The study aimed to investigate the effect of different atmospheres and compositions of aluminum alloys in the fabrication of Al-B4C composites by melting infiltration into porous boron carbide preforms. At first, powder of B4C with 20 µm together with polymeric material was fabricated in porous preform by gel casting method. Then the preform was pyrolyzed at 900°C for 3 hours in a nitrogen atmosphere oven. Next, three different compounds, including pure Al, Al6061, and Al-13.8% Mg2Si, were infiltrated into the preform inside the furnace under an oxidizing atmosphere, vacuum, and neutral gas. To characterize the samples, XRD, SEM, and EDAX analyses and the percentage of porosity of the samples were performed by the Archimedes method. The results showed that the presence of a magnesium atmosphere inside the furnace makes the infiltration process possible due to increasing the wetting agent of metal with ceramic and breaking the alumina oxide shell. Al-13.8% Mg2Si eutectic alloy showed the ability to penetrate the porous body and make a highly dense body. Simultaneous use of magnesium atmosphere and high infiltration temperature prevented the formation of carbide phases.
Type of Study:
Research |
Subject:
Structural Oxide and Non-Oxide Ceramics Received: 2023/11/19 | Accepted: 2024/01/30