Effects of in situ TiB2 particle on microstructures and mechanical properties of AZ91 alloy

The effects of in situ TiB2 particle fabricated from Al-K2TiF6-KBF4 system via Direct Melt Reaction (DMR) technology on microstructure and mechanical properties of AZ91 alloy are investigated. The results indicate that the sizes of α-Mg sosoloids are decreased and the morphologies are orbed with in situ TiB2 particle addition; the amounts of β-Mg17Al12 are decreased and the morphologies are granulated. The mechanical properties tests show that the tensile strength σb, elongation δ and HB hardness are 221.70 MPa, 3.87% and 75.49 kgf/mm2, which are 1.19, 0.98 and 1.22 times to that of without Al-TiB2 addition, respectively. The effect mechanisms are discussed.