Papers by Russell Goodall
PLOS ONE
With the move away from fossil fuels, the importance of electric machines is increasing. This is ... more With the move away from fossil fuels, the importance of electric machines is increasing. This is particularly the case within major engineering sectors such as the automotive industry. There is therefore a need to further develop processes which will allow for the diverse range of machining operations and large volume manufacture which will be required to overcome the inherent challenges in making this transition. Several critical components of an electric machine, such as the rotor and the stator, are made from electrical grade steel. This is a steel where the composition and processing acts to optimise the magnetic and other properties for the application. The steel is processed as thin sheet laminations and then stacked, to reduce the losses which occur within it due to the generation of eddy currents. The laminations need to be cut to shape, in an operation currently carried out most frequently by stamping from a sheet, but which could be done with greater flexibility by laser c...
PLOS ONE
This paper proposes that laser cutting has potential as a viable alternative to stamping for mass... more This paper proposes that laser cutting has potential as a viable alternative to stamping for mass manufacture of thin steel components such as stator and rotor components in the electric automotive sector. Current laser cutting processes are much less efficient than stamping. However, laser cutting is much more flexible and is used for small batches and one-off production. This paper assesses the potential of performing laser cutting operations of multiple sheets or layers simultaneously. This method is referred to herein as polystromata cutting. A numerical model is used to assess the manufacturing performance of stamping, traditional laser cutting and polystromata laser cutting. Polystromata laser cutting is shown to be capable of producing parts at 37% less cost than stamping. However, polystromata remains slower than stamping, taking 79% more time to produce each stator stack. Through this research it has been identified that optimisation of polystromata processes is more comple...
Journal of Mechanical Engineering
Recently, carbon nanotubes (CNTs) reinforced metal matrix composites (MMCs) have attracted an inc... more Recently, carbon nanotubes (CNTs) reinforced metal matrix composites (MMCs) have attracted an increasing interest, due to their promising properties such as high Young’s modulus and tensile strength. CNTs are considered to be an attractive reinforcement material for lightweight and high-strength metallic matrix composites. When powder metallurgy (PM) is used to form these MMCs (such as Cu/CNTs composites), the sintering parameters are crucial in obtaining good final parts. This work attempts to investigate the effect of sintering parameters on physical properties in these MMCs. The process comprised of mixing of Cu powder with CNTs, compacting of the powder mixture to form green parts and sintering using a quartz tube furnace under argon atmosphere. In this study, four trials of heating rate were performed and evaluated before sintering process was conducted. Finally, the green body was initially heated isothermally at 100°C for 1 hour with heating rate of 1.0 °C/min and sintered at...
Journal of Materials Research and Technology
World Academy of Science, Engineering and Technology, International Journal of Materials and Metallurgical Engineering, 2017
Pure silver is used in conventional solar cells for front-side current collection as it exhibits ... more Pure silver is used in conventional solar cells for front-side current collection as it exhibits high conductivity, excellent solderability and good oxidation resistance. The long term cost of silver is expected to continue to rise therefore it is important to reduce silver content in solar cells. Previous attempts to use metal additives to reduce the quantity of pure silver required have resulted in alloys with poor resistivity and/or poor oxidation resistance. This study presents a collaborative research project to develop a lower cost alternative to pure silver using a novel developmental approach to selecting, producing and testing alloys of silver. Multivariable regression techniques were used to predict the properties of binary and tertiary silver alloy systems. Samples were converted to fine powders by gas atomisation and mixed with glass frits to produce pastes. Laboratory measurements of line and contact resistance were duplicated in a solar manufacturing line and screen printed cells produced. The consortium aims to produce an 18% efficient solar cell using an optimised alloy system.
MATEC Web of Conferences, 2021
This work focuses on the examination of two High Entropy Alloys (HEAs), the AlTiVCr and AlTiVCr–S... more This work focuses on the examination of two High Entropy Alloys (HEAs), the AlTiVCr and AlTiVCr–Si7.2, which have been observed to fail in a brittle manner directly after casting. Understanding the failure mechanics is a prerequisite for an alternative enhanced alloy design in order to prevent early failure without loading application. The specimens were produced using the Vacuum Arc Melting methodology in a protective argon atmosphere. The material was re–melted five times in combination with electromagnetic stirring in order to achieve a fully homogenized microstructure. Based on our findings, the failure occurred in the first 10 minutes after casting during slow cooling. Similarly, the same took place during thermal treatment after the third re–melting. The specimens were first prepared for optical (OM) and scanning electron microscopy (SEM) analysis. The material consists of a coarse dendritic microstructure as well as a retained BCC phase, which is the AlTiVCr phase. In the AlT...
