Phase identification is an arduous task during high-throughput processing experiments, which can be exacerbated by the need to reconcile results from multiple measurement techniques to form a holistic understanding of phase dynamics. Here, we demonstrate AutoPhase, a machine learning algorithm, which can identify the presence of the different phases in spectral and diffraction data. The algorithm uses training data to determine the characteristic features of each phase present and then uses these features to evaluate new spectral and diffraction data. AutoPhase was used to identify oxide phase growth during a high-throughput oxidation study of NiAl bond coats that used x-ray diffraction, Raman, and fluorescence spectroscopic techniques. The algorithm had a minimum overall accuracy of 88.9% for unprocessed data and 98.4% for postprocessed data. Although the features selected by AutoPhase for phase attribution were distinct from those of topical experts, these results show that AutoPhase can substantially increase the throughput high-throughput data analysis.

Cadmium sulfide (CdS) quantum dot (QD) nanoparticles have been synthesized using a one-pot noninjection reaction procedure in solvent medium 1-octadecene. This approach used a cadmium salt and 1-dodecanethiol, an organic sulfur, as the cadmium and sulfur sources, respectively, along with a long-chain organic acid (myristic acid, lauric acid, or stearic acid). The acid has dual effects as a surface capping ligand and a solubility controlling agent as well. UV–Vis and photoluminescence (PL) spectrometry techniques were used to characterize the optical properties, along with transmission electron microscopy (TEM) to identify the structure and size. Our newly developed synthesis procedure allowed for investigation of both regular and “magic-sized” CdS QDs by systematically controlling reaction parameters such as reactant type, reactant concentration, and reaction temperature. The organic sulfur (1-dodecanethiol) proved to be a useful sulfur source for synthesizing magic-sized CdS QDs, previously unreported. Several distinctive size regimes of magic-sized quantum dots (MSQDs), including Families 378 and 407, were successfully produced by controlling a small number of factors. The understanding of controlled Cd release in a MSQD formation mechanism is developed.

This study investigated influences of vacancy defects on buckling behaviors of open-tip carbon nanocones (CNCs) by molecular dynamics simulations. Effects of vacancy location and temperature on the buckling behaviors were examined in the study. Some interesting findings were attained from the investigations. It was noticed that the CNC with an upper vacancy has comparable degradation in the critical strain and in the critical load with the CNC with a middle vacancy, whereas the CNC with a lower vacancy has lower degradation in the antibuckling ability than the above two CNCs. The antibuckling ability of the CNCs reduces with the growth of the temperature. This temperature effect is more apparent in the perfect CNC than in the vacancy-defect CNCs. It was also observed that the degradation in the antibuckling ability is obvious at a lower temperature, but it decreases as the temperature grows. Besides, all the CNCs (including the perfect and the vacancy-defect CNCs) exhibited a shrinking/swelling buckling mode shape at the studied temperatures. Existence of the vacancies did not alter the buckling mode shape of the CNCs.

This study presents an analytical model of the reflectance of flat and textured silicon substrates. The model was used to study the reflection behavior of textured silicon surfaces under non-normal incidence. By characterizing the incident light and facets of the silicon wafer with vector geometry, dot products and Phong's reflection model (https://cs.oberlin.edu/∼bob/cs357.08/VectorGeometry/VectorGeometry.pdf) were used to determine the reflection angles between incident light rays and pyramidal facets. The possible optical interactions are considered for a wide range of pyramidal geometries and light incidence angles that are relevant to the exposure of textured silicon surfaces to incident sunlight. Furthermore, the model was used to investigate the possibility of secondary reflection, for the full range of incidence angles to the substrate. The textured silicon surfaces were found to reduce the reflection angles more effectively than flat substrates at lower angles of incidence. Secondary reflection was also found to be experienced or guaranteed, for all pyramid heights, when the angle of incidence to the substrate was less than 19.4°. The predictions are validated with experimental measurements of reflectance from (001)-textured silicon surfaces. The implications of the results are then discussed for the development of micropyramids for improved photoconversion in silicon solar cells.

