Interfacial reaction

interfacial microstructure

element distribution and phase constituent of Ti-47Al-2Cr-2Nb alloy melt with Y2O3 shell mold were investigated in condition of different heating temperature and holding time combining with directional solidification technology.Feasibility of Y2O3 shell mold for directional solidification TiAl alloy parts was approached.The results show that

at a given holding temperature or holding time

Al element in the melt is more easily diffused into the mold shell side than Ti element.Meanwhile

infiltrated layer with 40～70μm in thickness can be formed on surface of the alloy rod.Formation of infiltrated layer at 1600 ℃ is attributed to the introduction of Y2O3 particle into the matrix alloy as a result of erosion and thermal impaction of liquid alloy to face materials of shell mold

while it is the result of reaction of Y2O3 with liquid alloy at 1700 ℃ because of the occurrence of grey phase containing Y

O

Al around Y2O3 particle.