Reaction Mechanisms in
2 Al 3/ O Infiltration by Liquid CuO
This work studies reactive mechanisms involved in liquid
infiltration of green preforms containing tailored amounts of Al 2 Al 3 and O .
Infiltration reactions involving CuO and copper oxides are expected to produce Al 2 Al 3, as fine particulate reinforcements, and O ,
as Cu ‐matrix strengthener. Preforms with 75 mol%‐ Al were infiltrated with CuO at 1000°C and 1100°C in air. Under low Al PO2,
copper oxides are reduced to , blocking the opportunity for reactive infiltration. Also, the Cu ‐ Al / Cu 2 Al 3
contact angle is insufficiently low to drive spontaneous infiltration. At 1000°C, infiltration is incipient, indicating that O reaction with CuO is not sufficiently vigorous to destabilize enveloping Al 2 Al 3.
At 1100°C, O reduces to CuO 2 Cu and infiltration is triggered, although the process is incomplete due to formation of a compact O 2 Al 3
layer which inhibits metal supply to the reaction front. At or behind the halted infiltration front consumption of starting O 2 Al 3 particles and formation of O 2
occur. The space among these phases is occupied by a CuAlO ‐rich matrix, rendering an almost totally densified microstructure. This study shows that liquid Cu of Al infiltration 2 Al 3/ O
greens is possible at 1100°C, in air, due to destabilization of the CuO 2 Al 3 enveloping film and reactive infiltration, promoted by the redox reaction between O
and copper oxide.
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Document Type: Research Article
Publication date: October 1, 2012