Microstructure and wear of cast (Al-Si alloy)-graphite composites
1989; Elsevier BV; Volume: 133; Issue: 1 Linguagem: Inglês
10.1016/0043-1648(89)90122-1
ISSN1873-2577
AutoresS. Das, Somuri V. Prasad, T. Ramachandran,
Tópico(s)Tribology and Wear Analysis
ResumoGraphite-particle-dispersed Al-Si alloys have potential for a variety of antifriction applications. In the present investigation, two Al-Si alloys (LM13 of near eutectic and LM30 of hypereutectic composition) were chosen as matrix alloys and composites were prepared by casting. Composites and matrix alloys were heat treated to produce different morphologies of silicon ranging from plate-like in die-cast alloys to near spherical in heattreated alloys. Wear tests were conducted, under both dry and partially lubricated conditions, with SAE30 oil on a pin-on-disc wear test apparatus, against a rotating steel (EN25) counterface. In partially lubricated wear tests, the sliding velocity V was varied from 1.4 to 4.6 m s−1 and the applied pressure P from 1.0 to 5.0 MPa. P-V limits of all matrix alloys and composites with different microstructures were evaluated. Heat-treated composites were found to possess superior wear properties (wear rate, seizure resistance and P-V limits) as compared with those of die-cast composites and matrix alloys. Worn surfaces of heat-treated composites showed the presence of a graphite film while those of die-cast alloys and composites showed surface fracture. The role of graphite particle dispersion and the morphology of silicon on the sliding wear behaviour is discussed.
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