Effects of TiC and residual austenite synergistic strengthening mechanism on impact-abrasive wear behavior of bainite steel

The complex interaction between stress concentration and abrasive embedding is a crucial issue in impact-abrasive wear. By comparing with the conventional tempered martensitic steel, this work attempts to find a correlation between the microstructure and wear resistance of bainitic steel, synergistically strengthened by TiC and the residual austenite (RA). The wear behaviors and work-hardening characteristics of the two steels vary under different impact loads. Bainitic steel has a preferable wear resistance despite its lower initial hardness. This is mainly attributed to the fact that the RA in bainite steel produces a greater work-hardening effect through the transformation-induced plasticity effect and alleviates crack propagation. At the same time, TiC particles resist abrasive embedding into the matrix and effectively decrease the wear failure caused by micro-cutting. EBSD micrograph of: (a) Hardox450 and (b) BS (Here purple is martensite; gray is bainite; red is austenite; yellow is TiC and black lines are grains with a misorientation angle of more than 15°.); True stress-strain curves and corresponding strain hardening rate of (c) the Hardox450 steel and (f) the BS; Wear morphologies of Hardox450 (d–e) and BS (g–h). Compare the conventional tempered martensitic steel, this work is an attempt to find a correlation between microstructure and wear resistance of bainitic steel with TiC and residual austenite synergistic strengthening mechanism. The work hardening characteristics of the two steels were diverse because of the different microstructure. Bainitic steel has preferable wear-resistance despite its lower initial hardness and strength. It is mainly attributed to the RA in bainite steel produces more obvious work hardening through TRIP-effect, and alleviates the crack propagation. Meanwhile, TiC particles resist abrasive embedding into the matrix, the wear failure caused by micro-cutting was depressed effectively. • TiC can protect bainitic steel from abrasive embedment during impact abrasive wear. • The residual austenite in bainitic steel produces more obvious work hardening. • The deformation induced martensitic transformation of residual austenite delayed the crack propagation. • The wear resistance could be effectively improved by TiC particles and retained austenite synergistic effect.