Ordering and structural vacancies in non-stoichiometric Cu–Al γ brasses

Kisi, Erich H.; Browne, J. D.

doi:10.1107/s0108768191005694

Cited by 45 publications

(23 citation statements)

References 13 publications

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“…The grain refinement and reduced nucleation undercooling of primary Cu6Sn5 due to Al additions has been deduced to be due to heterogeneous epitaxial nucleation of Cu6Sn5 on either -Cu33Al17 or 1-Cu9Al4 [7]. These two Al-Cu intermetallics have very similar crystal structure [7,9,10] and it was shown that both can form interfaces with only ~2.5% lattice mismatch to the first order and second order prism planes of Cu6Sn5 (i.e. the {11 ̅ 00} and {112 ̅ 0}-type planes of Cu6Sn5) [7].…”

Section: Introductionmentioning

confidence: 88%

Controlling Bulk Cu6Sn5 Nucleation in Sn0.7Cu/Cu Joints with Al Micro-alloying

Xian

Belyakov

Gourlay

2015

Journal of Elec Materi

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We show that dilute Al additions can control the size of primary Cu6Sn5 rods in Sn-0.7Cu/Cu ball grid array (BGA) joints. In Sn-0.7Cu-0.05Al/Cu joints, the number of primary Cu6Sn5 per mm 2 is ~7 times higher and the mean three dimensional (3D) length of rods is ~4 times smaller than in Al-free Sn-0.7Cu/Cu joints, while the area fraction of primary Cu6Sn5 is similar. It is shown that epitaxial nucleation of primary Cu6Sn5 occurs on δ-Cu33Al17 or γ1-Cu9Al4 particles, which are stable in the Sn-0.7Cu-0.05Al melt during holding at 250C. The observed facet relationships agree well with previously determined orientation relationships between δ-Cu33Al17 and Cu6Sn5 in hypereutectic Sn-Cu-Al alloys and result in a good lattice match with <~2.5% lattice mismatch on two different interfacial planes.2

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Section: Introductionmentioning

confidence: 88%

Controlling Bulk Cu6Sn5 Nucleation in Sn0.7Cu/Cu Joints with Al Micro-alloying

Xian

Belyakov

Gourlay

2015

Journal of Elec Materi

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“…As the last type of gamma-brasses, we have Al 8 Cr 5 36 and the Al-rich Cu-Al gamma-brasses. 37 When excess Al is added to Cu 9 Al 4 , vacancies are introduced mainly into the site IT and the derivative structure of a lower symmetry with fewer atoms per unit cell is formed. It is described as rhombohedral symmetry with α =89.8o of the space group 3 R m , a subgroup of 43 P m .…”

Section: Gamma-brasses As a Representative Of Structurally Complex Almentioning

confidence: 99%

The Hume-Rothery Rules for Structurally Complex Alloy Phases

Mizutani

2010

Book Series on Complex Metallic Alloys

110

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The underlying physics behind the Hume-Rothery rules, which have earned great reputations over the past century in the field of materials science in designing new alloys, is reviewed. The discussion is developed following several key themes: (a) what is the critical depth and width of the pseudo-gap to stabilize a complex metallic alloy?, (b) what does the Hume-Rothery stabilization mechanism mean?, (c) the existence of FsBz-induced and orbital hybridization-induced pseudo-gaps, (d) the need of distinguishing two different electron concentrations e/a and VEC, (e) are most quasicrystals really scaled in terms of e/a and stabilized via the FsBz-induced pseudo-gap mechanism? The answer is "no".

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“…The 2 -phase, slightly richer in Al, is proposed to be stable below 575 • C. A monoclinic [4] and a hexagonal lattice [5], and more recently, orthorhombic lattices [6,7] have been assigned to these phases. They coexist with a rhombohedrally distorted ␥-brass-related phase (␦) [8] and with AlCu [9] forming a unique superstructure of a metal-deficient Ni 2 In-type structure. Such a disordered Ni 2 In-type-related structure is proposed for ε 2 -Al 2+ δ Cu 3 [9].…”

Section: Introductionmentioning

confidence: 99%