Microstructure, properties and application of YAl₂ intermetallic compound as particle reinforcements

An yttrium aluminum (YAl₂) intermetallic compound ingot was prepared in an induction furnace under vacuum. The microstructure of YAl₂ ingot was characterized by optical microscopy, scanning electron microscopy, and X-ray diffraction. The load bearing response of YAl₂ intermetallic was investigated and compared with SiC ceramic by indentation combined with optical microscopy and scanning electron microscopy. Additionally, the tensile properties of the Mg-Li matrix composites reinforced with ultrafine YAl₂ particles fabricated by planet ball milling were tested. The results show that the intermetallic compound ingot in this experiment is composed of a main face-centered-cubic structure YAl₂ phase, a small amount of YAl phase, and minor Y and Al-rich phases. YAl₂ intermetallic compound has excellent stability and shows better capability in crack resistance than SiC ceramic. The YAl₂ intermetallic compound has better deformation compatibility with the Mg-14Li-3Al matrix than SiC reinforcement with the matrix, which leads to the superior resistance to crack for YAl_2p/Mg-14Li-3Al composite compared to SiC_p/Mg-14Li-3Al composite.