Fabrication and wear behavior of TiC/TiB2-reinforced NiAl intermetallic matrix composites

Abstract

Combustion synthesis (CS) is a well-known technique for manufacturing intermetallic compounds and intermetallic-matrix composite materials. This research focuses on fabricating NiAl-matrix composites with varying TiC/TiB2 contents as reinforcement, achieved by the combustion synthesis method. The chemical reactions that yield the final NiAl–TiC–TiB2 compounds were interpreted using thermodynamic calculations. The phase analysis and morphology of the composites were investigated using X-ray diffractometry (XRD) and scanning electron microscopy (SEM) characterization techniques, respectively. The findings demonstrate that the NiAl matrix contains evenly distributed TiC–TiB2 ceramic-based particles, and no oxidation of reactants occurred during the combustion reaction. With an increase in the TiC–TiB2 reinforcement phases from 0 to 15 wt %, the hardness of the NiAl–TiC–TiB2 product significantly rose from 496 to 1015 Vickers, while the porosity increased from 24% to 39%, attributed to the reduced quantity of melted NiAl available to fill the pores. Examining tribological behavior in synthesized composites involved combining experimental-numerical methods, utilizing sliding wear tests and artificial neural network (ANN) modeling. The wear results revealed decreasing wear rates with reduced loads (from 35 N to 25, and 15 N) and higher TiC/TiB2 ceramic content. Iron traces at C0 and C10 worn samples were 2.47 and 26.18 wt % respectively, which indicates enhanced hardness. The experimental data were used to train and test an artificial neural network (ANN) and statistical analysis revealed a remarkable accuracy of 91% for the ANN model in predicting friction coefficients within SHS-processed composites, as indicated by the R2 value of 0.91 and a MAPE of 6.47.