Effects of Ternary Additions on the Microstructure of Directionally-Solidified MoSi_2/Mo_5Si_3 Eutectic Composites

摘要

Microstructural variations of directionally-solidified (DS) MoSi_2/Mo_5Si_3 eutectic composites caused by ternary additions of V, Cr, Nb, Ta and W were investigated. Ternary addition of relatively large amount of V resulted in the apparent modification of the morphology as well as the macroscopic inclination angle of one type of the interfaces extending nearly along the growth direction in the DS ingots. Ternary addition of Cr was found to change the microstructures of the DS ingots from a cellular-type with coarse boundary regions to a plate-like cellular-type with increasing the amount of the ternary addition. No significant change of script-lamellar morphology was observed for the DS ingots containing Nb, Ta and W irrespective of the amount of the ternary addition.