Phase Morphology Research Articles

The effect of polycaprolactone polyol molecular weight and chain extender type on the physico-mechanical properties and gas permeability of polyurethane thermoplastic elastomer membranes

ABSTRACT In this study, polyurethane thermoplastic elastomers (TPU) were synthesized using isophorone diisocyanate (IPDI), 1,4-butanediol (BDO), and 1,6-hexanediol (HDO) as the chain extenders, and polycaprolactone diol (PCL-diol) with three different molecular weights (2000, 4000, and 10,000 g/mol) as polyols. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) patterns, and differential scanning calorimetry (DSC) were conducted to analyze the chemical microstructure and phase morphology of the prepared samples. The results showed that the change in the chain extender’s type (BDO and HDO) leads to a decrease in the hydrogen bonding index (HBI). Increasing the molecular weight of PCL-diol in BDO-based TPUs has led to an increase in their crystallinity, Young’s modulus, melting temperature, tensile strength, and a decrease in glass transition temperature and elongation at break. Moreover, the increase in the molecular weight of PCL-diol in HDO-based TPUs demonstrated an increase in the crystallinity and elongation at break and tensile strength up to the molecular weight 4000 in PCL-diol, after that, there was a decrease in those properties due to the increase of the soft segments content and change in the chain extender type. Permeability on TPU membranes was performed for N2 and CO2 at three different pressures 3, 6, and 9 atm at room temperature. An increase in pressure led to an increase in membrane permeability due to the increase in gas solubility in TPU based on Henry’s law. The permeability of CO2 is higher than N2 due to the proper interactions of CO2 gas with the polar carbonyl groups of polyurethane. It is observed that the permeability increases in BDO-based samples with an increase in the molecular weight of PCL-diol, while the increase in permeability of HDO-based TPU is up to PCL-diol molecular weight 4000 and after that is decreased. The selectivity of CO2 has decreased with increasing pressure due to the higher rate of dissolution of N2 at higher pressures.

Phase Morphology Dependence of Ionic Conductivity and Oxidative Stability in Fluorinated Ether Solid-State Electrolytes

Phase Morphology Dependence of Ionic Conductivity and Oxidative Stability in Fluorinated Ether Solid-State Electrolytes

Interface Nuclei in the Y-Ag-Zn System: Three Chemical Pressure-Templated Phases with Lamellar Mg2Zn11- and CaPd5+x-Type Domains.

The interface nucleus approach was recently presented as a framework for understanding and predicting the emergence of modular intermetallic phases, i.e., complex structures derived from the assembly of units from simpler parent structures. Here, we present the synthesis and crystal structures of three new modular intermetallics in the Y-Ag-Zn system that support this strategy: YAg2.79Zn2.80 (I), YAg2.44Zn3.17 (II), and YAg2.71Zn2.71 (III). Each of these structures is derived from an intergrowth of slabs of the Mg2Zn11 and CaPd5+x types, with the chief differences being in the thickness and degree of disorder within the CaPd5+x-type domains. The merging of the parent structure domains is facilitated by their sharing a common geometrical unit, a double hexagonal antiprism. The use of this motif as an interface nucleus mirrors its role in another family of structures: an intergrowth series combining the CaCu5 and Laves phase structure types, as in the PuNi3-type phase YNi3. However, there is a key difference between the two series. While in the CaCu5/Laves intergrowths, the interface between the parent structures arises perpendicular to the interface nucleus's unique (hexagonal) axis, in the Mg2Zn11/CaPd5+x-type intergrowths revealed here, the interfaces run parallel to this axis. Using CP analysis of the Mg2Zn11/CaPd5+x-type parent structures, we trace this behavior to the different directions of high-CP compatibility of the interface nuclei in the Mg2Zn11/CaPd5+x and CaCu5/Laves structure type pairs. In this way, the Y(Ag/Zn)5+x phases highlight the role that interface nuclei play in directing the domain morphologies of modular intermetallic phases.

