discussionmentioning

confidence: 99%

“…It follows that the values of interface energy densities are lower than those of type 2. We recently developed theoretical treatment for L1 2 structure based on fcc structure [7]. Four nearest neighbor atoms in fcc form tips of regular tetrahedron as in the case of hcp.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetics of Ordered Domain Formation in Binary Alloys of D0<sub>19</sub> Type Order

Oguma

Matsumura

2015

Trans. Mat. Res. Soc. Japan

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The present authors have developed a Time-dependent Ginzburg-Landau (TDGL) model for microstructural evolution of D0 19 type ordering, taking into account the crystal symmetry of the ordered phase. The D0 19 structure based on hcp is divided into four equivalent sublattices. The site occupation probabilities are given as a function of three order parameters and a composition parameter. Multiple types of variants of the structures are represented by the order parameters. Mean-field free energies are defined in a form of Landau type expansion with the order parameters and the composition parameter. Interfacial energies due to local variations of degrees of order and composition are given in a gradient square approximation. Kinetic equations for time-evolution of the order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of the mean-field free energies and the interfacial energy terms. We distinguish characteristic off-phase boundaries observed in Transmission Electron Microscopy (TEM) images in such as Cu 3 Sn and Ti 3 Al, and performed three-dimensional numerical simulations based on the kinetic equations.

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Section: Resultsmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics of Ordered Domain Formation in Binary Alloys of D0<sub>19</sub> Type Order

Oguma

Matsumura

2015

Trans. Mat. Res. Soc. Japan

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“…To favor the mobility of the implanted nitrogen atoms and repair possible damage to the surface, we follow the sputtering by an annealing process, leading to the formation of a c(2x2)N reconstruction on the Cu 3 Au(100) surface, similar to that reported for Cu(100) [2]. A Cu 3 Au crystal can be in two distinct phases: an ordered L1 2 phase [16,17] upon annealing below a critical temperature T c = 663 K [18,19,20], and a disordered phase above this temperature [21,22]. While both phases have the FCC crystal structure, in the L1 2 phase the Au atoms are periodically distributed over the crystal whereas in the disordered phase they are not.…”

Section: Methodsmentioning

confidence: 94%

Large insulating nitride islands on Cu3Au as a template for atomic spin structures

et al. 2019

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We present controlled growth of c(2×2)N islands on the (100) surface of Cu 3 Au, which can be used as an insulating surface template for manipulation of magnetic adatoms. Compared to the commonly used Cu(100)/c(2×2)N surface, where island sizes do not exceed several nanometers due to strain limitation, the current system provides better lattice matching between metal and adsorption layer, allowing larger unstrained islands to be formed. We show that we can achieve island sizes ranging from tens to hundreds of nanometers, increasing the potential building area by a factor 10 3 . Initial manipulation attempts show no observable difference in adatom behaviour, either in manipulation or spectroscopy.

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“…Since its observation on 1934 2) in Cu-Zn alloys (brass), this transition which is expressed by the existence of one state in which atoms are ordered in crystal lattice, has been widely studied. [3][4][5][6][7] On the basis of X-ray diffraction, it has been noticed that below certain transition temperature, the atoms can be ordered on two sublattices which interpenetrate, i.e. the atoms of every type have tendency to take specific places in the crystal lattice by changing their position.…”

Section: Introductionmentioning

confidence: 99%

The Possibility of New Ordering Reaction in Cu-50 mass% Au Alloy

et al. 2011

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Among the large number of superlattices, there is a special group which may be classified as long period superlattices, the copper-gold system provides a classical example of such structure. Despite that historically, the copper-gold alloys containing about 25 atom percent gold were among the first investigated alloys, it still represents a subject of numerous studies. In the present work, we study all the possible phase transitions in the binary intermetallic alloy Cu 3 Au using differential scanning calorimetry (DSC) and differential dilatometry. A new important anomaly due certainly to a new ordered reaction has been detected at low temperature range by these two methods. To confirm this new reaction, we have used other techniques as high resolution transmission electron microscopy (HRTEM), electrical resistivity and microhardness measurements. The kinetics parameters as activation energy E act and Avrami exponent n have also been calculated respectively by Starink and John Mehl Avrami Kolmogorov (JMAK) methods.

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Domain growth and off-phase boundary structures in L12-type ordering

Cited by 12 publications

References 12 publications

Kinetics of Ordered Domain Formation in Binary Alloys of D0<sub>19</sub> Type Order

Kinetics of Ordered Domain Formation in Binary Alloys of D0<sub>19</sub> Type Order

Large insulating nitride islands on Cu3Au as a template for atomic spin structures

The Possibility of New Ordering Reaction in Cu-50 mass% Au Alloy

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