Formation behavior and interfaces of TiB in-situ formed in CP Ti matrix

摘要

Formation behavior and characteristics of theinterface which were in-situ formed between TiB2 reactant powderand a-Ti matrix were investigated. Furthermore, the effect of a TiBgrowth on densification of Ti/TiB2 mixture was also examined.Mixed powders of TiB2 or B4C powder with CP Ti powders werecompacted and pre-sintered at 700℃ for 1 hr followed bysintering at 900, 1000, 1100, 1200, 1300℃ for 3hrs, respectively.In addition, another specimens were sintered at 1000℃ forvarious times in order to study the formation behavior of TiBreinforcement in-situ formed in the α-Ti matrix. TiB was formedthrough the different mechanisms - formation of fine TiB andformation of coarse TiB by Ostwald ripening or coalescence offine TiB. There was no crystallographic relationship between TiBand matrix. There were voids at the interface between TiBreinforcement and α-Ti matrix because of the preferential growthof TiB without any crystallographic relationship with α-Ti matrixand the surface energy between Ti matrix and TiB reinforcements,and so densification of Ti/TiB2 compacts was hindered by the coarse TiB growth.