Structure of ADI Cast Iron as a Cast “in situ” Composite Reinforced with TiC Ceramic Particles

This paper presents a novel technology for the production of a casting material, which is an “in situ” composite on an ADI iron matrix reinforced with titanium carbide particles. As a result of the initiated Self-propagating High-temperature Synethesis reaction in Bath (liquid metal) of the type “solid Ti” – “solid C” type, led to the formation of ceramic phases in the form of titanium carbides. This method, allowed the synthesis of a cast composite based on ductile cast iron and, after subsequent heat treatment, the transformation of this material into ADI cast iron. The greatest advantage of “in situ” composites is that they are produced in a one-step metallurgical process, which is characterised, among other things, by: high thermodynamic stability, synthesis of a reinforcing phase in a metal bath, small size of ceramic particles with the possibility of controlling their dimensions by reaction kinetics parameters during the synthesis process. In this study, metallographic analysis of the composite obtained, both in the initial state and after heat treatment, was carried out using optical and scanning electron microscopy. An analysis of the chemical composition in the micro-area was carried out using the EDS method, the chemical composition was studied using the XRF spark X-ray fluorescence method, and the proportion of graphite and the carbide phase, i.e. titanium carbide TiC, was determined. The results obtained confirmed the possibility of obtaining the composite material via the SHSB reaction route. The heat treatment results showed that the carbides are thermodynamically stable and do not dissolve at temperatures designed for the production of ADI cast iron. The SHSB reaction guarantees a uniform distribution of titanium carbides on the ADI cast iron matrix.