Microstructural characteristic of hypereutectoid iron alloys melted in ArcMelter furnace

ArcMelter furnace is commonly used as a method for synthesis of amorphous and nanocrystalline materials. Due to easy and precise chemical composition control, also short time of whole process, this method was used to synthesis of new model hypereutectoid iron alloys. Material for the investigation was 90CrV6 steel. The chemical composition of this steel was modified to obtain the increase of carbides volume fraction with preserving the same chemical composition and mechanical properties of the matrix. The melt was conducted at sub atmospheric pressure of argon. The obtained materials were chemically analyzed by the use of optical emission spectrometer. The metallographic analysis was performed by the use of microscope. Phase composition in cast state was analyzed by X-ray diffraction. Chemical composition of the ingots differed from the previously established compositions in the range of 0.08 mass percentage. The high cooling rate resulted in dendritic character of the obtained microstructures. The microstructure of modified tool materials was plate martensite with large amount of retained austenite. The stress induced martensitic transformation in the crack area was observed. Retained austenite destabilization was initiated by the stress relaxation related with material cracking.