<i>In situ</i>TEM observations of the order-disorder transition at interfaces in Cu<sub>3</sub>Au

Tichelaar, F.D.; Schapink, F.W.; Li, Xiaofeng

doi:10.1080/01418619208205597

Cited by 20 publications

(8 citation statements)

References 22 publications

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“…This suggests that, in general, compositional disordering could be favored at grain boundaries. Such phenomenon has, indeed, been observed in TEM studies of antiphase boundaries and E3 coherent twin boundaries in Cu3Au [70,71]. It was observed that even in these interfaces which deviate only slightly from the perfect L12 structure, compositional disordering starts at temperature appreciably lower than the order-disorder transition temperature of the bulk.…”

Section: Discussionmentioning

confidence: 84%

Atomistic studies of the structure and composition of grain boundaries in Cu3Au and Ni3Al

Yan

Vítek

1995

Interface Sci

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Abstract. In this paper we investigate the atomic structure and composition of grain boundaries in Cu3Au (weakly ordered compound) and Ni3AI (strongly ordered compound). Computer simulations employing both the molecular statics and Monte Carlo methods were performed and the Finnis-Sinclair type many-body central force potentials used. First, grain boundaries in stoiehiometric alloys are studied with the goal to investigate the impact of ordering strength on the grain boundary structure and composition. In Cu3Au grain boundaries may become compositionally disordered even at room temperature and the compositional disordering is associated with segregation of gold. In contrast, in Ni3A1 grain boundaries remain compositionally ordered up to very high temperatures. Secondly, the structures of grain boundaries and the effect of Ni and AI segregation in non-stoichiometric Ni3A1 are investigated. Nickel segregation leads to compositional disordering at grain boundaries, while aluminum segregation, which is strongly selective, leads to an ordered grain boundary structure with high AI content. The possible relationship between structural and compositional characteristics of grain boundaries and their mechanical properties, in particular the grain boundary brittleness and its alleviation by additional alloying, are then discussed in the light of the results of this study.

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Section: Discussionmentioning

confidence: 84%

Atomistic studies of the structure and composition of grain boundaries in Cu3Au and Ni3Al

Yan

Vítek

1995

Interface Sci

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“…The first-order character of the transition implies the existence of hysteresis effects due to the barrier for the nucleation of the new phase. Detailed experimental evidence for such effects has been recently provided by transmission electron microscopy observations [6][7][8][9]. Detailed experimental evidence for such effects has been recently provided by transmission electron microscopy observations [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…Detailed experimental evidence for such effects has been recently provided by transmission electron microscopy observations [6][7][8][9]. Furthermore, in the case of twin boundaries, it has been shown that the extension of the temperature domain over which the disordered phase wets the interface depends on the atomic structure of the twin, i.e., symmetrical or asymmetrical [7]. Furthermore, in the case of twin boundaries, it has been shown that the extension of the temperature domain over which the disordered phase wets the interface depends on the atomic structure of the twin, i.e., symmetrical or asymmetrical [7].…”

Section: Introductionmentioning

confidence: 99%

Thermal disordering near a ?=3{111} twin boundary in Cu3Au

1994

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Symmetrical and asymmetrical configurations of a 2? = 3 (111) twin boundary in Cu3Au are studied by means of energy minimization and Monte Carlo simulations of a rigid lattice, using an adapted n-body potential. We find that relaxation occurring in the neighborhood of the boundary is larger for asymmetrical than for the symmetrical minimum energy configurations. From energy minimization the latter are also shown to correspond to the lowest excess energy. For the asymmetrical twin structure, Monte Carlo calculations of the long-range order parameter on a local basis show the existence of prewetting effects, i.e., the appearance well below the critical temperature of several partially disordered layers at each side of the twin boundary. In contrast, the order is preserved in the symmetrical twin in the same temperature range. These results are consistent with experimental observations of wetting in 2? = 3 (111) twins in Cu3Au, and it is found to occur at lower temperature in asymmetrical than in symmetrical boundaries.

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“…There are many interesting phenomena that can occur at boundaries, like segregation [6], wetting by the liquid or a different phase [7,8] etc. Recent observations have produced evidence for the wetting of boundaries in Cu3Au near the order-disorder transition by the disordered phase [9][10][11]. Cu3Au has the same structure as many technologically interesting intermetallics, and a relatively high order-disorder transition temperature, which makes the observation of the different facets of the ordering effects easy.…”

Section: Introductionmentioning

confidence: 99%

[001] Twist boundaries in Cu3Au for T ? 0 K

Polatoglou

1994

Interface Sci

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Four different [001] twist boundaries in Cu3Au spanning a wide range of the rotation angle are investigated for temperatures below the bulk order-disorder transition temperature. All the boundaries show almost identical behavior for the plane averaged stoichiometry and the order parameter at a given temperature. Within the accuracy of the calculations no segregation of either Cu or Au is observed to the boundary. At the boundary and below the transition temperature there is a layer which is more disordered than the rest of the crystal, and its width increases as the bulk order-disorder transition temperature is approached. This indicates wetting phenomena, which are in agreement with the experimental and theoretical results on other boundaries.

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In situTEM observations of the order-disorder transition at interfaces in Cu₃Au

Cited by 20 publications

References 22 publications

Atomistic studies of the structure and composition of grain boundaries in Cu3Au and Ni3Al

Atomistic studies of the structure and composition of grain boundaries in Cu3Au and Ni3Al

Thermal disordering near a ?=3{111} twin boundary in Cu3Au

[001] Twist boundaries in Cu3Au for T ? 0 K

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In situTEM observations of the order-disorder transition at interfaces in Cu3Au

Cited by 20 publications

References 22 publications

Atomistic studies of the structure and composition of grain boundaries in Cu3Au and Ni3Al

Atomistic studies of the structure and composition of grain boundaries in Cu3Au and Ni3Al

Thermal disordering near a ?=3{111} twin boundary in Cu3Au

[001] Twist boundaries in Cu3Au for T ? 0 K

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Product

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In situTEM observations of the order-disorder transition at interfaces in Cu₃Au