In this work, the effects of 75 mm thick cast iron, (casting mould YIV) composition (Cu) and heat treatment were investigated on the microstructure and mechanical properties (hardness, elongation, tensile strength, yield strength) of ductile iron castings. As a result of adding Cu, the amount of pearlite is at 80% reduces of amount of ferrite. Normalizing of non-alloy cast iron increases the amount of pearlite to 70%. It also, increases tensile strength (659 MPa) and hardness (248 HB). Studied metallographic crossections were made from the grip sections of the tensile specimens. The structure composition and the characteristics of graphite were determined by computer image analysis. Measurements of graphite of non-alloy cast iron after normalizing and in cooper cast iron indicate the approximate amount of precipitates of graphite and their approximate average diameters. The applied normalizing and the additive alloy (Cu) were established to give comparable mechanical properties and structure of matrix in thick-walled castings.

The paper presents adaptation problem of lamellar/rod growth of eutectic. The transformation of eutectic microstructure was investigated systematically. A interpretation of the eutectic growth with theory minimum entropy production was presented.

Directional solidification of ledeburite was realised out using a Bridgman’s device. The growth rate for movement sample v=83.3 μm/s

was used. In one sample the solidification front was freezing. The value of temperature gradient in liquid at the solidification front was

determined. Interfacial distance λ on the samples was measured with NIS-Elements application for image analysis.

Fe - 4,25% C alloy was directionally solidified with a constant temperature gradient of G = 33,5 K/mm and growth rate of v = 83,3 μm/s (300 mm/h) using a vacuum Bridgman-type crystal growing facility with liquid metal cooling technique. To reveal more detailed microstructure, the deep etching was made. This was obtained in the process of electrolytic dissolution. The microstructure of the sample was examined on the longitudinal and transverse sections using an Optical Microscope and Scanning Electron Microscope. Using the Electron Backscattered Diffraction technique, phase map and analysis of phase were made. In this paper the analysis of Fe-C alloy eutectic microstructure is presented. Regular eutectic structure was obtained. The fracture surfaces show lamellar structure. Microscopic observation after electrolytic extraction indicates that the grains of longitudinal shape of eutectic cementite have been obtained. These grains are characterized by layered construction with many rounded discontinuities.

In a vacuum Bridgman-type furnace, under an argon atmosphere, directionally solidified sample of Fe - C alloy was produced. The pulling

rate was v = 83 μm/s (300 mm/h) and constant temperature gradient G = 33,5 K/mm. The microstructure of the sample was examined on

the longitudinal section using an Optical Microscope and Scanning Electron Microscope. The X-ray diffraction and electron backscatter

diffraction technique (EBSD) have been used for the crystallographic analysis of carbide particles in carbide eutectic. The

X-ray diffraction was made parallel and perpendicular to the axis of the goniometer. The EBSD shows the existence of iron carbide Fe3C

with orthorhombic and hexagonal structure. Rapid solidification may cause a deformation of the lattice plane which is indicated by

different values of the lattice parameters. Such deformation could also be the result of directional solidification. Not all of the peaks in

X–ray diffractograms were identified. They may come from other iron carbides. These unrecognized peaks may also be a result of the

residual impurity of alloy.

Directionally solidified sample of Fe-Fe3C eutectic alloy were produced under an argon atmosphere in a vacuum Bridgman-type furnace to

study the eutectic growth with v = 167 μm/s pulling rate and constant temperature gradient G = 33.5 K/mm. Since how the growth texture

of eutectic cementite is related to its growth morphology remains unclear, the current study aims to examine this relationship. The technique

such as X-ray diffraction, have been used for the crystallographic analysis of carbide particles in white cast irons.

Directional solidification of the Fe - 4,3 wt % C alloy was performed with the pulling rate equal to v=83 μm/s. Sample was frozen during

solidification to reveal the shape of the solid/liquid interface. Structures eutectic pyramid and spherolitic eutectic were observed. The

solidification front of ledeburite eutectic was revealed. The leading phase was identified and defined.

In order to determine the leading phase of the Fe - 4.25% C eutectic alloy, the method of directional crystallization, which allows to study the character of the solid / liquid growth front, was used. Examined eutectic was directionally solidified with a constant temperature gradient of G = 33,5 K/mm and growth rate of v = 125 μm/s (450 mm/h). The Bridgman technique was used for the solidification process. The sample was grown by pulling it downwards up to 30 mm in length. The alloy quenched by rapid pulling down into the Ga-In-Sn liquid metal. The sample was examined on the longitudinal section using a light microscope and scanning electron microscope. The shape of the solid/liquid interface and particularly the leading phase protrusion were revealed. The formation of the concave – convex interface has been identified in the quasi-regular eutectic growth arrested by quenching. The cementite phase was determined to be a leading phase. The total protrusion d is marked in the adequate figure.

One type of spheroidal cast iron, with additions of 0.51% Cu and 0.72% Ni, was subjected to precipitation hardening. Assuming that the

greatest increase in hardness after the shortest time of ageing is facilitated by chemical homogenisation and fragmentation of cast iron

grain matrix, precipitation hardening after pre-normalisation was executed. Hardness (HB), microhardness (HV), qualitative and

quantitative metalographic (LM, SEM) and X-ray structural (XRD) tests were performed. The acquired result of 13.2% increase in

hardness after ca. 5-hour ageing of pre-normalised cast iron confirmed the assumption.