This study aimed to evaluate the influence of steam blanching and the combination of citric acid dipping with blanching as pre-treatments on the vacuum drying of carrots. Carrot slices of two thicknesses, 2 mm and 5 mm, were subjected to varying periods of pre-treatments and citric acid concentrations of 0.5% (w/w) and 1.0% (w/w). The drying behavior, moisture loss, energy consumption, and other post-drying quality parameters, such as colour, water activity, rehydration ratio, tensile strength, and microstructure, were assessed. Pre-treatments enhanced moisture removal through osmotic dehydration and structural modification, resulting in improved drying efficiency by reduction of drying time, with maximum reductions of up to 34.78%, along with notable energy savings. Pre-treatments did not result in statistically significant differences (p < 0.05) in colour or tensile strength of the dried carrot samples. In addition to this, the rehydration ratio was found to be higher than that of the untreated samples. Further, all the dried samples were found to have lower water activity readings (<0.61). Scanning electron microscopy confirmed increased pore formation in pre-treated samples. The above results indicate that combined citric acid dipping followed by blanching enhances drying efficiency while preserving the quality of vacuum-dried carrots.
Calcium chloride (CaCl2) is a technologically important material used in applications ranging from desiccation and thermochemical energy storage to molten-salt electrochemistry. Most notably, it is used as the electrolyte in the FFC Cambridge process for metal/alloy production. Despite its widespread use at elevated temperatures, CaCl2 is often treated as a chemically and structurally invariant salt, with limited consideration of its solid-state history prior to melting. This review examines how hydration history, dehydration pathways, and associated microstructural evolution govern the thermodynamic stability and functional performance of CaCl2 across solid, liquid, and electrochemical regimes. The crystal chemistry of CaCl2 hydrates and their stepwise dehydration behavior are summarized, with emphasis on insights from in-situ high-temperature X-ray powder diffraction that reveal the coexistence of multiple hydrated, partially dehydrated, and anhydrous phases. Particular attention is given to the existence of distinct anhydrous CaCl2 polymorphs with different unit-cell volumes, their relative stability above 150 °C, and the role of lattice densification during dehydration. The limitations of conventional thermal analysis and the advantages of in-situ diffraction for resolving metastable intermediates and phase competition are critically discussed. Beyond the solid state, the review considers how pre-melting structural states, defects, and residual disorder may influence molten-salt structure, ionic transport, and electrochemical stability. The implications of these structure–stability relationships for molten-salt electrochemical processes are highlighted. Finally, key knowledge gaps and future research directions are identified, underscoring the need for integrated in-situ structural, thermal, and electrochemical studies to enable rational control of CaCl2 performance in high-temperature technology applications worldwide.
Bioinert materials for load-bearing orthopedic applications were fabricated using spark plasma sintering (SPS). The effects of the alumina (Al2O3) nanoparticle content and fabrication process conditions on the microstructure, density, hardness, dynamic tensile properties, and nanoindentation properties of Ti-12Ta-6Zr/xAl(2)O(3) bioinert materials were studied. Metallic Ti, Ta, and Zr powders were mechanically milled with 1, 2.5, or 5 % (w/w) Al2O3 nanoparticles as an oxide dispersed strengthening (ODS) reinforcement phase in the metal matrix. The milled powders with different compositions were consolidated using SPS at 1,273 K, followed by heat treatment at 1,473 K and water quenching. The powders and sintered materials were investigated using high-resolution scanning electron microscopy (HRSEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) to evaluate the particle size and shape, surface morphology, microstructure, chemical composition, and produced sample phase. Fully dense Ti-12Ta-6Zr/xAl(2)O(3) sintered materials were produced by SPS, and their mechanical properties were improved by subsequent heat treatment. In addition, the hardness and yield strength increased, while the elongation at break decreased, by increasing the Al2O3 nanoparticle content in the Ti-12Ta-6Zr metal matrix. The addition of up to 5 % (w/w) Al2O3 nanoparticles influenced density, hardness, and yield strength of the fabricated materials. The hardness and yield strength of the sintered materials by SPS improved after heat treatment. Increasing the Al2O3 particle content up to 5 % (w/w) increased the hardness from 324 HV to 540 HV (maximum) and the heat treatment process at 1,473 K improved the hardness of the Ti-12Ta-6Zr and Ti-12Ta-6Zr/5 % (w/w) Al2O3 to 448 and 593 HV, respectively. The yield strength is increased after heat treatment by increasing Al2O3 content from 448 MPa for Ti-12Ta-6Zr to 637 MPa for Ti-12Ta-6Zr/5 % (w/w) Al2O3. Also, the values of the elastic modulus estimated from the tensile stress-strain curves are increased from 24.9 GPa in case of Ti-12Ta-6Zr to 74.59 GPa in case of Ti-12Ta-6Zr/1 wt%Al2O3. The fracture surfaces of the sintered Ti-12Ta-6Zr/5 % (w/w) Al2O3 exhibits finer grain transgranular cleavage than Ti-12Ta-6Zr. The estimated modulus values extracted from the nano indentation measurements of the Ti-12Ta-6Zr (29.5 GPa) matched with the cortical bone. Our findings suggest that the produced Ti-12Ta-6Zr/xAl(2)O(3) biomaterials have great potential as new candidate materials for load-bearing orthopedic applications.