Technical note: Characterization of a single-beam gradient force aerosol optical tweezer for droplet trapping, phase transition monitoring, and morphology studies

Abstract. Single particle analysis is essential for a better understanding of the particle transformation process and to predict its environmental impact. In this study, we developed an aerosol optical tweezer (AOT) Raman spectroscopy system to investigate the phase state and morphology of suspended aerosol droplets in real time. The system comprises four modules: optical trapping, reaction, illumination and imaging, and detection. The optical trapping module utilizes a 532 nm laser and a 100 × oil immersion objective to stably trap aerosol droplets within 30 s. The reaction module allows us to adjust relative humidity (RH) and introduce reaction gases into the droplet levitation chamber, facilitating experiments to study liquid–liquid phase transitions. The illumination and imaging module employs a high-speed camera to monitor the trapped droplets, while the detector module records Raman scattering light. We trapped sodium chloride (NaCl) and 3-methyl glutaric acid (3-MGA) mixed droplets to examine RH-dependent morphology changes. Liquid–liquid phase separation (LLPS) occurred when RH was decreased. Additionally, we introduced ozone and limonene/pinene to generate secondary organic aerosol (SOA) particles in situ, which collided with the trapped droplet and dissolved in it. To determine the trapped droplet's characteristics, we utilized an open-source program based on Mie theory to retrieve diameter and refractive index from the observed whispering gallery modes (WGMs) in Raman spectra. It is found that mixed droplets formed core–shell morphology when RH was decreased, and the RH dependence of the droplets' phase transitions generated by different SOA precursors varied. Our AOT system serves as an essential experimental platform for in situ assessment of morphology and phase state during dynamic atmospheric processes.

Immobilization of simulated An4+ in radioactive sludge via microwave sintering: Mechanistic and performance

In this study, we investigate radioactive sludge containing An4+ ions via simulation. Ce4+ is employed as a surrogate isotope for An4+ ions, and silicate glass particles are incorporated as stabilizing agents. Continuous microwave sintering technology is adopted to sinter the simulated radioactive sludge with varying CeO2 contents co-doped with 60 wt.% glass particles at temperatures of 1100 °C, 1200 °C, and 1300 °C to achieve sample vitrification. The phase evolution, microstructure, morphology, chemical stability, sample density, and porosity of the sintered specimens are analyzed comprehensively. The results indicate distinct maximum solubility limits at different sintering temperatures: 5 wt.%, 6 wt.%, and 13 wt.% for 1100 °C, 1200 °C, and 1300 °C respectively. Under these conditions, Ce is immobilized within the glass network structure. Notably, the Ce3+/Ce4+ ratio in the 1300 °C-Ce10 specimen reaches 2.04, and the combined percentage of Q3 and Q4 glass structural units exceeds 50 %. Beyond the optimal solubility limit, tetragonal CeO2 crystals are formed on the glass sample surface. The normalized leaching rate of Ce from the samples remains at 5.0 × 10−6 g m−2 d−1. Additionally, the sintered samples indicate densities ranging from 2.65 to 3.01 g/cm3 and porosities from 0.18 % to 1.8 %. This study introduces a novel perspective for addressing radioactive sludge treatment.

Comparative evaluation of antimicrobial activity of spinel structured transition metal ferrites supported on reduced graphene oxide against pathogenic strains of bacteria and fungi.

