This paper reports on a study to investigate the creation of a mixed microstructure consisting of proeutectoid ferrite, bainite, and austenite in a medium carbon high silicon steel. The microstructure was produced through the use of a continuous cooling process at a moderate cooling rate from the austenitizing temperature range to room temperature. The investigation also examined the influence of this microstructure on the mechanical properties of the material. Test results indicate that the developed steel has better mechanical properties compared to commercially available dual phase steels.

Austempered Ductile Cast Iron (ADI) has emerged as an important engineering material in recent years. It has a combination of high strength, good ductility, good fatigue strength and fracture toughness. Because of these excellent properties, it is now extensively used in many structural applications such as automotive components, earth moving machineries etc. An investigation was carried out to develop ADI with a nano scale microstructure. This was achieved by high temperature deformation and subsequent austempering of ductile cast iron. The effect of processing parameters such as deformation temperature, strain rate, austempering temperature and austempering time on microstructural features such as volume fraction of phases, size and distribution of phases were examined.

An investigation was carried out to examine the influence of cryogenic processing on the microstructure and mechanical properties of Austempered Ductile Cast Iron (ADI). ADI has emerged as a major engineering material in recent years because of its many attractive properties. These include high yield strength with good ductility, good fatigue strength, fracture toughness and wear resistance. In this investigation, compact tension and cylindrical tensile specimens were prepared from ductile cast iron as per ASTM standards and were austempered at a lower bainitic temperature of 288°C (550°F). These specimens were then cryogenically processed. The mechanical properties and fracture toughness of these samples were evaluated and compared with the noncryogenically treated samples. The influence of cryogenic heat treatment on the microstructure of these samples was also examined. Test results show that the cryogenic processing can improve the mechanical properties without compromising the fracture resistance of the material.