Effect of Nb3Si Precipitates on the Deformation of the Primary Nb Phase in Nb-10a/o Si In-Situ Composite

摘要

The objective of this study is to determine the effect of the Nb3Si precipitateson the primary Nb phase, and find the mechanisms which limit high temperature deformation and subsequent recovery. It was observed that; Nb3Si precipitates in the Nb phase pin individual dislocations, dislocation subgrain boundaries and high angle grain boundaries. The volume fraction of Nb3Si precipitates varies from dendrite to dendrite in the primary Nb as a result of coring during solidification. The extent of recrystallization following deformation varies with the volume fraction of Nb3Si precipitates. This could account for the appearance of cleavage fracture in the metallic niobium phase in regions with high average silicon content.