One of the global challenges for living things is to provide pollution and harmful microbes-free environment. In this study, magnetically retrievable spinel-structured manganese zinc ferrite (Mn0.5Zn0.5Fe2O4) (MZF) was synthesized by a facile solvothermal method. Further, the MZF with different weight percentages (10wt%, 50wt%, and 80wt%) were supported on reduced graphene oxide (rGO). The phase purity and morphology of MZF and MZF/rGO nanocomposite were confirmed by X-ray diffraction technique and scanning electron microscopy, respectively. The Fourier transform infrared spectroscopy, Raman, UV-visible spectroscopy, and thermogravimetric analyses of the as-synthesized nanocomposites were examined for the detection of various chemical groups, band gap, and thermal properties, respectively. The MZF/rGO nanocomposite exhibited significant antibacterial and antifungal activity against Eggerthella lenta, Enterococcus faecalis, Klebsiella pneumonia, Pseudomonas aeruginosa, and Candida albicans compared to bare MZF and rGO. The high surface area of rGO plays a crucible role in antimicrobial analysis. Additionally, the anti-bacterial and fungal activity is compared by synthesizing various metal ferrites such as MnFe2O4, ZnFe2O4, and Fe3O4. The 50wt% MZF/rGO nanocomposite exhibits significantly high antibacterial activity. However, 10wt% MZF/rGO nanocomposite shows good antifungal activity than Fe3O4, MnFe2O4, ZnFe2O4, MnZnFe2O4, 50wt%, and 80wt% MZF/rGO nanocomposites. These findings suggest that the prepared ferrite nanocomposites hold promise for microbial inhibition.

High Temperature dry sliding wear behaviour of Selective laser Melted Ti-6Al-4V alloy surfaces

The present study investigates the sparsely documented tribological performance of selective laser-melted Ti-6Al-4V over a wide range of temperatures (room temperature to 450 °C). The evolution of wear mechanism was traced by examining the phase changes, chemical composition, and morphology of wear tracks in the material. The native oxide layer developed on the surface of the material was found to mitigate adhesive wear during dry sliding at room temperature. At elevated temperatures, this oxide layer contributed to oxidative wear, as evidenced by the formation of a tribo-oxide layer with increased oxygen penetration. Further, abrasive wear was found to increase with increasing temperatures, which could be attributed to the presence of entrapped oxidized wear particles (third-body wear) and material softening.

Multi-walled carbon Nanotube wrapped rare earth tungstate nanosheet composites for selective and rapid detection of sulfadiazine

Multi-walled Carbon Nanotube Wrapped Rare earth Tungstate Nanosheet Composites are developed for the ultrasensitive and selective electrochemical detection of sulfa drug, sulfadiazine (SAN) as they exhibit high levels of toxicity towards public health and ecosystem. Here, we synthesized Gadolinium tungstate decorated with multi-walled carbon nanotubes (Gd2WO6/MWCNT) though hydrothermal processing and characterized by XRD, SEM, EDX, TEM, and EIS measurement to investigate the phase purity, morphology, and interfacial property. Gd2WO6 is a double perovskite that has high oxygen surface exchange kinetics and the MWCNT possesses high catalytic capability and a larger surface area contributes to the efficient sensing ability. The Gd2WO6/MWCNT possessed a great electrical conductivity owing to the synergism between the Gd2WO6 and MWCNT. The synergistic effect increases the surface area and ionic and electrical conductivity which increases the current response of SAN. Under optimum conditions, the Gd2WO6/MWCNT/GCE displays a broad linear of 0.01 – 671 µM and a LOD level of 2 nM (S/N ratio: 3) with a sensitivity of 0.371 µA µM cm-1. The analytical applicability of the proposed electrode modifier leads to a promising sensor for SAN detection in human urine and water samples with appreciable results.

Transparent surface crystallized aluminosilicate glasses with an ultrahigh crack resistance

Overcoming inherent brittleness and poor crack resistance (CR) of inorganic glasses is crucial to widen their applications. By optimizing the thermal treatment scenarios, a transparent surface crystallized aluminosilicate glass with an ultrahigh CR (75.1 N) and high hardness (7.1 GPa) is fabricated. Compared with the as-prepared glass with the stoichiometric β-quartz s.s. composition (Li2O·Al2O3·2.5SiO2), a near 14 times enhancement in CR is exhibited, which could be one of the reported glasses with the highest CR. The evolution of phase compositions and morphologies with modifying thermal treatment protocols was revealed through characterization. And the processing parameter dependence behaviors of mechanical performances for these crystallized glasses is mainly ascribed to the alterations in grain size, preferred orientation, or fraction of β-spodumene s.s. and β-quartz s.s. crystal phases in the surface crystallized layer. These findings provide new insights for developing new transparent materials with ultrahigh crack resistance to fulfill the applications such as electronic screens.

