The variant selection from the parent α phase to the product β phase during the enhanced phase transformation induced by the electric current pulses (ECPs) was investigated in a Cu–Zn alloy. The electron backscatter diffraction results showed that the crystallographic variant selection was not only across those prior α/α grain boundaries, but also within the α grain interior, and it implied that the nucleation of the β phase on the up-transformation obeyed a preferred orientation selection. Further analysis revealed that the orientation relationship between the α phase and the β phase variants nucleated from the α phase was close to 44.3° about <114>, which clearly described the rotation axes and the misorientation angles in terms of an axis/angle description when the high temperature phase nucleated from the matrix. Therefore, the ECP treatment would provide a new promising and convenient method to investigate the variant evolution on the up-transformation.

Morphological evolution and phase transformation of metastable intermediate precipitates are critical to their mechanical properties for the non-isothermal processing. During the non-isothermal precipitation, the formation of the new phases usually couples with structural evolution. Traditional structural characterization has limitation to resolve comprehensive changes simultaneously. In this study, we report direct observation, precipitation sequence, and the details of concurrent morphological and structural changes of various intermediate precipitates during non-isothermal heating in the Al–Cu systems with different pretreatments. The structural heterogeneity during the non-isothermal precipitation processes is resolved into coexistence of two different precipitate phases and quantitatively studied in terms of the phase transition and the morphological evolution. This paper presents the in situ small- and wide-angle synchrotron x-ray scattering (SAXS and WAXS) to refine and to identify the mixed structural information during multiple precipitation stages. The WAXS results show that the precipitation sequence is θ″ → (θ″ + θ′) → θ′ → (θ′ + θ) → θ upon heating. Due to the fact of the specifically oriented SAXS intensity, the evolution of the aforementioned phase transformation is resolved by the refinement of the SAXS intensity integrated over the selected area. These methods reveal multiscale information that is not trivial comparing to the traditional characterization methods.

The 8 mol% yttria-stabilized zirconia (8Y-ZrO2) was bonded to stainless steel 316L at 900 °C for 1 h in a protective Ar atmosphere using an interlayer of Ti/Ni/Ti. Interfacial microstructures were characterized using both secondary electron microscope (SEM) and transmission electron microscope (TEM), each with an attached energy dispersive spectroscope (EDS). A layer sequence of σ-phase/TiFe2/TiFe + β-Ti/Ti2Fe was observed at the stainless steel 316L/Ti interface, whereas a layer sequence of Ti2Ni/Ti2Ni + TiNi/TiNi3 was found at the Ti/Ni interface. Furthermore, TiO and c-ZrO2−x formed at the Ti/8Y-ZrO2 interface. An acicular α-Ti and a fine ω-phase existed along with β-Ti in the residual Ti foil adjacent to the stainless steel 316L, but α-Ti and Ti2Ni were observed within β-Ti in the other residual Ti foil adjacent to the 8Y-ZrO2. The orientation relationships of the ω-phase and β-Ti were ${\left[ {1\bar 10} \right]_{{\rm{ \beta {\hbox-} Ti}}}}//{\left[ {1\bar 210} \right]_{\rm{\omega }}}$ and ${\left( {111} \right)_{{\rm{\beta {\hbox-} Ti}}}}//{\left( {0001} \right)_{\rm{\omega }}}$, respectively. The microstructural development was elucidated with the aid of Fe–Ti and Ni–Ti binary phase diagrams.

A multistep heat treatment process consisting of intercritical tempering between quenching and conventional tempering contributed to the development of a ferrite–martensite dual-phase structure in a Ni- and Cu-containing high-strength low-alloy steel. By using electron backscatter diffraction and scanning transmission electron microscopy, the microstructures were found to have an elongated lathlike morphology with carbide and Cu precipitates located especially at the boundaries of ferrite and martensite crystals. Atom probe tomography reveals at atomic scale the existence of solute-diluted ferrite and solute-rich martensite, and the later phase was considered to be transformed from the reverse austenite that was formed during intercritical tempering. Cu precipitation greatly correlates with the microconstituents, resulting in different distributional characteristics of Cu precipitates within these two phases and at their boundaries. It is a promising process to utilize Cu precipitation strengthening and phase transformation toughening simultaneously in alloy steels.

