Directionally Solidified Ti-48Al-2Cr-2Nb Made by Power Down or Bridgeman Processing

摘要

The microstructural attributes of directionally solidified Ti-48Al-2Cr-2Nb (in at/100) produced by the Power Down and Bridgeman techniques at various cooling rates/growth rates are presented. Fully lamella α_2-Ti_3Al＋γ-TiAl microstructures with γ particles on grain boundaries are present in all conditions. The directionally solidified structure consists of discreet e regions of columnar grains either parallel or radial to the growth direction, as well as a region of equipped grains. The phase structure and lamella structure made by the two techniques are examined. Increasing the cooling rate or growth rate decreases the portion of columnar grains parallel to the growth direction and decreases the lamelar interface spacing.