Fabrication and wear behavior of TiC/TiB2-reinforced NiAl intermetallic matrix composites

Combustion synthesis (CS) is a well-known technique for manufacturing intermetallic compounds and intermetallic-matrix composite materials. This research focuses on fabricating NiAl-matrix composites with varying TiC/TiB2 contents as reinforcement, achieved by the combustion synthesis method. The chemical reactions that yield the final NiAl–TiC–TiB2 compounds were interpreted using thermodynamic calculations. The phase analysis and morphology of the composites were investigated using X-ray diffractometry (XRD) and scanning electron microscopy (SEM) characterization techniques, respectively. The findings demonstrate that the NiAl matrix contains evenly distributed TiC–TiB2 ceramic-based particles, and no oxidation of reactants occurred during the combustion reaction. With an increase in the TiC–TiB2 reinforcement phases from 0 to 15 wt %, the hardness of the NiAl–TiC–TiB2 product significantly rose from 496 to 1015 Vickers, while the porosity increased from 24% to 39%, attributed to the reduced quantity of melted NiAl available to fill the pores. Examining tribological behavior in synthesized composites involved combining experimental-numerical methods, utilizing sliding wear tests and artificial neural network (ANN) modeling. The wear results revealed decreasing wear rates with reduced loads (from 35 N to 25, and 15 N) and higher TiC/TiB2 ceramic content. Iron traces at C0 and C10 worn samples were 2.47 and 26.18 wt % respectively, which indicates enhanced hardness. The experimental data were used to train and test an artificial neural network (ANN) and statistical analysis revealed a remarkable accuracy of 91% for the ANN model in predicting friction coefficients within SHS-processed composites, as indicated by the R2 value of 0.91 and a MAPE of 6.47.

Production of novel Zr–Mg nanoceramics based on kaolinite clay with strong antibacterial activity

Gram-negative bacteria Pseudomonas putida, Gram-positive Bacillus subtilis, and Staphylococcus aureus were utilized as test samples to evaluate the antibacterial characteristics of DD3-clay/MgO and DD3+38 wt% ZrO2-clay/MgO nanoparticles. The ceramic powders prepared by a thermal autoclave method are characterized before and after Mg addition by SEM, EDX, XRD, IR, UV–visible, and TEM in order to investigate microstructure, phase, and surface morphology. The results showed that after adding Mg, it led to the deformation of the crystal lattices of (mullite, zirconium silicate, and zirconium oxide) together with a decrease in particle size (75–103 nm) and a complete change in its shape from nanotube to nanospherical, as observed by SEM and TEM analyses. It also confirmed by UV–visible spectroscopy that the addition of Mg increases the absorbance accompanying a decrease in the energy gap of 1.91, 1.74, 1.73, and 1.43 eV corresponding to DD3, DD3Z, DD3/30 wt% Mg and DD3Z/30 wt% Mg respectively. The antibacterial mechanism is related to the size of the particles, the solvent used for powder dissolution, the nanoparticle's size when they come into touch with bacteria, and the generation of reactive oxygen species (ROS: ˙O2−, ˙OH, and H2O2). It was observed that the anti-bacterial activity is enhanced with 10 wt% and 30 wt% of Mg added to a modified ceramic powder. Also, more O2− is formed on the surface of the prepared powder, which penetrates the bacterial cell and destroys it. The nanocomposite particles showed remarkable antibacterial activity when they were dissolved in DMSO compared to methanol and chloroform as organic solvents. The aim is to enrich knowledge on the antibacterial activities of metal nanoparticles (ZrSiO4 and MgO) on three bacterial strains with different Grams due to their extensive involvement in the phenomena of contamination and infection encountered in the medical field. The synthesized nanoparticles have good antimicrobial activity against all strains tested. A maximum inhibition zone of 35 ± 0.2 mm was obtained with S. aureus, a zone of 23 ± 0.46 mm with P. putida and a zone of 27 ± 0.46 nm with B. subtilis for DD3/30 wt% Mg and an inhibition zone of 38 ± 0.93 mm, 26 ± 0.24 nm and 17 ± 0.33 nm was obtained with same strains for DD3Z/30 wt% Mg, respectively.

