Fabrication of protruded laser textures on grey cast iron for enhanced tribological performance under SAE 10W-30 lubrication

Abstract

Shorter component life cycle and emission due to high friction wear of reciprocating components like cylinder liner–piston rings are the main concerns in an engine and generally addressed through different surface modifications. Protruded multi-shaped textures are getting wider popularity nowadays to address these issues. Therefore, the present study proposes an effective fabrication of five distinct laser textures, namely, protruded circular, staggered circular, rectangle, square, and hexagon textures on grey cast iron with variable morphology and contact footprint for prolonged life and tribological performance under SAE 10W-30 lubrication. Five-axis flexi nanosecond ytterbium pulsed laser with optimum process parameters with laser power of 60 W, scanning speed of 2134 mm/s, frequency of 450 Hz, jump speed of 7015 mm/s, and pulse duration of 120 ns was used to fabricate all the textures. Surface morphology of the fabricated textures confirms the quality and accuracy of the fabricated textures. Laser irradiation increases microhardness, whereas protrusions provide lubricant retention along with higher load-carrying ability. Moreover, tribological results confirm the protrusions are favourable in reducing coefficient of friction (COF), frictional force (FF), wear, and mass loss compared to normal surfaces and conventional dimpled textures. Protruded staggered circular texture exhibited the highest reduction of around 38% in COF and FF, compared to base surface, whereas protruded square texture showed the highest reduction in mass loss. It attributes the fact of protrusion dimensions, depth, and fracture of protruded sections also contributed towards improved tribological performance.