The isothermal heat treatment process has been identified as a unique process of fabricating exceptional graphite cast iron due to its remarkable mechanical properties, such as excellent machinability, toughness, and high level of ultimate tensile strength. Austempered ductile iron (ADI), ductile iron (DI), and gray cast iron (GCI), known as spheroidal cast irons, are viable alternative materials compared to traditional steel casting, as well as aluminum casting. The graphite nodules from the microstructures of DI, ADI, and GCI are consistently encompassed by acicular ferrite and carbon-saturated austenite in the matrix, forming a distinctive ausferritic structure. All these materials are extensively used in the fabrication of engine sleeves, engine blocks, valves, gears, and camshafts in the automobile sector. With relative motion and outward loads, these components are regularly exposed to surface contact. In this project, it was observed that austempering temperature and a shorter holding period could also be used to manufacture needle-like ferrite platelets for austempered ductile iron (ADI) and other graphite cast irons. To overcome the brittleness challenges and catastrophic failures encountered by applied loads in present-day applications, it is essential to comprehend the isothermal treatments, morphological behaviors, phase analyses, processing techniques, and mechanical properties needed to properly incorporate these materials into future designs. This review article provides detailed information on the characterization and relevant potential mechanisms of ADI, DI, and GCI.

This work focused on the mechanical and corrosion behaviors of electroplated nickel on heat-treated low carbon steel serving as an alternative to austenitic stainless steel for the yam beater in a yam pounding machine. Four standard samples were prepared for electrodeposition from the steel samples by heating to a temperature of 920∘C with a 60-min holding time. One of the samples was air-cooled while the remaining three were quenched in H2O and later tempered at 450∘C, 550∘C and 650∘C for 60[Formula: see text]min. After the heat treatment process, the ultimate tensile strength, toughness, and microhardness of the samples were obtained. Nickel electrodeposition was later carried out on the heat-treated mild steel using Watt standard bath concentration. Optical Microscopy (OM) and Scanning Electron Microscope equipped with energy dispersion spectroscopy (SEM/EDS) were used for the characterization of the heat-treated and nickel-electrodeposited samples. More so, the electrochemical behavior of the nickel-plated samples was studied in a yam fluid environment using the potentiodynamic polarization technique. X-ray fluorescence (XRF) was used to analyze the chemical and oxide composition of the samples. The results showed that among all the heat treatment operations, the sample heat-treated at 920∘C and tempered at the highest tempering temperature of 650∘C gave the highest toughness value (102[Formula: see text]MJ/m3) when compared with stainless steel at 124[Formula: see text]MJ/m3. The sample heat-treated at 920∘C and tempered at 550∘C displayed a corrosion rate of 0.022182[Formula: see text]mm/yr as against the stainless steel sample with a value of 0.0031864[Formula: see text]mm/yr. From the analysis, the nickel deposited on the heat-treated samples enhanced corrosion resistance in the yam fluid. XRF analysis of the yam before pounding, after processing with nickel electroplated, and stainless beaters shows the content of nickel as 0.0941%, 0.109%, and 0.1113%, respectively. It was concluded that the materials for the yam pounding beater, therefore, perform better if they were both heat-treated and nickel-plated. Invariably, stainless steel could be successfully replaced with heat-treated and nickel-plated mild steel for use as a yam pounding beater.