LiFe1/3Mn1/3Co1/3PO4 (LFMC) has been synthesized by a microwave-assisted hydrothermal technique. During the crystal growth, two evolutionary routes coexist and compete with each other after the nuclei have been stably formed. One of them is the continuous growth of single particles and the other one is agglomeration. The size and morphology of the products are determined by the interplay of the two competing routes. The growth morphology is quantitatively analyzed from first principle calculations. A phase diagram is constructed, which guides to control the morphology by adjusting CM and pH. Static magnetic properties imply long range antiferromagnetic order below TN = 39 K and a paramagnetic Curie–Weiss-like behavior with θ = 75 K and peff = 5.51 μB at high temperatures. Cyclic voltammetry shows two distinct peaks corresponding to the Fe2+/Fe3+ and Co2+/Co3+ redox couples, respectively, whereas the Mn2+/Mn3+ redox couple is not observed due to its sluggish kinetics induced by the Jahn–Teller effect of Mn3+.

(CrTaTiVZr)Nx coatings were deposited via reactive radio frequency magnetron sputtering. The effects of N2 flow at 0–8 SCCM on the chemical composition, microstructure, and mechanical properties of the films were investigated. The coatings deposited at a N2 flow of ≤2 SCCM showed a featureless structure with an amorphous phase. When the N2 flow was at 4 SCCM, two distinct layers were observed, namely, the bottom layer (close to the substrate) with an amorphous structure and the top layer with a fibrous structure and face-centered cubic phase. When the N2 flow was further increased, the structure was converted from fibers to columns with larger grains. Accordingly, the maximum hardness value of 36.4 GPa was achieved at a N2 flow of 4 SCCM, thereby indicating that (CrTaTiVZr)Nx coatings may be suitable as hard protective coatings.

In this study, the authors have comparatively studied the influence of H2 addition on the structures and properties of ZnO films grown by metal organic (MO) chemical vapor deposition with dimethyl zinc and diethyl zinc as zinc precursors and N2O and O2 as oxygen sources, respectively. Various characterization methods, like x-ray diffraction, Raman scattering, Hall effect, photoluminescence, and atomic force microscopy, have been utilized, showing that H2 has different effects on different MO precursors and oxidants. The H2 addition has significantly improved the crystal structural quality of ZnO thin films for the case of dimethyl zinc source, but an opposite effect has been found for the case of diethyl zinc. Moreover, the H2 addition can significantly improve the optical properties of the ZnO films, regardless of the zinc MO sources used, with the surface morphology improved too. The suppression of carbon-related contaminations depends on the use of different precursors and whether H2 is added. By analyzing the experimental results, we have given the effects of H2 on the decomposition of the discussed MO precursors and oxidants, the proposed mechanism could be used in understanding the experimental data.

Many self-healing polymers require elevated temperatures for healing. Curie temperature (TC) controlled magnetic nanoparticles can generate heat through the application of an external alternating magnetic field (AMF). Thus, heating can be localized and regulated, preventing damage to the polymer due to high temperatures. In this work, novel TC controlled magnetic nanoparticle filler–polymer matrix composites (Magpol) were investigated as wire insulation materials. Mn–Zn ferrites were introduced as the filler in a thermoplastic polyethylene vinyl acetate (EVA) matrix. The composite was subjected to different damage modes, such as chaffing and tear. Greater healing efficiency was obtained at lower filler loading compared to other relevant systems. Efficient healing was obtained without any thermal degradation. Good agreement was observed between experimental results and theoretical models of polymer healing. Thus, a Curie temperature controlled magnetic nanocomposite system was developed with improved self-healing capabilities.