Journal of Alloys and Compounds, 2021
According to a recent Hume-Rothery approach, the electron concentration, e/a, and the average rad... more According to a recent Hume-Rothery approach, the electron concentration, e/a, and the average radius can be used to identify the domain of stability of HEAs and to estimate the phases that may occur in the alloy. The present study investigates the influence of the electronic structure and the average radius on the hardness for a series of HEA alloys. The alloys investigated in this work all contained Co, Fe and Ni as base elements. To this base system one or more elements were added, including Al, Cr, Cu, Sn, Pd, Ru, Ti, and V in different proportions. For comparison, data on phases identified and hardness have been taken from a wide range of bibliography for other types of alloys in the systems Co-Cr-Fe-Cu-A-B-C-D-E-F, with A,
Journal of Alloys and Compounds, 2016
The structure of CoCrFe y Ni (y=0, 0.8 and 1.2) and CoCrFeNi-Pd x (x= 0.0, 0.5, 0.8, 1.0, 1.2 and... more The structure of CoCrFe y Ni (y=0, 0.8 and 1.2) and CoCrFeNi-Pd x (x= 0.0, 0.5, 0.8, 1.0, 1.2 and 1.5) High Entropy Alloys has been investigated by neutron and standard X-ray as well as by high-energy X-ray diffraction techniques. The alloys were produced by arc melting and afterwards heat treated under several different conditions. It has been concluded that the CoCrFeNi alloy in as-cast condition is, contrary to what is claimed in the literature, not singlephase but consists of at least two different phases, both of fcc type. The difference in lattice constant between the two phases is close to 0.001Å. Diffraction patterns measured by X-ray and neutron diffraction have shown that the structure of the alloy is not affected by 3 hours heat treatment up to 1100°C. Changing the amount of Fe has no drastic effect on alloy structure. The Pd-containing alloys have also all been found not to be single-phase but to consist of at least four different phases, all being of fcc type. The lattice constants for all phases increase with Pd content. The relative amounts of the different phases depend on Pd concentration. Furthermore, heat treatments of three hours duration at different temperatures have a significant effect on the alloy phase composition. It is suggested that HEAs should be considered as multicomponent alloys presenting "simple" diffraction patterns, e.g. consisting of one or several lattices of fcc, hcp or bcc type with very close lattice parameters.
Journal of Materials Processing Technology, 2017
The development of a replication casting device with the capability of manufacturing open-cell pu... more The development of a replication casting device with the capability of manufacturing open-cell pure Mg and Mg alloys foams, with melting points lower than 950 °C is described. The device consists of three basic parts: a cylindrical reaction chamber, a valve system for controlling the vacuum and the gas injection, and a heating system. The purpose of the present design was to improve the existing laboratory-scale devices, making them simpler than those reported in the literature, as well as to optimize the parameters (atmosphere, temperature, injection pressure, etc.) of the replication casting process. The proposed device has shown significant improvement over other devices reported, especially in terms of easiness of operation, adjustability and low cost of maintenance. The design of the device provides the ability to produce large foams free from defects such as large volumetric shrinkage and large concavities. The latter is minimized by the implementation of a perforated nozzle for gas impulsion. Examples of manufactured open-cell pure Mg and Mg-10 wt.% Al alloy foams are also presented. The design is shown in a conceptual format; however it could be modified to produce larger or smaller samples.
Materials
Nitinol (NiTi) alloys are gaining extensive attention due to their excellent mechanical, superela... more Nitinol (NiTi) alloys are gaining extensive attention due to their excellent mechanical, superelasticity, and biocompatibility properties. It is difficult to model the complex mechanical behavior of NiTi alloys due to the solid-state diffusionless phase transformations, and the differing elasticity and plasticity presenting from these two phases. In this work, an Auricchio finite element (FE) model was used to model the mechanical behavior of superelastic NiTi and was validated with experimental data from literature. A Representative Volume Element (RVE) was used to simulate the NiTi microstructure, and a microscale study was performed to understand how the evolution of martensite phase from austenite affects the response of the material upon loading. Laser Powder Bed Fusion (L-PBF) is an effective way to build complex NiTi components. Porosity being one of the major defects in Laser Powder Bed Fusion (L-PBF) processes, the model was used to correlate the macroscale effect of porosi...
Journal of Materials Science & Technology
Journal of Physics D: Applied Physics, 2021
The search for cheap, corrosion-resistant, thermally-mechanically stable functional magnetic mate... more The search for cheap, corrosion-resistant, thermally-mechanically stable functional magnetic materials, including soft magnetic and magneto-caloric materials has led to research focused on high entropy alloys (HEAs). Previous research shows that alloying elements with negative enthalpies of mixing can facilitate a second-order phase transition. On the other side of the spectrum, compositional segregation cause by positive enthalpy of mixing alloying additions (such as Cu) may also be used to tune magnetic properties. This paper studies the structural, magnetic and magneto-caloric effect of the FCC alloys CoFeNiCr y Cu x (x = 0.0, 0.5, 1.0 and 1.5, y = 0.0, 0.8 and 1.0) to tune these properties with Cu and Cr alloying. Scanning electron microscopy of the compositions show nanoparticles forming within the grains as the Cu concentration increases. Cr addition to CoFeNiCu1.0 has a larger effect on the magnetic and magneto-caloric properties compared to the Cu addition to CoFeNiCr1.0. Th...
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Papers by Russell Goodall