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Electrical discharge coating of NiTi alloy in deionized water

2021-01-01 , Jamaluddin R. , Tan Chye Lih , Roshaliza Hamidon , Ahmad Fairuz Mansor , Azwan Iskandar Azmi

Shape memory alloys, specifically nickel-titanium (NiTi), exhibit excellent technical properties that suited them for biomedical applications. However, the release of nickel ions into human body is a drawback because it results in severe adverse health effects as well as degrades the biocompatibility of the alloys. In this work, surface modification through adaptation of electrical discharge machining was used to develop a deposition layer of titanium oxide on NiTi alloy surface. The adaptation was through electrical discharge coatings (EDC) parameters such as polarity, gap voltage, and erosion depth that were set up to study their effects on the experimental performance. The experiment was parameterized by implementing 2 level of full factorial design with ANOVA analysis to measure the surface roughness of that machined surface. One-factor-at-a-time, OFAT method is applied for XRD analysis by adopting the previous parameters approach. The EDC process was aided with deionized water and pure titanium rod as the dielectric fluids and electrodes, respectively. It was determined that the high level of gap voltage provided some major constituents on the surface of NiTi alloy based on XRD analysis. As apparent, this substantiated the presence of the tool materials and their oxide layer phases. The interaction of polarity and gap voltage also indicated a significant effect towards the surface roughness.

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Effects of machining conditions on the specific cutting energy of carbon fibre reinforced polymer composites

2017-10-29 , Azwan Iskandar Azmi , Syahmi A. , Naquib M. , Tan Chye Lih , Ahmad Fairuz Mansor , Khalil A.

This article presents an approach to evaluate the effects of different machining conditions on the specific cutting energy of carbon fibre reinforced polymer composites (CFRP). Although research works in the machinability of CFRP composites have been very substantial, the present literature rarely discussed the topic of energy consumption and the specific cutting energy. A series of turning experiments were carried out on two different CFRP composites in order to determine the power and specific energy constants and eventually evaluate their effects due to the changes in machining conditions. A good agreement between the power and material removal rate using a simple linear relationship. Further analyses revealed that a power law function is best to describe the effect of feed rate on the changes in the specific cutting energy. At lower feed rate, the specific cutting energy increases exponentially due to the nature of finishing operation, whereas at higher feed rate, the changes in specific cutting energy is minimal due to the nature of roughing operation.