Effect of Variation of Martensite with a Constant Carbon Content on Mechanical Behavior and Sliding Wear of Dual Phase Steels

In a dual phase (DP) steel, an increase in the martensite volume fraction leads to a decrease in its carbon content, and hence, elucidating the effect of martensite content on the mechanical and tribological behaviors is not possible. For the first time, the present work dealt with this subject by maintaining a constant amount of carbon in different volume fractions of martensite. Tribological properties was evaluated via a pin on disk sliding tribometer. The study of wear tracks and debris revealed oxidative wear as the dominant wear mechanism. Increasing normal load from 10 to 30 N resulted in a decrease in the specific wear rate, which was related to the high work-hardening capacity. This resulted in higher surface hardness, accommodating the formation of a more durable tribofilm on the surface, and a lower coefficient of friction. However, the increase in normal load from 30 N to 60 N resulted in an increase in the specific wear rate and reduction of oxide coverage on the sliding surface due to high surface stresses. The worn debris in the running-in and steady-state stages were mainly identified as metallic and Fe 3 O 4 oxide, respectively.