The Orientation and Shape of θ Precipitates Formed in an AlCu Alloy

Abstract

Abstract Several new orientation groups have been observed for θ precipitates in an Al‐4% Cu alloy. All orientations so far known for θ in relation to both θ′ and the aluminium matrix are summarised. There are 159 known possible orientations for a θ particle relative to the aluminium matrix. Details of the matching interfaces and some of the factors governing nucleation and growth of θ particles are discussed.