Fabrication of Ceramic-Metal
functionally Graded Materials |
High order
step wise functionally graded materials Al2O3-Ti are fabricated.
These materials combine the high fracture toughness of Ti phase
and the relatively low density of Al2O3 and stand for candidate
materials for harsh mechanical and thermal environments. The
techniques of powder technology are utilized to fabricate these
materials that composed of five graded layers of Al2O3-Ti
phases. Al2O3 increasing linearly across these layers (0, 25,
50, 75 and 100wt%respectively). The green specimens are composed
of Al2O3-TiH2 layers and the sintered specimens are composed of
graded Al2O3-Ti. Spark Plasma Sintering technique is utilized
for sintering of the graded green specimens. The best sintering
conditions is found at 1500°C for 30 minute of sintering that
gives apparent density of 4.25 g/cm3, porosity of 1.28% and
diametric expansion of 1.58%. Optical microscopy shows. |
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