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- Synthesis of (Ti, W, Mo) CN based cermets with different carbides configurations for demanding applications: Study of the crystal structure, microstructure, and mechanical propertiesPublication . Rafiaei, Seyed Mahdi; Hadi, Morteza; Fernandes, F.; Fernandes, FilipeIn this study, based on different element configurations within constant atomic ratio of elements, (Ti0.93W0.07Mo0.07)C–20%Ni and (Ti0.93W0.07Mo0.07)CN0.3-20%Ni derived cermets have been synthesized. The basis for the difference in the production route was whether the carbides were formed by carbothermic reaction from the metal oxide together or separately, or in the case of Mo2C, the carbide is added to the mixture together with the binder after reduction and just before consolidation. Another basis for the difference was whether the cermet was a carbide or a carbonitride. To investigate the influence of the different production routes, the crystal structure, microstructure, and mechanical properties of the cermets produced were examined using XRD, FESEM, STEM, and Vickers indentation. The XRD spectra of all the cermets were found to be very similar to those of TiC-based cermets, indicating that the additive carbides in the TiC or Ti(CN) phases of the cermets dissolve perfectly during the high vacuum sintering process at 1510 °C. The highest toughness (14.65 MPa m1/2) was obtained in (Ti0.93W0.07) C–8%Mo2C–20Ni cermets with a core-rim structure. In addition, the use of nitrogen leads to a dramatic reduction in particle size. The use of molybdenum and tungsten in the form of separate carbides had little effect on limiting the expansion of crystal size and grain size compared to the scenario where the dissolution of these elements took place within the primary core-rim structure. However, in terms of hardness and toughness, it was found that, in addition to grain size, the route taken in the addition of molybdenum and tungsten was also important.
- Deciphering the mechanical strengthening mechanism: Soft metal doping in ceramic matrices: A case study of TiN-Ag filmsPublication . Luan, Jing; Kong, Fanlin; Xu, Junhua; Fernandes, Filipe; Evaristo, Manuel; Dong, Songtao; Cavaleiro, Albano; Ju, Hongbo; Fernandes, FilipeSoft metals have been widely added into ceramic-based films for fully meeting the demanding requirements of green tribological applications. However, the resulting considerable increase of the mechanical strength by adding a soft metal below 5 at.%, which reversed the rule-of-mixture, was still not fully revealed. In this paper, a case study of TiN-Ag films was carried out to investigate the strengthening mechanism induced by adding soft metal in TiN-Ag composite/multilayered films deposited by magnetron sputtering. The results showed that dual-phases of fcc-TiN and fcc-Ag co-existed in the composite films with the Ag particles embedded in the matrix. In some areas of the Ag particles, with a size below 4 nm, epitaxial growth with the TiN template was detected, which obliged the lattice to be distorted and shrunken. Consequently, both hardness and elastic modulus were enhanced from 21 and 236 GPa, for the reference TiN film, to 26 and 323 GPa for the TiN-Ag composite film with 2.4 at.% Ag. The possibility of having the epitaxial growth of Ag within TiN were also confirmed by designing a TiN/Ag multilayered film with an Ag layer thickness of ∼3 nm.
- Design and development of porous CoCrFeNiMn high entropy alloy Cantor alloy with outstanding electrochemical propertiesPublication . Abid, Talha; Akram, M. Aftab; Karim, M. Ramzan Abdul; Fernandes, Filipe; Fernandes, Filipe; Zafar, Muhammad Farooq; Yaqoob, KhurramCoCrFeNiMn high entropy alloys are among the most well-studied high entropy alloys that exhibit reasonable strength and outstanding ductility. In the present study, porous CoCrFeNiMn foams have been developed by the addition of copper in the base high entropy alloy by arc melting followed by its removal through an electrochemical dealloying process. Microstructure characterization of the as-cast samples confirmed limited solubility of copper in the matrix while the majority of the copper was found to segregate to interdendritic areas. Removal of copper from the interdendritic areas was successfully carried out by an electrochemical dealloying process which resulted in the development of foams with interconnected porosity. CoCrFeNiMn foams with different levels of porosities were successfully developed by varying the amount of added copper in the base HEA and its removal by a dealloying process. The electrochemical performance of the developed foams was assessed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). One of the developed foams was found to exhibit an areal capacitance of 1.56 F cm 2 at 2 mA cm 2 which is more than 2x times higher than the value reported for recently developed porous AlCoCrFeNi high entropy foam. Developed foam, besides showing excellent values of areal capacitance, demonstrated capacitance retention of 114.6% after 5000 cycles at 8 mA cm 2. The excellent electrochemical performance of the developed high entropy foams exhibits their potential to be used as electrode materials for supercapacitor applications and was attributed to the insertion of interconnected porosity in the base HEA.
