Surface failure behavior of 70Mn martensite steel under abrasive impact wear

• The strain-hardening effects were analyzed by Micro-hardness profiles.
• The impact wear mechanism was analyzed.
• The mechanism of WEL is formation of twin martensite and accumulation of dislocations.
• The delamination and fracture result were the primary surface failure mechanism.

The aims of this paper are to reveal the surface failure behavior of 70Mn martensite steel under abrasive impact wear by impart wear tests. The wear tests were performed with the MLD-10 abrasive wear testing machine, using SiO2 abrasive with three different impact loads for 30000 cycles. Worn surfaces and white-etching layers (WEL) were analyzed by scanning electron microscopy, x-ray diffraction and transmission electron microscopy, and the abrasive impact wear mechanism was analyzed. Strain-hardening effects beneath the contact surfaces were researched by Micro-hardness profiles. Results indicated that the main formation mechanism of white-etching layers (WEL) in test steel were the formation of twin martensite and accumulation of dislocations attributing to plastic deformation during impact wear tests. The thickness and hardness of WEL were both increased with test load, which led to an increased brittleness of WEL. Under the effects of impact load, the micro-cracks initiated at subsurface and extended to surface, eventually led to delamination and fracture. Therefore, the delamination and fracture resulting from plastic deformation fatigue were the primary surface failure mechanism of the steel at abrasive impact wear.