Wear Behavior and Hardening Mechanism of Novel Lightweight Fe-25.1Mn-6.6Al-1.3C Steel Under Impact Abrasion Conditions

The aim of the present work was to reveal the wear behavior and hardening mechanism of novel lightweight Fe-25.1Mn-6.6Al-1.3C cast steel under abrasive impact wear with different heat treatments. The impact wear tests were carried out by using MLD-10 abrasive wear testing tester under the same impact wear condition. For this purpose, the cast steel upon quenching (Q) and quenching (1050 degrees C) + aging (Q-A) at 550 degrees C for a different time from 1 to 4 h was chosen to conduct impact abrasive wear tests. It was shown that the best wear resistance of Fe-25.1Mn-6.6Al-1.3C steel under Q-A (2 h) process was about 2.29 times higher than that of under Q process, which results from the fact that the fine nano-size second-phase (Fe, Mn)(3)A1C kappa-carbides tend to precipitate coherently within the austenite matrix under the additional aging treatment. In consequence, the fine nanosize kappa-carbides improved both the initial hardness and wear resistance of the substrate. However, when the specimen was treated at 550 degrees C for longer aging time (4 h), coarse kappa-carbides would precipitate around the grain boundaries, which made the material extremely brittle and decreased the wear resistance. The surface hardening showed Lomer-Cottrell locks, high density of dislocation tangles and dislocation walls; neither martensite nor mechanical twins were observed under the low impact energy condition for both heat treatment processes.