Investigation of Friction and Wear Behavior of Cast Aluminum Alloy Piston Skirt with Graphite Coating Using a Designed Piston Skirt Test Apparatus

Abstract

A piston skirt friction and wear apparatus that simulates the contact and the relative motion of piston and cylinder liner in a real engine has been designed and constructed. With this apparatus, the friction and wear behavior of a cast aluminum alloy piston with a graphite coating under different loads was studied, and the effectiveness of the apparatus was confirmed. The total wear of the piston skirt was higher under a higher load, and the upper part of the skirt surface (around the height of the piston pin) was worn more severely. The wear mechanisms were studied and, based on the test results and surface analyses, three main wear modes were believed to occur in the wear process of the piston skirt: abrasive, adhesive, and fatigue wear. The effects of skirt profile design, coating, and surface texturing on the friction and wear behavior of the piston skirt can be investigated well using the proposed apparatus, which can truly reflect actual working conditions and is useful to improve the tribological performances of piston skirts.

Room- and High-Temperature Fatigue Strength of the T5 and Rapid T6 Heat-Treated AlSi10Mg Alloy Produced by Laser-Based Powder Bed Fusion

“…A final polishing step with 2500 grit emery paper was performed in the direction parallel to the specimen axis to remove any circumferential marks (Figure 2b,c). The gauge section of the specimens was polished to consider near-netshape surfaces in high-technological applications that require extremely low and controlled roughness [16,31,32].…”

“…A final polishing step with 2500 grit emery paper was performed in the direction parallel to the specimen axis to remove any circumferential marks (Figure 2b,c). The gauge section of the specimens was polished to consider nearnet-shape surfaces in high-technological applications that require extremely low and controlled roughness [16,31,32]. The roughness was evaluated on all the tested specimens using stylus profilometry (Hommelwerke T2000, Schwenningen, Germany, radius of curvature of the stylus tip equal to 5 μm) on the grip section, which was polished by the same steps employed for the gauge length and used as a reference.…”

Influence of Electroless Nickel—DLC (Diamond-like Carbon) Multilayer Coating on the Mechanical Performance of the Heat-Treated AlSi10Mg Alloy Produced by Powder Bed Fusion-Laser Beam

“…However, even though the advantages of multilayer coatings on the tribological properties of Al alloys are widely documented [11,23,[27][28][29][30], there are no studies on the combined tensile and fatigue performance of Ni-P + DLC multilayers. Given the high mechanical stress to which Al-based structural components are subjected, it is essential to know how the mechanical properties of parts change in coated and uncoated conditions.…”