Alexander Glage

Microstructure of austenitic stainless steels of various phase stabilities after cyclic and tensile deformation

Abstract The microstructures of two metastable high-alloyed CrMnNi cast TRIP steels and a stable AISI 316L austenitic stainless steel were studied in detail after tensile and cyclic deformation. Electron backscattered diffraction was employed to localize the martensitic phase transformation and electron channelling contrast imaging to describe the typical dislocation arrangements. These were complemented by transmission electron microscopy and by scanning transmission electron microscopy performed in a scanning electron microscope. The TRIP steel with the lowest austenite stability shows a more pronounced martensitic phase transformation realized from the austenite via the intermediate formation of ∊-martensite. Martensitic phase transformation also occurred in the stable 316L austenitic stainless steel with a small volume fraction of α′-martensite, but only with cyclic deformation at low temperatures and/or at very high plastic strain amplitudes.

Observation of stacking faults in a scanning electron microscope by electron channelling contrast imaging

Abstract The electron channelling contrast imaging technique was applied in a scanning electron microscope equipped with a field emission gun and high beam current mode for imaging stacking faults, in particular in two different variants of cast TRIP steel after tensile and cyclic deformation. Besides well developed deformation bands, individual stacking faults with low dissipation width were observed in the metastable austenitic matrix.