The effect of carbon nanotube amount in machining of ZA-27 matrix carbon nanotube reinforced nano composite

Resumo

In recent years, the usage area of nano material reinforced composites has been increasing gradually. Accordingly, machining of metal matrix and nano material reinforced composite materials becomes important. In this study, the effect of carbon nanotube (CNT) on the machining of CNT-reinforced ZA-27 (zinc-aluminum) nano composite was investigated. For this purpose, 0.5%, 1.0%, 1.5%, 3.0% CNTreinforced ZA-27 based composites were produced by powder metallurgy method. Firstly, SEM images of composites were taken. Then, hardness measurements were made and pore amounts were determined. At the last stage, the machinability tests of nano composites have been carried out. Machinability tests were carried out by turning method to determine the cutting forces and surface roughness amounts. The tests were carried out with cemented carbide cutting tools under dry cutting conditions. Cutting speeds of 75, 125, 175, 225 m/min, feed values of 0.05, 0.10, 0.20 mm/rev and constant cutting depth of 1.0 mm were chosen as test parameters. The data obtained as a result of the tests were interpreted together with microstructure, porosity and hardness values. Hardness values decreased and the pore amounts increased with the increase in the CNT-reinforcement ratio within the composite structure.Cutting forces and the surface roughness amounts increased with the increase in feed value. Cutting forces and surface roughness amounts decreased together with increase in cutting speed. CNT-reinforcement material in the composite structure caused a decrease in cutting forces. However, surface roughness values showed an increase with the increase of CNTreinforcement ratio. It has been determined that CNT-reinforcement material facilitates machining by lubricating effect in dry machining conditions. Built-up edge (BUE) was observed on all cutting tool bits used in machining tests. BUE amounts increased in itself with the increase in CNT ratios and feed rates.

Keywords: Nano composite, Carbon nanotube, ZA-27, Machinability