METALLOGRAPHIC METHODS FOR REVEALING THE MULTIPHASE MICROSTRUCTURE OFTRIP-ASSISTED STEELS

Classical etching techniques used for the investigation of steel micro structures allow the simultaneous observation of only a restricted num ber of phases. So far, this limitation has not been too detrimental, b ecause most low-carbon steel grades possess a quite simple microstruct ure. The recent interest in the so-called TRIP-assisted multiphase ste els characterized by complex microstructures requires new developments in metallographic methods. This paper proposes an extension of alread y known techniques to allow the study of four kinds of TRIP-aided stee ls. The actual restrictions justifying the development of an improved method are emphasized. in spite of its simplicity, the procedure has; the advantage of allowing the simultaneous observation of the four pha ses that generally compose the microstructure of TRIP-assisted steels; that is, ferrite, bainite, austenite, and martensite. Light and elect ron microscopy as well as diffraction techniques are used to demonstra te the interest of the method. (C) Elsevier Science Inc., 1998.