Research was carried out to develop a mathematical model based on the cutting tool surface profile geometry to predict surface roughness in face milling. Previous models were derived using either the simple assumption of a perfectly round tool nose or statistical analysis based on a large number of experiments. In this research, three milling cases were defined based on the magnitude of the feed rate using a triangular insert with a round corner. In case 1, the machine marks only consisted of a series of arcs. In case 2, the machine marks included a series of an arc and one straight line. In case 3, the machine marks consisted of a series of an arc and two straight lines. Three different equations for surface roughness prediction were obtained based on each of the three cases. Experiments were done to validate the models, and the results showed that the mathematical models had good correlation with experimental results.

With the rapid growth in the use of electronics, more studies are focusing on the tribological performance of electrical connectors. The most common electroplating coating materials are tin and copper. One major issue is when fretting corrosion produces metal oxides, which are likely to increase the electrical resistance at the contact interface. This research aims to reduce metal oxidation of electrical connectors by studying the tribological performance of various thicknesses of tin and copper layers with a designated electrical circuit to be used with a reciprocating wear test. This research considers the effect of tin and copper layer thickness, including the lack of a tin layer, on the tribological behavior. Among coatings tested, a thin coating of copper with no tin resulted in the least wear. A thicker coating of copper significantly increased the wear due to the high roughness of the sample with a thick copper coating. Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) results indicated that adhesive wear occurred during sliding. Adhered particles led to two-body abrasive wear and when the adhered particles break away three-body abrasive wear is produced.

Austempered gray iron (AGI) with its unique ausferrite microstructure is an alternative material to traditional quenched and tempered gray iron with martensite microstructure due to its excellent mechanical properties. This research studies the process of ausferrite formation and kinetic characterization for gray cast iron. Specimens were austenitized at 832°C (1530°F) for 20 min and then held at different isothermal temperatures from 232°C (450°F) to 427°C (800°F) and isothermal times from 20 s to 120 min. The experimental results were analyzed using hardness tests and optical microscopy. Needle-like ausferrite structure was found while using austempering temperatures ranging from 232°C (450°F) to 371°C (700°F). The ferrite plates became coarse with increasing austempering temperature. Feather-like ausferrite was obtained at the austempering temperatures of 399°C (750°F) and 427°C (800°F). Transformation kinetics was utilized to analyze the ausferrite formation, and the activation energy of gray cast iron was found to be 39905.27 (J/mol) with a frequency factor of 6.06457 (1/s).