Using metallic additives as a bonding layer to produce Ti-based laminated composites via spark plasma sintering
Ti laminated composites were successfully prepared by employing metallic additive powders between Ti sheets, and using the spark plasma sintering process. Mo, Cr, Si and Co were inserted between Ti layers, and spark plasma sintering was carried out at 1250 °C. Regarding the Ti–Si laminated composite, the final products comprised divided sintered Si and Ti sheets which were not stuck together. A new sample was prepared at a temperature higher than 1850 °C with the appropriate bonding of layers. The XRD patterns revealed dominant Ti peaks in Ti–Cr and Ti–Mo, while, in the intermetallic compounds between Ti and metallic additives of Co, Si peaks were dominant. The FESEM images taken from the samples’ cross-section demonstrated the ultra-short-range diffusion of Mo into the Ti sheets. The process was amplified from Cr additives to Co; it appeared that the laminated structure was changed into a uniform one of the Ti–Co alloy. Regarding the Si additive, the laminated structure turned into the intermetallic of Ti5Si3–Ti5Si4 islands and seemed to be the composite. An analysis of the mechanical properties also showed the highest Vickers hardness of 1121 ± 32 HV1 for the Ti–Si sample in terms of the intermetallic nature of the formed sample, whereas the highest bending strength of 998 ± 16 MPa was achieved in the Ti–Cr laminated composite.