Friction and Wear Behavior of Sintered Fe_3Al Intermetallic-Based Friction Materials

Fe_3Al intermetallic-based friction materials with different compositions were prepared by hot pressing. The phases of the sintered samples were determined by means of X-ray diffraction, the hardness and mechanical strengths of the sintered samples were measured on a hardness meter and a universal material tester. Moreover, the friction and wear behaviors of the sintered samples with different compositions sliding against AISI-1045 steel in a block-on-ring configuration at ambient temperature were investigated on an MM-200 test rig, and the worn surface morphologies of the sintered friction materials were observed on a scanning electron microscope. Besides, the wear mass losses of the counterpart steel ring sliding against different sintered friction material samples were also determined on the same friction and wear tester. It was found that Fe_3Al intermetallic-based friction material had low density, high strength, good oxidation resistance, smooth friction coefficient, and excellent wear resistance, and it led to a small wear of the counterpart steel ring as well. Thus the Fe_3Al intermetallic-based friction material could be used as a friction material of good comprehensive properties. In addition, the sintered friction materials of different compositions were dominated by different wear mechanisms at different sliding stages. Namely, they were characterized by adhesion and abrasive wear at the early-stage sliding during which the wear rates increased slowly with increasing sliding distance. The sintered friction materials were dominated by plastic deformation, crack nucleation and propagation, and brittle spalling at the metaphase sliding during which the wear rates increased sharply with increasing sliding distance. At a large enough sliding distance, the sintered friction materials are characterized by oxidation wear and the rising rate of the wear rates with the sliding distance decreased to some extent, owing to the lubricity of the oxide layer.