Effect of boundary on the alpha phase precipitation in a near-alpha titanium alloy

Abstract

Effect of boundary (β/β and α/β boundary) on the α phase precipitation in a near-α titanium alloy had been statistically investigated. The result shows that most grain boundary α (GBα) precipitates maintain a Burgers orientation relationship (BOR) with one of adjacent prior β grains. However, in some unique cases, the GBα did not maintain a BOR with either prior β grains due to preferential growth of equiaxed primary α (αp). It was also observed that the low-angle β/β boundaries can be passed through by secondary α (αs). Additionally, when an αp grain and an adjacent β grain have a near BOR, the preferred αs may form at αp/β boundary with the similar orientation to the αp due to low interfacial energy of low-angle αp/αs boundary.