Initial study of the microstructure of carbon fibres acting as negative electrodes in structural battery composites

Structural composite batteries are a novel type of multifunctional devices, which have a great potential to remarkably reduce the mass of electric vehicles, and thus increase their energy efficiency. In these batteries, carbon fibres (Carbon fibres) play dual roles: reinforcements (as in CARBON FIBRE composites) and negative electrodes (as in batteries). However, the relationship between the microstructure and the electrochemical property of the Carbon fibres is not well understood. In this study, the microstructure of two Carbon fibres, M60J and IMS65, were studied by using scanning electron microscopy and transmission electron microscopy. Detailed microstructural features were revealed, and correlated to the electrochemical properties of the Carbon fibres. The more disordered microstructure, and rather large pores are the reasons for the better electrochemical properties of IMS65 compared to M60J

Decision Support Systems

The current decision-making problems is more complex than it was in the past, prompting the need for decision support. Most real-world decision-making situations are subject to bounded rationality; whereby the technical and economic evaluation of all solution alternatives (branches) is bounded by the consideration of dominant subjective constraints. The early definition of DSS introduced it as a system that intended to support decision makers in semi-structured problems that could not be completely supported by algorithms. DSSs were planned to be an accessory for managers to expand their capabilities but not to replace them. Decision support systems could provide the means to complement decision makers by quantitatively supporting managerial decisions that could otherwise be based on personal intuition and experience. In addition to the traditional DSS characteristics (i.e., data and model orientation, interactivity), the inclusion of an intelligent knowledge base would be required to quantify the impacts of both technical (hard) and subjective (soft) constraints

Wolfram Syndrome presenting with optic atrophy and diabetes mellitus: two case reports

Wolfram syndrome is the constellation of juvenile onset diabetes mellitus and optic atrophy, known as DIDMOAD (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness)

Effect of the powder feedstock on the oxide dispersion strengthening of 316L stainless steel produced by laser powder bed fusion

In this study, the concept of enhancing the in-situ oxide precipitation in laser powder-bed fusion processed parts is investigated using powder produced by water and gas atomization. By using water-atomized 316L powder, compared to gas-atomized powder, more oxide precipitates were introduced into the microstructure with the intent to enhance the strength of the material, as an alternative path to oxide dispersion strengthened materials. The results showed that oxide precipitation was homogenous, with higher-number densities of oxides in the sample built using the water-atomized powder. The oxides were observed to be amorphous and enriched in Si and Cr. The average size of the oxides was ~56 nm. After an annealing heat-treatment at 900 \ub0C, the oxides were observed to remain within the microstructure with only minor changes in size and composition. Mechanical testing at room temperature and at elevated temperature did not show any increase in strength relative to the sample built using gas-atomized powder. However, it was shown that the use of water atomized powder in the L-PBF process provides a viable method of introducing and tailoring the number of oxide particles within a built component relative to a conventional gas atomized powder

Effect of atomization on surface oxide composition in 316L stainless steel powders for additive manufacturing

The initial oxide state of powder is essential to the robust additive manufacturing of metal components using powder bed fusion processes. However, the variation of the powder surface oxide composition as a function of the atomizing medium is not clear. This work summarizes a detailed surface characterization of three 316L powders, produced using water atomization (WA), vacuum melting inert gas atomization (VIGA), and nitrogen atomization (GA). X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy analyses were combined to characterize the surface state of the powders. The results showed that the surface oxides consisted of a thin (~4 nm) iron oxide (Fe2O3) layer with particulate oxide phases rich in Cr, Mn, and Si, with a varying composition. XPS analysis combined with depth‐profiling showed that the VIGA powder had the lowest surface coverage of particulate compounds, followed by the GA powder, whereas the WA powder had the largest fraction of particulate surface oxides. The composition of the oxides was evaluated based on the XPS analysis of the oxide standards. Effects of Ar sputtering on the peak positions of the oxide standards were evaluated with the aim of providing an accurate analysis of the oxide characteristics at different etch depths

On as-built microstructure and necessity of solution treatment in additively manufactured Inconel 939

Increased adoption of additively manufactured superalloys has led to the consideration of revised heat treatment approaches for these materials. The rapid cooling during additive manufacturing processes has been seen to suppress gamma prime (γ′) precipitation, which has raised the possibilities for omitting the high-temperature solution treatment step that usually precedes ageing heat treatment for these alloys. In this work, the as-built microstructure of a high gamma prime fraction superalloy Inconel 939 is presented, where the absence of any\ua0γ′ precipitation is notable. However, transmission electron microscopy shows the presence of nano-sized Eta (η) phase. It is shown that the omission of solution treatment leads to the growth of the deleterious\ua0η\ua0phase upon ageing, which results in embrittlement in tensile loading. It is concluded that at least for this particular alloy the solution treatment plays a critical role in the establishment of the required microstructure and hence cannot be omitted from the heat treatment

A new 12% chromium steel strengthened by Z-phase precipitates

In order to increase the corrosion resistance and simultaneously maintain the creep resistance of 9–12% Cr steels at 650 °C, a new alloy design concept was proposed, using thermodynamically stable Z-phase (CrTaN) precipi- tates to strengthen the steel. A new trial Z-phase strengthened 12% Cr steel was produced and creep tested. The steel exhibited good long-term creep resistance. Dense nano-sized Z-phase precipitates were formed at an early stage, and coarsened slowly. They remained small after more than 10,000 h