Effects of Unreacted Ti Particles on the Dry Sliding Tribological Behavior of Squeeze-Cast (SiCp + Ti)/7075Al Hybrid Composites Under Different Applied Loads

The effects of Ti particles on the dry sliding tribological behavior of squeeze-cast (SiCp + Ti)/7075Al hybrid composites were investigated. The incorporated Ti particles exerted significant influence on the tribological behavior of the composites except for the wear mechanism. Ti particles could hinder the crack of SiC particles on the contact surface of the composites, which made the composites show an obvious break-in stage at the beginning of the test. The friction coefficient showed varied amplitude and wave fluctuation trends due to the interactions among the debris, the composite and the counterpart without the influence of Ti particles. Moreover, the incorporated Ti particles exerted different effects on the wear resistance of the composites under different applied loads. Ti particles, which could hinder the fracture of SiC particles and the formation and propagation of the cracks in the subsurface deformation, improved the wear resistance of the composites under low applied load. The interfacial stresses in the vicinity of Ti particles increased sharply due to the different strains between the matrix and Ti particles under high applied load, which eventually invalidated the strengthening effects of the Ti particles. Finally, the wear resistance of the composites was deteriorated with the increase in applied load.