Etching techniques for characterizing the phases of low-alloy dual-phase and TRIP steels

Dual-phase and TRIP steels constitute a new generation of high-strength steels which feature a superior combination of strength and ductility. This primarily allows steel to strengthen its position as a structural material for light-weight constructions. The number and disposition of hard second phases such as martensite, bainite, and residual austenite determine the property profile of those multiphase steels in a way similar to the principle of composite materials. A contribution is made to the comprehension of the etching technology and, hence, a correct interpretation of the microstructural configuration of DID and TRIP steels by conceiving model considerations on how to erode material by etching in a selective way and contrast it by etching with colour film deposition, and via a verification of those models by applying different etchants.