The thermal conductivities of epoxy composites of mixtures of graphite and graphene in varying ratios were measured. Thermal characterization results showed unexpectedly high conductivities at a certain ratio filler ratio. This phenomenon was exhibited by samples with three different overall filler concentrations (graphene + graphite) of 7, 14, and 35 wt%. The highest thermal conductivity of 42.4 ± 4.8 W/m K (nearly 250 times the thermal conductivity of pristine epoxy) was seen for a sample with 30 wt% graphite and 5 wt% graphene when characterized using the dual-mode heat flow meter technique. This significant improvement in thermal conductivity can be attributed to the lowering of overall thermal interface resistance due to small amounts of nanofillers (graphene) improving the thermal contact between the primary microfillers (graphite). The synergistic effect of this hybrid filler system is lost at higher loadings of the graphene relative to graphite. Graphite and graphene mixed in the ratio of 6:1 yielded the highest thermal conductivities at three different filler loadings.

Ti was added to Mg–Ni alloy (Mg95Ni5) by a novel hydriding combustion synthesis (HCS) process. The effect of Ti on hydrogen absorption/desorption kinetics of Mg95Ni5 was investigated. The results showed that Ti had superior catalytic effects on hydrogen storage properties of Mg95Ni5, which required only 80 s to reach its saturated hydrogen absorption capacity of 6.29 wt% at 473 K and released 5.49 wt% hydrogen within 900 s at 553 K. Based on an Arrhenius analysis, the activation energy of the hydrogen desorption process was 80.8 kJ mol−1 for the main phase of MgH2 in the Ti-doped Mg95Ni5. The excellent hydriding/dehydriding properties were related to the existence of TiH1.924, which improved the efficiency of mechanical milling and was helpful in the refinement of the crystallite size of MgH2, resulting in more fresh surface area and grain boundary area. Besides, it was thought to restrain the Mg particles from growth during the hydrogenation/dehydrogenation cycles.

Crystalline Au nanoparticles embedded in epitaxially grown SrTiO3 layers were prepared by an annealing and coating procedure of Au seed layers on SrTiO3 (STO) substrates. X-ray diffraction and transmission electron microscopy measurements were performed to investigate the size, shape, and deformation of the particles and their crystal orientation. The shape and size of the crystalline Au nanoparticles can be tuned by controlling the Au seed layer thickness and single crystalline elliptically shaped Au nanoparticles have been generated. Furthermore, the orientation of the surrounding SrTiO3 matrix changes significantly from homoepitaxially grown (001) to secondary (111) and (011) orientations for Au seed layers that are thicker than 4 nm. This is of great interest for modifying the electrical properties of SrTiO3 layers, whereas the anisotropically shaped crystalline particles are relevant for optical applications, due to localized surface plasmon resonances.

The mechanical properties of ultrafine-grained aluminum produced by equal-channel angular pressing (ECAP) are strongly influenced by strain rate. In this work, an experimental investigation of local strain rate sensitivity as it relates to microstructure was performed using a combination of scanning electron microscopy and digital image correlation. Uniaxial tension tests were carried out at 200 °C and strain rates alternating between 2.5 × 10−5 s−1 and 3.0 × 10−3 s−1. The results demonstrate that the heterogeneous microstructure generated by ECAP has a strong effect on the microstructure scale strain rate sensitivity. Deformation centered at grain boundaries separating regions of banded microstructure exhibits the greatest strain rate sensitivity. Strain rate sensitivity is limited in deformation occurring in regions of microstructure composed of ultrafine grains separated by low-angle grain boundaries. The tensile specimens all failed by shear bands at 200 °C and at room temperature they failed by necking with little plastic deformation apparent outside of the neck.

With the increasing usage of Al alloys in vehicle manufacture, it is necessary to join dissimilar Al alloys with lap joint. However, hot cracking is a challenging issue due to the chemical composition and thermal tension, which greatly determines the reliability of automobile operation. Among different Al alloys, the series 5000 (Al–Mg) and 6000 (Al–Mg–Si) are widely used. To better understand the hot cracking behavior, various stack ups of AA5754 and AA6013 were laser welded to investigate the effects of process parameters on hot cracking formation. The chemical composition, microstructure, fusion ratio, and fracture morphology of the weld joint were also examined. The results showed that the order of material stacking affected weld's susceptibility to hot cracking significantly, and the critical process parameters were obtained for tested conditions which could effectively reduce hot cracking. The findings from this work provide guidance for hot cracking prevention in laser welding of dissimilar Al alloys.

