Effects of temperature on the microstructure and physico-mechanical properties of TiNiAl-SiC composite by spark plasma sintering technique

Effect of temperature on microstructure and physico-mechanical properties of Ti-Ni-Al/SiC metal matrix composite is investigated using spark plasma sintering technique. The sintering was done at 800 degrees C, 900 degrees C, and 1000 degrees C respectively at a fixed heating rate of 100 degrees C min(-1) and under a compaction pressure of 40 MPa with 10 min holding time. Scanning electron microscopy (SEM) with EDX was used to study the microstructure and phase transformation of sintered MMCs, while densification and microhardness testing were used to study the physical properties. Results indicated an enhancement in the mechanical properties of sintered Ti-Ni-Al/SiC MMCs as temperature increases and were found to be superior to that of Ti-Ni-Al (control) alloy sample. The constituent phases of the composite detected by the XRD are the binary Ni (TiO3), Ti3SiC2 and ternary Ni4Si7 Ti-4 and Ni2Ti4O. Samples sintered at 1000 C showed the largest crystallographic peak of Ni (TiO3) and Ni4Si7Ti4 owing to the rapid kinetic movements of elemental atoms during the sintering process. The metal composite sintered at 1000 degrees C was observed to give the optimum densification of 99.12% and hardness of 400.03HV (similar to 4 GPa), due to the formation of different hard intermetallics compounds.