Dry sliding wear of NiAl

The dry sliding wear behavior of the B2-structured (ordered body-centered cubic) compound NiAl has been studied. Pin-on-disk experiments were conducted at room temperature in air using pins made from extruded NiAl with compositions of 50, 48, and 45 at.% aluminum. Partially stabilized zirconia was the disk material. Wear rate measurements showed an inverse relation between wear and hardness. Hardness increased with increasing nickel content as the composition moved away from stoichiometric composition. Friction results indicate higher friction coefficients for Ni-50Al than for either Ni-48Al or Ni-45Al. Surface examinations of the pin wear scars, by both optical microscopy and scanning electron microscopy, show the wear process of NiAl is dominated by plastic deformation in all compositions, with little evidence of material loss by brittle fracture.