Effect of TiB₂/Gr Hybrid Reinforcements in Al 7075 Matrix on Sliding Wear Behavior Analyzed by Response Surface Methodology

Al 7075 alloy matrix reinforced with different weight percentage of titanium borides (TiB₂, 0, 1.5, 3, 4.5 and 6 wt%) and 1 wt% graphite (Gr) hybrid composites were synthesized by in-situ liquid metallurgy route, then the sliding wear characteristics were performed and investigated in this research work. TiB₂ reinforced as 0, 1.5, 3, 4.5 and 6 wt% by the in situ chemical reaction of KBF₄ and K₂TiF₆ salts and 1 wt% Gr with the Al 7075 matrix were added constantly in the melt. Several experiments were carried out to examine the wear behavior of the fabricated composite specimens through a tribometer at ambient temperature. The weight percentage of reinforcement (TiB₂ particles), the applied load, the sliding velocity (SV), and the sliding distance (SD) were selected as process parameters at five different levels. The response surface methodology (RSM) was used to conduct the experiments as RSM is the feasible and accurate method employed for optimizing to set the parameters. To check the significance of the developed model by RSM, ANOVA and confirmatory tests were also accomplished. FESEM surface morphology was also carried out to illustrate the uniform dispersion of the TiB₂–Gr particulates in Al 7075 matrix. The predicted wear characteristics from the developed model were well agreed with the experimental results. The obtained results were explained that both the increase in the percentage of RF and SV have dropped the wear loss (WL) curve whereas the load at all SVs and the SDs were uplifted the WL. The worn surface morphology explained that the adhesive mechanisms were dominated during the sliding wear test. Further, severe and mild wear occurred during higher load and lower load respectively.