Investigation on the Freeze Casting Porous Al_2O_3 Ceramic Bodies Infiltrated with Nb-Ti-Al-Cr Alloy by Pressureless Infiltration

摘要

This paper adopted freeze casting method to prepare porous Al_2O_3 ceramic bodies with different volume percentage and interconnected pore channels as the preform. The porous Al_2O_3 ceramic bodies were pressureless infiltrated with Nb-35Ti-20Al-10Cr alloy (atom percentage, at%) by using electromagnetic induction furnace. The results indicated that there is a well wettability between Nb-35Ti-20Al-10Cr melt and porous Al_2O_3 ceramic body. And it would be possible to infiltrate Nb-35Ti-20Al-10Cr melt into porous Al_2O_3 ceramic body through pressureless infiltration. The microstructure observation for the Nb-35Ti-20Al-10Cr/Al_2O_3 composites demonstrated that it was still retained the layer structure characteristics of the preform. The Nb-35Ti-20Al-10Cr melt was filled into the interconnected pore channels existed in the porous Al_2O_3 ceramic bodies and the Nb, Ti, Al, Cr alloy elements diffused into the reinforced Al_2O_3 particles during pressureless infiltration.