Search

• Fe addition improves the YS and UTS of studied alloys. • Fe addition change the morphology of Fe-rich particles from Chinese-script to interconnected structure;. • Fe-rich particles block the movement of dislocation;. • Neutron diffraction showing higher dislocation density in the 0.8Fe alloy. This paper examines the effect of Fe addition on the microstructure characterized by scanning electron microscopy/electron backscattered diffraction, neutron diffraction, and synchrotron X-ray tomography and the mechanical properties of Al-Mg-Mn-Fe-Cu alloys. The findings reveal that the microstructures of the alloys consisted of an Al matrix, Al 6 (FeMn), and Al 2 CuMg phase particles. The addition of Fe significantly increased the yield strength (YS), and ultimate tensile strength (UTS) of the alloys, while reducing elongation. The transformation of the 3D morphology of the Al 6 (FeMn) phase from separated and fine particles with Chinese-script morphology to interconnected rod-like structure as Fe content increased from 0.1 % to 0.8 %. This strengthening effect was attributed to the slip lines being blocked at the vicinity of the interconnected Fe-rich phase, leading to grain rotation and dislocation density increment around the Fe-rich phase, ultimately improving the strength of the alloys. However, the Fe-rich phases and Al 2 CuMg phases were found to be prone to cracking under tensile stress, resulting in decreased elongation of the alloys. This study provides a potential application in the design and manufacturing of new non-heat-treatable Al alloys for the automotive industry. [Display omitted] [ABSTRACT FROM AUTHOR]

• The horizontal oscillation of droplets at the S/L front during the solidifications of Al-3.2 wt.% Bi alloy was firstly in situ observed. • Real-time force analysis on droplets was conducted with time-evolved thermal-solutal experimental results. • The effect of solutal Marangoni force and lift force caused by flow was estimated to be non-negligible on the motion of the droplet. • Force balance of droplet both vertically and horizontally can possibly be obtained considering a lift force of 6.39 × 10−9 N and a modified solute-related parameter d σ d c of 0.45–0.65 J m−2. During solidifications of immiscible alloys, the motion of droplets at the solid/liquid (S/L) interface is generally driven by dragging force, gravity force, repulsion force of interface, and thermal-solutal Marangoni force. However, there is few in situ study investigating kinetics behavior to analyze the forces on droplets. The mechanism of droplet motion remains unclear due to the unavailability or uncertainty of the effect of convection and solutal Marangoni force on droplet behavior. In this study, directional solidification of immiscible Al-Bi alloy was observed via synchrotron radiography, and the horizontal oscillation of droplets at S/L interface was detected for the first time. Forces, especially solutal Marangoni force, were calculated based on the in situ measured radius of droplets and thermal-solutal gradients. The experimental results cannot be reasonably explained by the previous analysis model which neglects melt convection. The non-negligible effect of flow on droplet motion was demonstrated, and the force balance of droplet both vertically and horizontally can be obtained considering a lift force of 6.39 × 10−9 N and a modified solute-related parameter d σ d c of 0.45−0.65 J m−2, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

The use of X-ray phase-contrast microtomography for the investigation of Chinese medicinal materials is advantageous for its nondestructive, in situ, and three-dimensional quantitative imaging properties.

Drug delivery systems (DDSs) play an important role in delivering active pharmaceutical ingredients (APIs) to targeted sites with a predesigned release pattern. The chemical and biological properties of APIs and excipients have been extensively studied for their contribution to DDS quality and effectiveness; however, the structural characteristics of DDSs have not been adequately explored. Structure pharmaceutics involves the study of the structure of DDSs, especially the three-dimensional (3D) structures, and its interaction with the physiological and pathological structure of organisms, possibly influencing their release kinetics and targeting abilities. A systematic overview of the structures of a variety of dosage forms, such as tablets, granules, pellets, microspheres, powders, and nanoparticles, is presented. Moreover, the influence of structures on the release and targeting capability of DDSs has also been discussed, especially the in vitroand in vivorelease correlation and the structure-based organ- and tumor-targeting capabilities of particles with different structures. Additionally, an in-depth discussion is provided regarding the application of structural strategies in the DDSs design and evaluation. Furthermore, some of the most frequently used characterization techniques in structure pharmaceutics are briefly described along with their potential future applications.

Full-field x ray nano-imaging (FXNI) is one of the most powerful tools for in-situ, non-destructive observation of the inner structure of samples at the nanoscale. Owing to the high flux density of the third-generation synchrotron radiation facility, great progress is achieved for FXNI and its applications. Up to now, a spatial resolution of 20 nm for FXNI is achieved. Based on the user operation experiences over the years at the Shanghai Synchrotron Radiation Facility (SSRF) x ray imaging beamline, we know lots of user experiments will rely on a large range of spatial resolutions and fields of view (FOVs). In particular, x ray microscopes with a large FOV and a moderate spatial resolution of around 100 nm have a wide range of applications in many research fields. Driven by user requirements, a dedicated FXNI system is designed and constructed at the SSRF. This microscope is based on a beam shaper and a zone plate, with the optimized working energy range set to 8–10 keV. The experimental test results by a Siemens star pattern demonstrate that a spatial resolution of 100 nm is achieved, while an FOV of 50 μm is obtained.