A nanoscale and pure, olivine-structured LiFePO4 was synthesized at ∼300 °C using an organic–inorganic steric entrapment method. Normally, when calcined and crystallized in air, this method leads to the synthesis of compounds where the cations are in their highest oxidation state. However, in this study, we found a way to produce compounds having lower oxidation states (e.g., compounds containing Fe2+), which may have wider applications in the synthesis of other compounds with complex chemistry that have variable oxidation states and, therefore, potential applications in electronic ceramics. The resulting LiFePO4 or (Li2O·2FeO·P2O5) was characterized by thermogravimetric analysis/differential thermal analysis, x-ray diffractometry, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma emission spectroscopy, specific surface area by Brunauer–Emmett–Teller nitrogen absorption, and particle size analysis.

The 〈001〉-textured 36Pb(In1/2Nb1/2)O3–30Pb(Mg1/3Nb2/3)O3–34PbTiO3 (36PIN–30PMN–34PT) ceramics were successfully prepared by the templated grain growth method using BaTiO3 (BT) templates with an average edge length of 10 μm and a thickness of about 0.5 μm. The highest Lotgering factor of 95% has been achieved for the textured ceramics with 5 wt% BT templates sintered at 1240 °C. The Curie temperature (TC) and dielectric constant (εr) of the textured 36PIN–30PMN–34PT ceramics were 225 °C and 2850, respectively. The piezoelectric constant d33 of the textured samples was 780 pC/N and almost 2 times higher than that of random 36PIN–30PMN–34PT samples. The planar mode electromechanical coupling coefficient kp was 59% for the textured samples. Unipolar strain-field measurements for the textured ceramics exhibited 0.34% strain at 4 kV/mm.

Fabrication of nanoperforated TiO2 thin films (NP-TiO2) on various substrates utilizing evaporation-induced self-assembly has been widely reported during recent years. For many applications, such as solar cells and gas sensors, it would be beneficial if the active material could be deposited onto a desired area or in the form of a pattern or array. In this study, inkjet printing was successfully used to produce NP-TiO2 at both ambient temperature and 60 °C. Especially for intermediate drop spacings (40 and 50 µm), millimeter-sized homogeneous NP-TiO2 patches were obtained with similar NP structure as those being processed by dip coating and drop casting. Compared to ambient temperature, inkjet printing at 60 °C provides a narrower height distribution of the NP structures of about 5 nm. Compared to dip coating and drop casting, inkjet printing enables the deposition of the ink onto target areas, thus enabling the fabrication of microscale arrays and other patterned structures.

A novel strain-rate jump method was developed for the plane-strain bulge test and used to investigate the time-dependent deformation behavior of gold thin films in the thickness range 100–400 nm. The experimental method is based on an abrupt variation of the pressurization rate. The evaluated strain-rate sensitivity was found to be five times higher for films in freestanding condition (m = 0.094) than for films tested on a SiNx substrate (m = 0.020). Bulge creep tests confirmed this increased time-dependence. The observation of the surface of the freestanding films after the creep tests provided evidence of apparent grain boundary sliding taking place next to intragranular plastic deformation. The out-of-plane deformation was presumably favored by the columnar microstructure of the samples, with grains extending between both free surfaces. In the case of SiNx-supported films, grain boundary sliding was prevented by the good adhesion of gold to the SiNx substrate.

Single-phase crystalline ZnSnP2 nanowires have been prepared via simple chemical vapor deposition method using powdered Zn and SnP3 as the precursors in a custom-built tube furnace reactor. The sublimed precursors were allowed to react with thermally evaporated Sn nanoparticles to yield ZnSnP2 nanowire films over areas of 40 mm2. The cumulative observations suggest that the Sn nanoparticles served both as the growth seed and main contributor of Sn. Prolonged growth time favored formation of Zn3P2 nanowires when the Sn supply was exhausted. For optimal growth conditions, surface and bulk elemental analyses showed homogenous elemental distribution of Zn, Sn, and P, with chemical composition close to 1:1:2 stoichiometry. Powder x-ray diffraction data and Raman scattering of the nanowire films along with single-nanowire analysis using high-resolution transmission electron microscopy indicated that the as-prepared ZnSnP2 nanowires possessed a sphalerite crystal structure, as opposed to the antisite defect-free chalcopyrite structure. Photoelectrochemical measurements in aqueous electrolyte showed that the as-prepared ZnSnP2 nanowires are capable of sustaining stable cathodic photoresponse under white light illumination. Overall, this study presented a benign and straightforward approach to prepare single-phase Zn-based phosphide nanowires suitable for energy conversion applications.

