| This research is on austempered ductile iron (ADI), which offers an excellent combination of low cost, design flexibility, good machinability, high strength-to-weight ratio, good toughness, good wear resistance and fatigue strength. While ADI has found quite wide application in some industries, its use in automotive parts production has been limited. ADI obtains its excellent properties through the development of a high carbon austenite+ferrite microstructure referred to as ausferrite. The properties of ADI can be tailored by changing the heat treatment schedule. In this research a special chemistry Ni-Mo-Cu ADI was subjected to heat treatment schedules. Mechanical properties (hardness, tensile strength, and toughness), tribological properties (scuffing and surface deformation) and microstructural studies were conducted. Feathery ausferrite microstructure produced by high austempering temperature and long time gave very good tribological properties. While martensitic microstructure produces by low austempering temperature and short time gave very high hardness. Heat treatment recommendations were made based on the targeted automotive applications. |