High-entropy alloys (HEAs) have emerged as one of the most transformative paradigms in modern materials design, offering exceptional combinations of mechanical strength, thermal stability, and corrosion resistance through configurational complexity. Within the expansive HEA landscape, low-melting-point (LMP) HEAs represent a strategically important subfield whose defining merit does not entirely rely on structural strength but on processing temperature. By accessing eutectic or near-eutectic melting in multicomponent systems, these alloys enable soldering, bonding, and interconnect applications at temperatures compatible with heat-sensitive substrates, flexible polymer platforms, biomedical implants, and cryogenic quantum devices. This review critically examines the compositional design space, processing routes, phase formation pathways, interfacial reaction behaviour, and emerging functional applications of LMP-HEAs, drawing systematically on a curated body of experimental literature published recently, as this area is quite new and has not received considerable attention so far. A central finding is that canonical single-phase solid-solution HEAs are exceptionally rare in low-melting chemistry space; instead, the field is defined by compositionally complex, entropy-rich multiphase systems where the cocktail effect rather than high configurational entropy itself is the dominant functional driver. Critical gaps in microstructural understanding, particularly regarding local phase partitioning, interfacial crystallography, and long-term aging stability, are identified and discussed. The review concludes with a comprehensive and forward-looking section on future research directions, including calculation of phase diagrams (CALPHAD)-guided alloy design, machine learning-assisted composition screening, advanced characterization, additive manufacturing integration, and commercialization pathways.
Abstract Bioinert materials for load-bearing orthopedic applications were fabricated using spark plasma sintering (SPS). The effects of the alumina (Al 2 O 3 ) nanoparticle content and fabrication process conditions on the microstructure, density, hardness, dynamic tensile properties, and nanoindentation properties of Ti–12Ta–6Zr/xAl 2 O 3 bioinert materials were studied. Metallic Ti, Ta, and Zr powders were mechanically milled with 1, 2.5, or 5 % (w/w) Al 2 O 3 nanoparticles as an oxide dispersed strengthening (ODS) reinforcement phase in the metal matrix. The milled powders with different compositions were consolidated using SPS at 1,273 K, followed by heat treatment at 1,473 K and water quenching. The powders and sintered materials were investigated using high-resolution scanning electron microscopy (HRSEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) to evaluate the particle size and shape, surface morphology, microstructure, chemical composition, and produced sample phase. Fully dense Ti–12Ta–6Zr/xAl 2 O 3 sintered materials were produced by SPS, and their mechanical properties were improved by subsequent heat treatment. In addition, the hardness and yield strength increased, while the elongation at break decreased, by increasing the Al 2 O 3 nanoparticle content in the Ti–12Ta–6Zr metal matrix. The addition of up to 5 % (w/w) Al 2 O 3 nanoparticles influenced density, hardness, and yield strength of the fabricated materials. The hardness and yield strength of the sintered materials by SPS improved after heat treatment. Increasing the Al 2 O 3 particle content up to 5 % (w/w) increased the hardness from 324 HV to 540 HV (maximum) and the heat treatment process at 1,473 K improved the hardness of the Ti–12Ta–6Zr and Ti–12Ta–6Zr/5 % (w/w) Al 2 O 3 to 448 and 593 HV, respectively. The yield strength is increased after heat treatment by increasing Al 2 O 3 content from 448 MPa for Ti–12Ta–6Zr to 637 MPa for Ti–12Ta–6Zr/5 % (w/w) Al 2 O 3 . Also, the values of the elastic modulus estimated from the tensile stress-strain curves are increased from 24.9 GPa in case of Ti–12Ta–6Zr to 74.59 GPa in case of Ti–12Ta–6Zr/1 wt%Al 2 O 3 . The fracture surfaces of the sintered Ti–12Ta–6Zr/5 % (w/w) Al 2 O 3 exhibits finer grain transgranular cleavage than Ti–12Ta–6Zr. The estimated modulus values extracted from the nano indentation measurements of the Ti–12Ta–6Zr (29.5 GPa) matched with the cortical bone. Our findings suggest that the produced Ti–12Ta–6Zr/xAl 2 O 3 biomaterials have great potential as new candidate materials for load-bearing orthopedic applications.
