Improvement of Mechanical Properties in Austempered Ductile Iron by Cryogenic Treatment

The focus of this investigation was on examining the effect of cryogenic treatment on the microstructure and mechanical properties of Austempered Ductile Cast Iron (ADI) with an upper bainitic (ausferritic) microstructure. The investigation also examined the effect of cryogenic treatment on the fracture toughness of the material. Compact tension and cylindrical tensile specimens were prepared from ductile cast iron as per ASTM standards and were austempered in the upper bainitic temperature range of 371 °C to 400°C and were cryogenically processed. The mechanical properties and fracture toughness of these materials were evaluated and compared with non-cryogenically treated samples.