The influences of parameters on the bubble size in aluminum alloy melt during the gas injection foaming process were studied. The four parameters were the orifice diameter (0.4–3.0 mm), the orifice numbers (1 and 4), the gas chamber volume (11–800 cm3), and the gas flux (10–282 L/h). It was found that the bubble size decreased with the decrease of the orifice diameter and the gas chamber volume, and with the increase of the orifice number. The effect of gas flux showed a dual-stage at different gas fluxes: the “metastable large bubble stage” and the “stable bubbling stage”. A modified semiempirical formula and a concept of “effective gas chamber volume,” which is the nominal chamber volume divided by the effective orifice number, were proposed. The bubble size calculated by the modified formula with the effective gas chamber volume agreed well with the experimental data.

The present research is focused on studying the evolution of microstructure and texture of a magnesium based alloy with the target composition Mg–3Al–1Zn–(0.5AgIn). Three samples A, B, and C were warm rolled at 300 °C to a cumulative reduction of 33% in 1, 2, and 8 passes, respectively. The optical microstructures and scanning electron microscopy (SEM) results revealed that sample A possessed more dynamic recrystallization (DRX) as compared to samples B and C. A split of basal pole from normal direction (ND) toward transverse direction (TD) was observed for sample A. However, as the number of passes was increased, the basal pole split was converted into a single peak for samples B and C. The basal intensity of sample C became almost double than that of sample A. It was concluded that a higher reduction per pass resulted in a larger volume fraction of DRXed grains and a weaker basal texture.

The Mn-steel matrix composite locally reinforced with in situ TiC–TiB2 ceramic particulate was successfully fabricated using a thermal explosion-casting route in a Cu–Ti–B4C system with various B4C particle sizes. With the increase of B4C particle size, the ignition temperature increased, the combustion temperature decreased, and the size of the TiC and TiB2 ceramic particulates became smaller. The hardness, friction coefficient, and wear resistance of the composite were higher than those of the Mn-steel matrix. With the increase of B4C particle size, the size of the TiC and TiB2 ceramic particulates fabricated in the local reinforcing region decreased, the interface bonding between reinforcing region and matrix became poor, and the number of pores in the local reinforcing region increased. Moreover, the composite with ∼3.5 μm B4C showed the best antiwear property. At a low load of 20 N, the dominant wear mechanisms of the Mn-steel matrix composite were microcutting and abrasive wear. While, at a high load of 80 N, the dominant wear mechanisms were microcutting and adhesion wear associated with the formation of delamination layer.

The dynamic recrystallization (DRX) behavior of Ni–18.3Cr–6.4Co–5.9W–4Mo–2.19Al–1.16Ti superalloy was investigated by means of isothermal compression tests in the temperature range of 1010–1160 °C and strain rate range of 0.001–1 s−1. It was found that the nucleation mechanisms of discontinuous DRX and continuous DRX (CDRX) occurred simultaneously during hot deformation, and twinning can play an important role in improving the process of DRX. There are three stages in the process of CDRX, i.e., the accumulation and rearrangement of dislocations, the formation of subgrain boundary, and the conversion to high angle grain boundaries (HAGBs) from subgrain boundary. Moreover, the effect of CDRX grows weaker with increasing deformation temperature and decreasing strain rate. Additionally, both the volume fraction of DRX grains and the DRX grain size were closely related to the deformation temperature and strain rate, and a power exponent relationship between the DRX grain size and Z parameter was obtained. Based on the experimental data, the kinetic equations were also developed to evaluate the volume fraction of DRX grains during hot deformation in the alloy.