- Influence of V concentration in TiAlSiVN coating on self-lubrication, friction and tool wear during two-pass dry turning of austenitic steel 316 LPublication . Kumar, Ch Sateesh; Urbikain, Gorka; Fernades, Filipe; Fernandes, Filipe; Rjoub, Abbas AL; Lacalle, Luis Norberto López deThe present work investigates the performance of TiAlSiVN coating with 5 and 11 at% of V concentration deposited on the Al2O3/SiC cutting tools during dry turning of austenitic 316 L stainless steel. The maximum flank wear reduction compared to the uncoated tool for coated tools with 11% and 5% V concentration was 85% and 67%, respectively. The Raman analysis indicated the formation of V2O5 in the cutting zone, which helps to reduce friction and machining forces for the coated tools. Overall, the presence of higher V content (11 at%) enhances the self-lubrication behaviour of the TiAlSiVN coating, accounting to lower fluctuations in cutting forces, superior surface finish, and lower flank wear when compared to the TiAlSiV5N coated and uncoated cutting tools.
- Microstructure evolution and mechanical behavior of magnetron sputtering AlN–Al nanostructured composite filmPublication . Ma, Bingyang; Sun, Boyuan; Li, Rongbin; Cao, Haoxin; Fernades, Filipe; Fernandes, FilipeIn this paper, a series of AlN–Al nanocomposite films are prepared by reactive magnetron sputtering. The effects of N2 flow rate on the microstructure and mechanical properties of the films are studied. The formation and evolution mechanism of the nanocomposite structure are revealed. The results show that with the decrease of N2 flow rate, the microstructure goes through three stages: pure AlN, amorphous Al surrounded nanocrystalline AlN and AlN nanoparticle reinforced Al matrix composite. Benefiting from the good wettability of Al on AlN ceramics, the film deposited at 6 sccm N2 flow rate forms a nanocomposite structure of about 8 nm AlN grains wrapped by 1–2 nm amorphous Al. The hardness of the films increases first and then decreases with the decrease of N2 flow rate, ranging from 4 GPa to 25 GPa. The toughness of the films is analyzed by the ratio of H/E, H3/E2, the normalized plastic depth (δH) and the morphology of large load indentation. The results show that the toughness of the nanocomposite film obtained at 6 sccm N2 flow rate is significantly improved while maintaining the hardness equivalent to that of pure AlN film. The improvement in toughness comes from the microcracks initiated in AlN hindered by the surrounding Al phase.
- Effect of V concentration in TiSiN monolayer coating on chip formation mechanism and chip sliding velocity during dry turning of Ti–6Al–4V alloyPublication . Kumar, Ch Sateesh; Urbikain, Gorka; Lucio, Pablo Fernández de; Pérez-Salinas, Cristian; Lacalle, Luis Norberto López de; Fernandes, Filipe; Fernandes, FilipeThe current study examines how the self-lubricating characteristics of the novel TiSiVN coating affect the chip formation process and chip sliding velocity during the dry turning of Ti6Al4V titanium alloy. The serration bands tend to straighten at a cutting speed of 125 m/min, which is the main cause of the chips being straightened without tangling for both coated tools. TiSiVN coated tool accounts for higher chip sliding velocity due to the generation of lubricious phases, whereas the higher VS for uncoated tool indicates high tool wear at the highest cutting speed of 125 m/min. Further, r and 0n tend to have an inverse relationship with VS, with 125 m/min cutting speed remaining an exception due to severe changes in tool wear dynamics. The reduction of friction helped to lower the localized strain along the shear bands and the effective stress at the beginning of the formation of the serrated tooth.