Toughening poly(lactic acid) with novel polyolefin-graft-poly(lactic acid) copolymers maintaining high transparency and stiffness

The combination of well-balanced mechanical performance, high transparency and appealing eco-friendly attributes endows poly(lactic acid) (PLA) with significantly potential for wide-ranging applications in high-value packaging sectors. However, effectively toughening PLA without compromising its transparency and stiffness remains a formidable challenge. In this study, we synthesized a series of graft copolymers by incorporating hydroxyl-functionalized linear low density polyethylene (LLDPEOH) and copolymers of cycloolefin (COCOH) as the main chain and PLA as the side chain, which were subsequently employed as novel toughening agents for commercial PLA. The achievement of high-performance PLA blends with a balanced combination of toughness, strength, and transparency can be realized through meticulous tuning of the structure and mass fraction of the blended graft copolymers. The maximum elongation at break for the PLA blends increased by about 50 times that of neat PLA, reaching up to 300 %. Furthermore, these materials retained their high strength (54 MPa) and excellent transparency (light transmittance up to 90 %). The excellent properties of PLA blends could be ascribed to the well-designed chain structure of the graft copolymer which leaded to and excellent compatibility with the PLA matrix and unique phase morphology. This work is significant in guiding the design and synthesis of graft copolymers as toughening agents for PLA, thereby expanding its application range in areas where high transparency and toughness are required.

High stability and selectivity of butterfly pea flower extract-NiAl LDH-based catalysts in the tetracycline degradation.

Layered double hydroxide (LDH) is an applicable material that can be modified in various ways. Modifications using natural extracts fulfill the principles of "green chemistry." The preparation of butterfly pea flower extract (BPE)-modified NiAl LDH was completed using the calcination and restacking method. The characteristics of the prepared composites were identified through analysis of functional groups, crystal phase, bandgap energy, surface area and surface morphology. Fourier transform-infrared (FT-IR) characterization revealed that the active group of the catalyst is -OH except for NiAl layered double oxide (LDO), which has the metal oxide-like functional groups. X-ray diffraction patterns expressed a typical layered material structure of NiAl LDH dan NiAl LDH-BPE, but not for NiAl LDO and NiAl LDO-BPE. Introducing BPE into NiAl LDH and NiAl LDO effectively decreased the bandgap energy and changed the surface morphology. The prepared catalysts were applied in a batch system with pH 5 to degrade tetracycline (TC). NiAl LDO demonstrated the highest activity as a catalyst in TC degradation, with a 93.61% degradation rate. In contrast, NiAl LDO-BPE demonstrated the highest structural stability in TC degradation and repeated use, with an initial degradation percentage of 82.58% and a fifth regeneration percentage of 71.4%.

Investigating the influence of rotating magnetic field (RMF) on intermetallic compound crystallization, thermal and mechanical properties in lead-free Sn-Ag-Cu solder alloys during solidification

This research delves into the effectiveness of using rotating magnetic field (RMF) during the solidification process of Sn-3.5 wt% Ag-0.7 wt% Cu (SAC 357) alloy. The main goal is to evaluate the effect of RMF on the crystallization of intermetallic compounds (IMCs), as well as to study its implications for the thermal properties and creep resistance of the resulting alloy. It is found that the application of the RMF has a significant promotion effect on the improvement in the grain structure of the primary AgSn phase within the directionally solidified SAC 357 alloy. With the application of RMF, the morphology of the primary AgSn phase transformed from developed dendritic-like to fine needle-like, accompanied by a decrease in grain size, but shows no discernible impact on their composition. This observation is attributed to the influence of Lorentz force and thermo-electromagnetic convection. The implementation of a rotating magnetic field (RMF) resulted in notable enhancements in the thermal properties of the SAC357 solder alloy. Specifically, RMF application led to reductions in both the pasty range and melting temperatures, accompanied by a decrease in undercooling compared to conditions without stirring.The SAC357 alloy, when modified with a magnetic field, demonstrated the longest creep rupture time and higher creep resistance compared to those not subjected to magnetic field modification. This research endeavor aims to address a notable gap in our understanding concerning the behavior of SAC357 solder alloys when subjected to a Rotating Magnetic Field (RMF).

