Microstructural Characterization of Martensitic Q&P Steels – a Comparison of Etching Techniques and Electron Backscatter Diffraction

Abstract A wide range of methods and procedures exists to characterize microstructures and to quantify phases. This work presents a comparison between light microscopic examinations as a function of different etching methods and electron backscatter diffraction analyses. The procedures used in this context were etching with V2A solution, Kalling I and Beraha II etchants. The objective was to quantify the austenite phase in Q&P heat treated X46Cr13. The Q&P heat treatment allows to achieve high mechanical strengths (for X46Cr13 approx. Rp0.2 = 1750 MPa) alongside high elongations at break (A = 14 %). This can be attributed to a combination martensite tempering and the TRIP effect. The required specific ratio of martensite and austenite can be established by the heat treatment. In order to define the heat treatment's optimal parameters, the mechanical characteristic values need to be determined and comprehensive phase fraction determinations must be performed. Beraha II provided particularly promising resul...