Shape-memory epoxy is receiving considerable attention because of its superior mechanical and thermal properties and excellent shape-memory performance. In this study, a novel series of shape-memory epoxy resins are prepared using hydro-epoxy, hexahydrophthalic anhydride, and diglycidyl 4,5-epoxy tetrahydro phthalate (TDE-85) to further improve the recovery force of shape-memory epoxy resins. The thermal, mechanical, and shape-memory properties of the shape-memory epoxy resin system are investigated by differential scanning calorimetry, dynamic mechanical analysis, bend test, and shape recovery test. Results indicate that the glass transition temperature (Tg), rubber modulus, and room-temperature bend strength increase as TDE-85 content increases. Investigation of the shape-memory behavior of the resin reveals that full recovery can be achieved after only several minutes when the temperature is equal to or above Tg. The shape recovery time decreases with the increase in TDE-85 content at Tg, Tg + 10 °C, and Tg + 20 °C. These results are attributed to the increase in TDE-85 content.

Phase maps of Co–Cr alloys bonded to dental porcelain cycled through an incremental number of porcelain firings at two separate thicknesses (0.5 and 1 mm) were analyzed. Bulk hexagonal close-packed (hcp) phase vol% of the alloy was found to increase with the number of porcelain firings for both 0.5 and 1 mm specimens. At the metal-porcelain interface, a uniform fine-grained hcp phase was observed. The depth and grain size of this hcp layer increased with the number of porcelain firings with the thicker specimens undergoing more substantial growth and transformation. Simple heat transfer modeling of the specimens during heat treatment cycles indicated that the thicker specimen had more time at high temperature to affect the face-centered cubic to hcp phase transformation. Therefore, the amount of porcelain firings and the thickness of the alloy should be considered and kept to a minimal when manufacturing metal-porcelain restoration.

Nanosized Al2O3 (Al2O3np) reinforced Al7075 composites were fabricated by specially made Al2O3np containing Mg powder and subtype multifrequency ultrasonic vibration. Compared to traditional techniques, Al2O3np was effectively dispersed in the matrix by the novel method. Microstructural studies showed that the addition of Al2O3np caused the grain refinement and that the resultant microstructures of composites depended on the dominant size and degree of Al2O3np clustering. The grain refinement could be mainly attributed to particle pushing mechanisms. Compared to the matrix alloy, the ultimate tensile and compressive strength of the as-cast composite with 1.5 wt% Al2O3np fabricated at 800 °C were increased by 59.6% and 42.6%, respectively. Transmission electron microscope analysis showed that high density dislocations and clear interfaces between particles and matrix were present in the grains, suggesting that the superior improvement of mechanical properties can be attributed to dislocation-type strengthening of matrix alloy and load transfer from matrix to hard nanoparticles.

The Oxide Dispersion Strengthened (ODS) materials are potential candidates as cladding tubes for Sodium-cooled Fast Reactors. The nano-oxides are finely dispersed within the grains and confer excellent mechanical properties to these alloys. Hence, assessing nano-particle stability under irradiation remains crucial to guarantee safe use of these materials. Although neutron irradiation remains a binding and challenging experimental study to conduct, difficulties can be overcome by ion beam processing. Ion beam processing of the ODS material allows to identify the radiation-induced Ostwald ripening as the mechanism governing the nano-particle response under irradiation. The result is the increase in size and a decrease in density of the finely dispersed Y2Ti2O7 nano-particles. Under neutron irradiation, radiation-induced Ostwald ripening appears to be less effective since a slight growth of nano-particles is observed. Further, our approach shows that nanoparticle growth kinetics should scale as φ1/3, φ being the radiation flux. This suggests that the low irradiation flux is at the origin of the slower growth kinetics of the neutron irradiated particles. Both neutron and ion irradiation induce a modification of the nanoparticles/matrix interfaces which are generally flat and sharp prior to irradiation and present steps after irradiation. This could alter the nano-particle coarsening during irradiation.