Effect of Matte-Sn Electroplating Parameters on the Thermo-mechanical Reliability of Lead-free Solder Joints

Most of the Cu/Cu alloy lead-frames of electronic components used for automotive applications contain  electroplated matte-Sn terminal finish to improve the wettability of Sn-based Pb-free solders during reflow soldering process. When the solder joints are subjected to combined thermal and mechanical cyclic loading, the influence of matte-Sn electroplating parameters can lead to early and brittle failure of the solder joint. To test this hypothesis, a factorial design of experiments (DOE) has been conducted with LFPAK-MOSFET (hereafter referred to as LFPAK) components plated with different matte-Sn electroplating parameters and reflow soldered with two solder alloys (SAC 305 and Innolot). The LFPAK solder joints were then subjected to thermo-mechanical in-phase cyclic loading under different strain amplitudes. No electrical measurement is done to eradicate the effect of electrical current on the solder joint. The response to the DOE is the crack percentage obtained in the LFPAK solder joints after 1000 and 2000 cycles. The Innolot solder joints exhibited lower crack percentages than the SAC 305. The level of organic additives in the electroplating process of matte-Sn influences the failure mode of the solder joint. Microstructural investigation attributes the nature of failure to the morphology of the (Cu,Ni)6Sn5 IMC phase that forms on the component side of the solder joint.

Influence of flux on morphological & optical properties of RE doped CaAl2Si2O8 phosphor

A series of RE (Eu2+, Dy3+, Eu2+/Dy3+) doped CaAl2Si2O8 phosphors has been synthesized via the combustion method. The influence of flux on the structural and optical properties of CaAl2Si2O8 phosphor has been investigated. XRD and SEM investigations confirm the phase purity and morphology of the prepared phosphor. Further, photoluminescence excitation and emission of the RE (Eu2+, Dy3+, Eu2+/Dy3+) doped CaAl2Si2O8 phosphor exhibit the characteristic bands of the RE ions. The energy transfer mechanism between Eu2+/Dy3+ doped CaAl2Si2O8 phosphor is studied, and the corresponding luminescence decay time of the rare ions is being reported successfully. Thus, RE (Eu2+, Dy3+, Eu2+/Dy3+) doped CaAl2Si2O8 phosphor is a promising and stable structure host for LED applications.

Tin–containing Silicon Oxycarbonitride Ceramic Nanocomposites as Stable Anode for Magnesium Ion Batteries

AbstractThe development of magnesium ion batteries as a viable alternative to lithium–ion batteries is impeded by the lack of efficient and stable electrode materials. Here, we present the synthesis of nanocomposites of tin–containing silicon oxycarbonitride (Sn/SiOCN) as anode materials for magnesium ion batteries (MIBs). The elemental and phase composition, morphology, and surface area of the nanocomposites are assessed by several characterization techniques. The galvanostatic cycling tests indicate a substantial initial discharging capacity for the anode with 42.2 wt . % of tin. Specifically, the first discharging capacities are 489.9 mA/g, 172.9 mA/g, and 136.6 mA/g at current densities of 0.5 mA/g, 50 mA/g, and 500 mA/g, respectively. After 100 cycles at a current density of 500 mA/g, the anode containing 33.8 wt % of tin exhibits a reversible capacity of 101.8 mAh/g and a remarkable rate performance efficiency of 76.5 %. Increasing tin content in the electrode materials increases the battery performance by decreasing electrode impedance and thus facilitating Mg2+ diffusion, as revealed by electrochemical impedance spectroscopy (EIS). Ex situ XRD and X‐ray photoelectron spectroscopy (XPS) characterizations following the magnesiation–demagnesiation process confirm the storage of reversible storage of Mg2+ ions in Sn/SiOCN electrode through incorporation in the SiOCN network and alloying/dealloying process involving Mg−Mg2Sn−Mg.

