Effect of Microstructure and Zr Addition on the Crystallographic Orientation Relationships among Phases related to the Eutectoid Decomposition of Nb_3Si in near Eutectic Nb-Si alloy

摘要

The authors have reported in the previous study that the sluggish decomposition of Nb_3Si phase is effectively accelerated by Zr addition. This is obvious at lower temperature range than the nose temperature of the TTT curve. In the present study a eutectic alloy containing 1.5 % of Zr was investigated. The Crystallographic orientation relationships among phases, such as eutectic Nb and product phases formed by eutectoid decomposition of Nb_3Si (eutectoid Nb and Nb_5Si_3 phases) in the Zr-containing sample which was heat treated at 1300℃ were investigated by FESEM/EBSD for further understanding of the decomposition process in alloy with a different microstructure.