Activation Mechanism and Infiltration Kinetic for Pressureless Melt Infiltration of Ti Activated Al2O3 Preforms by High Melting Alloy

Activation mechanism and infiltration kinetic for pressureless melt infiltration of Ti activated Al 2O 3 preforms by high melting alloy, was reported. Porous alumina preforms were prepared with fine and coarse alumina powders mixed with different amounts of either fine or coarse titanium activator. Pressed pellets of powder mixtures A100T40-i and A20T40-i with i = 1, 3, 5, 10, and 20wt% of titanium activator and A100T200-i and A20T200-i with i = 3, 5, and 2Owt% Ti were fabricated. Average pore diameter and porosity of the powder compacts were analyzed by mercury intrusion porosimetry, helium pycnometry, and mercury buoyancy methods. The 3D microstructure, the spatial distribution of the titanium particle, and the inter-particle distances were obtained from X-ray tomography measurements. SEM and EDS measurement of the Ti alloyed X3CrNiMo13-4 steels showed that they consisted of a single homogeneous phase.