Morphology and properties of Mg2Si phase modified by Ge in Mg-Si alloys

The modification effects of Ge on Mg2Si phase in a Mg-2.5Si alloy were studied by computational simulation and experimental investigation. Based on first-principles structural prediction and electronic structure calculation, Mg2(SixGe1-x) phases were structurally stable and had sufficient hardness and inherent toughness as a reinforcement phase. With the increase of Ge content, due to the preferential adsorption of Ge atoms on the {100} planes of Mg2Si crystal, the morphology of primary Mg2Si crystal changed from equilateral-dendrite to polygonal, and finally to quadrilateral. In Mg-2.5Si-0.5Ge alloy, Ge was almost completely dissolved in the Mg2Si phase, but a small amount of dispersed solute segregation with a size of 10–20 nm can be observed. In Mg-2.5Si-1Ge alloy, many Mg2Ge precipitates with a small amount of Si dissolved having a size of 20–50 nm and a lattice constant a of 0.644 nm were uniformly distributed in primary Mg2Si, and only one orientation relationship (OR) in form of [001]Mg2Ge || [001]Mg2Si, (001) Mg2Ge || (001)Mg2Si with a tiny rotational angle of 0.39° was found. The stiffness and hardness of Mg2Si phase decreased with the increase of Ge content. Despite Mg2(SixGe1-x) crystal models only considering the solid solution of Ge and neglecting segregation and precipitation, the theoretical predictions of mechanical properties remained consistent with experimental results. This agreement was primarily due to the unique OR between Mg2Ge precipitates and Mg2Si phase.

Preparation of Sustainable Biobased Compounds of Pla/pbat/pbs;study on Processability there of

As a result of the overuse of conventional plastic products in daily applications by human being and as per data available only 9-10% is recycles out of whatever is produces to the date, compostable plastics such as poly (lactic acid) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT) have been extensively uses in many applications as an alternative to conventional plastics due to its biologically degradable properties. These plastics offer the circularity of the carbon cycle. However, each of them has advantages and disadvantages. PLA and PBAT are the polymers on which several researches have been done. Compounds of these two polymers have been prepares with and without chain extenders and properties have been studies. Now a days many compostable and biodegradable polymers have been synthesised, irrespective of its monomer root, whether naturally available or fossil bases. One of the newly developed polymer polybutylene succinate (PBS) has also gains the attention of manufacturers due to its unique properties. The ternary blend of PLA/PBAT/PBS are therefore very interesting in terms of phase morphology and their physical properties while offering compostable practices. In this work, we have prepared different blends of PLA/PBAT/PBS with and without use of chain extenders and calcium carbonate as a filler. Study has been done on blown film extrusion machine to evaluate processability.

Effect of heat treatment on the microstructure and nanoindentation behavior of AlCoCrFeNi high entropy alloy

In the present work, the effect of annealing temperature on the phase evolution, morphology, and nanoindentation behavior of the equiatomic AlCoCrFeNi high entropy alloy (HEA) were investigated, and the correlation between the microstructure and nanoindentation behavior in the dendrite core (DC) and inter-dendrite (ID) regions was revealed. The DC and ID regions in the as-cast alloy are composed of disordered A2 particles and ordered B2 matrix. As the annealing temperature increases, the volume fraction of the face centered cubic (FCC) phase first increases and then decreases, leading to complete dissolution of FCC phase at 1200 °C. In addition, annealing at 700 and 800 °C results in the precipitation of the σ phase in the ID region. DSC and thermodynamic calculations were used to analyze the phase evolution of the alloy with temperature. Changes in morphology and phase constituent inevitably affect the mechanical properties of the alloy, which were characterized by nanoindentation for both ID and DC regions. The results show that the ID region displays higher nano-hardness than the DC region in the as-cast and 600–800 °C samples, but there is no difference in the 900–1200 °C temperature range.