In-Situ High Temperature Microstructural Analysis During Tempering Of 42crmo4 Using Transmission Electron Microscopy

In the present work, investigations of the microstructural changes were carried out during hardening and tempering of 42CrMo4 (1.7225) steel. Using transmission electron microscopy, the hardened state was examined initially. Following this, the material was incrementally heated in a heated specimen holder to 580 degrees C. Diffraction patterns were recorded at regular intervals in order to analyse and document the changes from a martensitic structure to a ferritic structure. The characteristic tempering stages were identified for the material and assigned to a temperature range. Moreover, thermal activated diffusion processes were detected above 500 degrees C.