Raman investigation of chemical reaction product in thermal‐treated SiCf/C/Mo/Ti6Al4V composite

SiC fiber‐reinforced titanium matrix composite (TMC) is an interesting material for aerospace industry because of its excellent properties. Characterization of their interfacial reaction product is principal to further optimization of the TMCs. Here we report application of Raman spectroscopy to identify reaction products and their microstructural details in thermal‐treated SiC_f/C/Mo/Ti6Al4V composite. Meanwhile TEM is performed to help explain phenomena in Raman result. Raman line scanning along interface indicates thickness of two sublayers (Ti₅Si₃(C_x) layer next to SiC fiber and TiC_x layer next to matrix). The main Raman result of phase distribution is confirmed by TEM. While a 300‐nm Ti₃SiC₂ layer whose Raman features are similar with nearby Ti₅Si₃(C_x) layer is also detected. Raman peakshift in Ti₅Si₃(C_x) layer possibly results from residual stress or/and microstructural evolution caused by carbon solution. No evidence indicates Mo participation of interfacial reactions. However, Mo diffusion changes phase distribution of matrix alloy and affects interfacial reaction indirectly. Meanwhile, TEM and Raman results indicate that particles are TiC_x and defective Ti₃AlC₂. Raman features of Ti₃AlC₂ particles differ from that of bulk material, which is attributed to defects. Although Ti₃AlC₂ formation mechanism is ambiguous, it possibly relates to TiC_x formation nearby. Copyright © 2014 John Wiley & Sons, Ltd.