Microstructure and Reaction Mechanism of Multi-Laminated Ti-(SiCp/Al) Composites Subjected to Annealing at 1300°C

The multi-laminated Ti-(SiCp/Al) composite was produced by hot press and subsequent hot roll bonding of Ti and SiCp/Al foils. The microstructure evolution of the composite in reaction annealing was investigated by scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometer (EDX) and X-ray diffractometer (XRD). The results show that after the reaction annealing at 1300°C for 3h, the Ti and SiCp/Al foils were completely consumed and transformed into the TiAl composite with a microlaminated structure. The microlaminated microstructure of the composite is composed of Ti3Al/(TiAl+Ti5Si3p)/Ti5Si3/duplex-phase (TiC+Ti3AlC) layers. The reaction mechanism is elucidated by employing the reaction model.

The Fabrication of Titanium Aluminide Matrix Composite Sheet by Rolling and Reaction Annealing

In this work, Ti5Si3 and TiC particle reinforced titanium aluminide matrix composite sheet was fabricated by rolling and reaction annealing using the starting materials of SiCp/Al composite and pure titanium sheet. The deformation compatibility of both starting materials and microstructure evolution during reaction synthesis were studied. The results show that titanium has the similar deformability with SiCp/Al composite via the introduction of SiC particles and the selection of proper rolling temperature. Titanium aluminide matrix composite reinforced by Ti5Si3 and TiC was synthesized by reactions during the annealing. The reactions include the formation of titanium aluminide matrix by the diffusion synthesis between titanium and aluminum, as well as reinforcements (Ti5Si3 and TiC) by in-situ reaction between SiC and titanium.