We present a bottom-up fabrication route to fabricate solid-solution Rh–Pd–Pt ternary alloy nanoparticles (NPs), with well-controlled compositions through femtosecond laser irradiation of a mixed solution of metallic ions, without any reducing agents and complicated processes. The structure of fabricated NPs was crystalline, and formation of solid-solution alloy formation was confirmed by electron and x-ray diffraction measurements. The crystalline nature of alloy NPs was also confirmed through high-resolution transmission electron microscope measurement. According to energy dispersive spectroscopy analysis, elemental composition of an individual NP was almost the same as the initial feeding ratio of ions in the mixed solutions. The electronic state of the element in alloy NPs was confirmed to be pure metal by XPS measurement. The structural studies of Rh–Pd–Pt NPs suggested that the demonstrated technique opens up a new dimension for the fabrication of NPs, which has well-controlled properties for practical use in various fields.

To establish the relationships between composition, microstructure, and properties, the influence of Al addition on microstructure and properties of Cu–Fe-based coatings by laser induction hybrid rapid cladding was studied. With increasing Al content, the main diffraction peaks of ε-Cu phase are weakened but those of α-Fe phase are strengthened, the size of Fe-rich particles generally increases but the dendrite arm spacing is further reduced, and the number of Cu-rich grains precipitated inside the Fe-rich particles increases but the size reduces. Moreover, when the amount of Al is increased, the improvement in electrochemical resistance is attributed to large amounts of fine Cu-rich grains precipitated inside the Fe-rich particles, which results in large anode–small cathode effect. The microhardness also increases with Al content and the microhardness of Cu53.5Fe36Al10C0.5 coating is approximately 2.4 times higher than that of copper alloy substrate.

At room temperature (RT), Fe2Mo3O12 is stable in monoclinic structure phase and above 780 K it transforms to an orthorhombic phase. Experiment shows that in the high temperature orthorhombic phase, the material exhibits low or negative thermal expansion property. In the paper, new compounds with the formula Fe2–x(ZrMg)0.5xMo3O12 (x = 0–1.8) are reported. The compounds are designed and synthesized to reduce the phase transition temperature of the Fe2Mo3O12 by substitutional co-incorporation of Zr4+ and Mg2+ in it. It is found that the monoclinic-to-orthorhombic phase transition temperature can be lowered effectively by the co-incorporation. The orthorhombic phase of Fe0.4(ZrMg)0.8Mo3O12 may be obtained at RT and it may keep the orthorhombic structure as low as 103 K. Meanwhile, the co-incorporation of Zr4+ and Mg2+ may tailor the coefficient of thermal expansion (CTE) of the Fe2Mo3O12 and the near-zero CTEs are obtained for the compound around x = 1.7 (Fe0.3(ZrMg)0.85Mo3O12). This work paves the way toward developing low-cost and near-zero thermal expansion materials over wide temperature ranges.

Microwave irradiation has the potential to affect the mechanical properties of natural silks. We explored several tensile properties of Bombyx mori silkworm cocoon fibers (yield stress and strain, breaking stress and strain, Young's modulus, toughness) as a function of microwave exposure time; samples were stored in a desiccating environment prior to tensile testing. Microwave radiation did not significantly affect any of these properties. We conclude that silk can be incorporated as a reinforcing fiber—without significant deterioration in properties—into materials that are subjected to microwave processing and/or in-service microwave radiation. Microwave exposure decreased the Weibull modulus of fibers, indicating that fracture becomes less predictable as a result of the exposure. Since microwave exposure affects failure predictability but not the average breaking strength of fibers, silk is best suited for use in composite materials if microwave exposure is likely, so that load can be transferred from weaker to stronger fibers.

We have used phase-separated poly(3-hexyltiophene) (P3HT)/poly(L-lactic acid) (PLLA) blends to fabricate low-voltage ion-modulated transistors on a rough paper substrate. The semiconductor and insulator are mixed together in a solution and spin casted onto the paper substrate. Owing to their different solubilities and surface energies the P3HT and PLLA will phase separate vertically during the spinning process creating a thin layer of semiconductor on top of the insulator. This thin semiconductor layer, difficult to achieve by other means on an absorbing paper substrate, creates faster ion-modulated transistors. Using this approach we have created ring-oscillators on paper oscillating at 5 Hz.

In this article, we review focused ion beam serial sectioning microscopy paired with analytical techniques, such as electron backscatter diffraction or x-ray energy-dispersive spectrometry, to study materials chemistry and structure in three dimensions. These three-dimensional microanalytical approaches have been greatly extended due to advances in software for both microscope control and data interpretation. Samples imaged with these techniques reveal structural features of materials that can be quantitatively characterized with rich chemical and crystallographic detail. We review these technological advances and the application areas that are benefitting. We also consider the challenges that remain for data collection, data processing, and visualization, which collectively limit the scale of these investigations. Further, we discuss recent innovations in quantitative analyses and numerical modeling that are being applied to microstructures illuminated by these techniques.