What elements or microstructures mainly determine the wear resistance of nickel-based alloys?
Chromium (Cr): It forms a dense and hard oxide film (Cr₂O₃) on the alloy surface, which effectively reduces adhesive wear and oxidative wear, and improves the alloy's anti-adhesion ability.
Tungsten (W) / Molybdenum (Mo): These elements form hard intermetallic compounds (e.g., Ni₃W, Ni₃Mo) and solid-solution strengthen the nickel matrix, significantly increasing the hardness and anti-abrasive wear performance of the alloy.
Carbon (C) / Boron (B): They react with strong carbide-forming elements (Cr, W, Mo, etc.) to generate hard phases such as carbides (MC, M₆C) and borides. These hard phases are uniformly distributed in the matrix, acting as wear-resistant barriers to resist the cutting and extrusion of abrasive particles.
Aluminum (Al) / Titanium (Ti): They form stable γ' strengthening phases (Ni₃Al, Ni₃Ti) through precipitation strengthening. The coherent relationship between the γ' phase and the nickel matrix enhances the hardness and deformation resistance of the alloy, thereby improving wear resistance.
Dispersed Hard Phases: Uniformly distributed carbides, borides, and intermetallic compounds are the core of wear resistance. The size, morphology, and distribution of these hard phases directly affect the wear resistance-fine and evenly dispersed hard phases have better wear-resistant effects.
Precipitation-Strengthened Matrix: The γ' phase precipitated in the nickel matrix can effectively hinder the movement of dislocations, improve the hardness and strength of the matrix, and prevent the matrix from being worn out first, thus protecting the hard phases.
Dense Oxide Film: A continuous and stable oxide film formed on the surface during service can separate the alloy from the friction pair, reduce direct contact between metals, and alleviate adhesive wear and oxidative wear.