- Domestic Consumption Simulation and Management Using a Continuous Consumption Management and Optimization AlgorithmPublication . Gomes, Luis; Faria, Pedro; Fernandes, Filipe; Vale, Zita; Ramos, CarlosThe recent changes concerning the consumers’ active participation in the efficient management of load devices for one’s own interest and for the interest of the network operator, namely in the context of demand response, leads to the need for improved algorithms and tools. A continuous consumption optimization algorithm has been improved in order to better manage the shifted demand. It has been done in a simulation and user-interaction tool capable of being integrated in a multi-agent smart grid simulator already developed, and also capable of integrating several optimization algorithms to manage real and simulated loads. The case study of this paper enhances the advantages of the proposed algorithm and the benefits of using the developed simulation and user interaction tool.
- Combined heat and power and consumption optimization in a SCADA-based systemPublication . Fernandes, Filipe; Morais, H.; Faria, Pedro; Vale, Zita; Ramos, CarlosThe operation of power systems in a Smart Grid (SG) context brings new opportunities to consumers as active players, in order to fully reach the SG advantages. In this context, concepts as smart homes or smart buildings are promising approaches to perform the optimization of the consumption, while reducing the electricity costs. This paper proposes an intelligent methodology to support the consumption optimization of an industrial consumer, which has a Combined Heat and Power (CHP) facility. A SCADA (Supervisory Control and Data Acquisition) system developed by the authors is used to support the implementation of the proposed methodology. An optimization algorithm implemented in the system in order to perform the determination of the optimal consumption and CHP levels in each instant, according to the Demand Response (DR) opportunities. The paper includes a case study with several scenarios of consumption and heat demand in the context of a DR event which specifies a maximum demand level for the consumer.
- Intelligent management of end consumers loads including electric vehicles through a SCADA systemPublication . Fernandes, Filipe; Faria, Pedro; Vale, Zita; Morais, H.; Ramos, CarlosThe large penetration of intermittent resources, such as solar and wind generation, involves the use of storage systems in order to improve power system operation. Electric Vehicles (EVs) with gridable capability (V2G) can operate as a means for storing energy. This paper proposes an algorithm to be included in a SCADA (Supervisory Control and Data Acquisition) system, which performs an intelligent management of three types of consumers: domestic, commercial and industrial, that includes the joint management of loads and the charge/discharge of EVs batteries. The proposed methodology has been implemented in a SCADA system developed by the authors of this paper – the SCADA House Intelligent Management (SHIM). Any event in the system, such as a Demand Response (DR) event, triggers the use of an optimization algorithm that performs the optimal energy resources scheduling (including loads and EVs), taking into account the priorities of each load defined by the installation users. A case study considering a specific consumer with several loads and EVs is presented in this paper.
- Real-Time Simulation of Real-Time Pricing Demand Response to Meet Wind VariationsPublication . Gomes, Luis; Fernandes, Filipe; Faria, Pedro; Silva, Marco; Vale, Zita; Ramos, CarlosRecent changes of paradigm in power systems opened the opportunity to the active participation of new players. The small and medium players gain new opportunities while participating in demand response programs. This paper explores the optimal resources scheduling in two distinct levels. First, the network operator facing large wind power variations makes use of real time pricing to induce consumers to meet wind power variations. Then, at the consumer level, each load is managed according to the consumer preferences. The two-level resources schedule has been implemented in a real-time simulation platform, which uses hardware for consumer’ loads control. The illustrative example includes a situation of large lack of wind power and focuses on a consumer with 18 loads.