Martensitic transformation and work hardening of metastable austenite induced by abrasion in austenitic Fe-C-Cr-Mn-B alloy - a TEM study

摘要

The martensite transformation and work hardening of metastable austenite induced by abrasive wear in an austenitic Fe - C - Cr - Mn - B alloy were studied by TEM. The results -show that an α' martensitic transformation occurred to form an elongated and equiaxial cellular dislocation substructure and the untransformed austenite matrix produced an equiaxial cellular dislocation substructure on the abraded surface. Electron diffraction patterns of the abraded material are composed of diffraction rings with series of broken arcs resulting from a fine grain structure and the deformation texture. The work hardening zone of austenite at the subsurface reveals heavy slip bands and deformation faults, at which the dislocations pile up. Examples of e martensite induced by abrasive wear can be detected. The α' martensite transformation and metastable austenite work hardening should bring about an increase in surface hardness and wear resistance. Additionally, the cellular dislocation substructure of α' and 7 have a significant effect on increasing the hardness of the wear surface. Observation by TEM indicates that the α' martensite transformation happens more easily in the austenite matrix near the carbide (Fe, Cr){sub}7C{sub}3 as a result of the depletion of carbon and chromium.