Hardness difference effect of biomimetic surface with hard-soft structure on oil - Lubrication wear resistance

Abstract

Quenched cast iron with different hardness values, as substrates of biomimetic samples from different hardened layers, were selected for this study. To improve the oil - lubrication wear resistance (OWR) of quenched cast iron (QCI) with different hardness values, QCI samples were modified by a two-step laser treatment (TLT) to imitate the shell nacreous layers alternating between soft (substrate) and hard (units) phases. Compared to untreated samples, these modified samples with various soft-hard combinations exhibited different wear patterns, and their wear loss was not always proportional to the average hardness of the corresponding surfaces, while the hardness difference (HDV) between units and substrates had a major impact. For understanding the relationship between the HDV and OWR, three types of substrates coupled with four types of units with a HDV combination variety, where the units were alloyed of C/Cr powders with four types of ratios through TLT, were subjected to reciprocating wear tests under lubrication.

Keywords

• Two-step laser treatment (TLT)
• Different hardness (HDV)
• Oil-lubrication wear resistance (OWR)