The mechanical response of materials under repeated impact loading is of primary importance to model different types of surface mechanical treatments, such as shot peening. A reverse identification method of stress–strain curves using repeated impact has been developed by Kermouche et al. [Kermouche et al., Mater. Sci. Eng., A569, 71–77 (2013)] and later improved by Al Baida et al. [Al Baida et al., Mech. Mater.86, 11–20 (2015)]. This study deals with the experimental validation of this method on three materials: a home-made pure iron, a commercially pure copper, and an industrial aluminum alloy. An approximate method derived from cone indentation theory to check the reverse method reliability. Balls of different sizes have been used to cover a wide enough range of strain. The results are also compared with macroscopic compression and traction tests. The effect of the strain rate on the stress–strain curve is discussed. The conclusion section highlights the rapidity and the ease of use of the reverse identification method.

Amorphous and nanocrystalline soft magnetic alloys have garnered interests in academia and industry due to their potentials for applications, such as power transformers, electric motors, and sensors. To achieve good glass formability, thermal stability, and prevent grain overgrowth, elements such as B, Nb, Ta, and Hf are used in many soft magnetic systems. However, the high price of these precursors results in expensive soft magnetic alloys. Herein, we report on substituting Ta and Hf with TaC and HfC, respectively, to significantly reduce the cost of Fe-based FINEMET and Co-based HTX005 alloys. Soft magnetic properties of these alloys are studied. The effect of thermal annealing and strain annealing on TaC and HfC substituted alloys are also investigated. Lastly, we discuss the cost analysis on these alloys. Using the synthesis route presented here, a cost reduction of up to 74% can be achieved.

Oxidation of atomized Al–Mg–Li alloys with compositions ranging from Al0.85Mg0.1Li0.05 to Al0.55Mg0.4Li0.05 (wt%) was examined by thermogravimetry/differential thermal analysis. The results showed that oxidation proceeded in two steps. During the first step, lithium and magnesium were oxidized preferentially and removed from the metallic phase. The other step, during which the remainder of the metallic phase was oxidized, occurred over a wide range of temperature (989–1098 °C). The temperature of the second effect decreased slightly with increasing magnesium content from 10 to 30% in the alloy. For Al0.55Mg0.4Li0.05 alloy, the second exothermic peak occurred at 540 °C, and no exothermic peak was observed at higher temperature. The porous structure formed during the selective oxidation promotes the oxidation of residual Al in the alloy. Al0.55Mg0.4Li0.05 was oxidized completely at 1100 °C, lower than the temperature of other alloys. The thermite reaction experiment of Al0.55Mg0.4Li0.05–Fe2O3 system conducted in Ar showed a reaction temperature of 587 °C, significantly lower than the reaction temperature observed for Al–Fe2O3 system.

The axial loading test was performed to investigate the effect of carburizing on crack initiation and growth behaviors of a gear steel under high cycle fatigue (HCF) and very high cycle fatigue (VHCF). As a result, the carburized gear steel exhibits the duplex S–N characteristics associated with different interior failure mechanisms. The failure process in the HCF regime can be described as inclusion → fisheye → final crack growth zone (FCGZ) → momentary fracture zone (MFZ), whereas that in the VHCF regime is described as inclusion → fine granular area (FGA) → fisheye → FCGZ → MFZ. Based on the definition of crack sizes at different transition stages and the evaluation of stress intensity factor, the models for predicting crack initiation and growth lives in the HCF regime and in the VHCF regime were established. The predicted crack initiation life tends to increase with the decrease of stress amplitude. In the VHCF regime, the crack initiation life associated with the FGA size is almost equivalent to the total fatigue life, whereas the crack growth life only occupies a tiny fraction. In view of the good agreement between the predicted and experimental results, the theoretical modeling method based on crack initiation and growth can be well used to predict the fatigue life of carburized steel with the interior inclusion-induced failure in the HCF regime and in the VHCF regime.

The present investigation aims to enhance the mechanical properties and shape memory characteristics of Cu–Ni–Al shape memory alloys (SMAs) by alloying additional elements. These additions were found to control the phase morphology and grain size, along with the formation of different volume fractions, sizes, and distributions of precipitates. The features of the precipitates were mainly dependent on the type of alloying element. It was found that a Co (1.14 wt%) alloy gave the best overall improvement in terms of the transformation temperatures, ductility, and shape memory recovery. These improvements were mainly due to the exceptionally high presence of the γ2 phase in the microstructures of the modified alloy. The results of the current investigation were analyzed and compared to those of previous studies related to Cu–Al–Ni SMAs.