Interfacial Characteristics and Mechanical Properties of TiAl4822/Ti6Al4V Metal-Intermetallic Laminate Composite...

In this work, the TiAl4822/Ti6Al4V metal-intermetallic laminate (MIL) composite was fabricated using vacuum hot pressing (VHP). The interfacial morphologies and mechanical properties of the composites were investigated. No discernible defect was observed in the well-bonded interface region. This interface region comprised two distinct areas: the Ti₂Al (6 μm) region near the TiAl layer and the Ti₃Al (4 μm) region near the Ti6Al4V layer. Electron backscatter diffraction analysis revealed that dynamic recrystallization (DRX) took place at the interface during the hot pressing process. The ductile brittle nature of Ti6Al4V and TiAl4822 layers and the formation of fine grains within the interface are conducive to enhancing toughness and tensile strength. Room temperature tensile testing exhibited that the tensile strength of TiAl4822/Ti6Al4V MIL composite was 636.9 MPa, approximately 225 MPa higher than single TiAl4822 alloy. The Ti6Al4V layer, as well as the formation of fine grain interface, effectively inhibited further propagation of the main crack through crack passivation, crack deflection, and load transformation. The bending strength of the TiAl4822/Ti6Al4V MIL composite was 1114.1 MPa. The fracture toughness of the TiAl4822/Ti6Al4V MIL composite reached 33.15 MPam^1/2, which increased by 78.2% compared with single TiAl4822 alloy.