Copper Concentration inside Guinier-Preston I Zones Formed in an Al–Cu Alloy

Abstract

The copper concentration inside a Guinier-Preston (GPI) zone was studied by means of an extended Hu Èckel molecular orbital (EHMO) calculation. The present EHMO calculation revealed that the Cu concentration inside a GPI zone depends on the size of the zone. The GPI zone comprises both Cu and Al in a small GPI zone, whereas the Cu concentration inside the GPI zone increases to nearly 100 at.% Cu in a large GPI zone. A compressive lattice distortion, which is associated with the zone, increases the stability, but when a GPI zone is 5 nm in diameter, the stabilizing effect of the zone is estimated to be not higher than 10 % of the chemical energy due to Cu coalescence.

Morphology and crystallographic phase of V–C particles formed in Fe–Cr–Ni–V–C alloys

“…Although the EHMO calculation is categorised into an empirical method, this sort of calculations has been successfully applied in various fields and provided useful information on the structures and properties also in alloys. [15][16][17][18][19][20][21][22] In analysing these calculations, we consider the following three parameters. The first is the cohesive energy, which gives a measure of the strength of the chemical bond.…”

A Quantitative Study of Precipitation of Metastable Phases in an Al-1.94 at%Cu Alloy during Isothermal Aging at 373 K

“…A possible interpretation may be drawn from the studies suggesting that the copper content inside the monolayer platelets is changed, depending on the size. [13][14][15] Unlike the HRTEM images, on the other hand, the HAADF-STEM image is formed by incoherent electron waves. HAADF-STEM imaging can distinguish solute clusters, G.P.…”