Theory of the resistivity and Hall effect in alloys during Guinier-Preston zone formation

Abstract

The theory of the resistivity maximum, based on Bragg scattering of electrons from Guinier-Preston zones, is described and is used to construct semi-phenomenological formulae for the resistivity appropriate to various types of alloy configuration. When the parameters are determined from transport calculations the formulae will be useful in analysing the state of an alloy during ageing. It is shown, for example, that the size of cluster associated with peak resistivity varies with solute concentration and ageing temperature, but this is much less so for spherical zones than for flat zones. The theory is also able to reproduce the behaviour of the Hall coefficient in Al-Zn, which also peaks during ageing. It is argued that other zone-forming alloys may exhibit a maximum, a minimum or neither.