Interpenetrating Microstructure and Properties of Si₃N₄/Al–Mg Composites Fabricated by Pressureless Infiltration

Abstract

Si₃N₄/Al–Mg composites based on Al–Mg alloy reinforced by ceramic interpenetrating network structure were fabricated via pressureless infiltration technology. Infiltration temperature and infiltration time are the key parameters distinctly effecting on infiltration processes. Moreover, the increasing of Mg content (2–8 wt.%) resulted in an increased amount of infiltration. Microstructural characterization of the composites reveals a special topology of skeleton and good integrity of metal/ceramic interface. The presence of second reinforced phase results in a significant increase in 0.2% offset yield and ultimate tensile strength of composites materials. However, when the volume fraction of reinforcement is large than 6%, there are a distinctly reduction of strength. The presence of additional secondary brittle phase in matrix results in the reduction in ductility and increase in hardness of 3-DNRMMCs. The failure features as cracking and void in reinforcement, interface cracking and interface debonding as well as matrix damage result in the decreases of fracture toughness. With the increases of volume fraction of reinforcement, 3-DRMMC exhibits excellent wear-resistance property.