Melt Spinning Process Research Articles

Optimization of Planar Flow Melt Spinning Process for Producing Thin, Wide, and Continuous Amorphous Ribbons of Fe73.5Si13.5B9Nb3Cu1 Alloys

Optimization of Planar Flow Melt Spinning Process for Producing Thin, Wide, and Continuous Amorphous Ribbons of Fe73.5Si13.5B9Nb3Cu1 Alloys

Tunning Pr to achieve ultra-high magnetic properties of anisotropic nanocrystalline (Sm,Pr)Co5 magnets

In this study, we reported on the bulk anisotropic nanocrystalline Sm1-xPrxCo5 (x = 0.2–0.6) magnets aimed at achieving excellent energy products. Through a combination of advanced processing techniques, including melt spinning, hot pressing, and hot deformation process, bulk magnets with a fine nanocrystalline structure were successfully synthesized. The results revealed that the substitution of Pr strengthened the c-axis texture and the saturation magnetization, facilitating the enhancement of remanence (Mr) and maximum magnetic energy product [(BH)max]. However, Pr substitution decreased the coercivity (Hci) due to the reduced magnetocrystalline anisotropy field. Excellent magnetic properties are obtained for Sm0.4Pr0.6Co5 magnets with the (BH)max of 23.2 MGOe and Hci of 11.8 kOe. The prepared (Sm,Pr)Co5 magnets with different Pr contents have essentially the same microstructure with RECo5 main phase grains of about 400 nm in diameter and fine dispersed rare earth-rich nanoprecipitates. Our findings can provide reliable reference for manufacturing nanocrystalline permanent magnet materials and promote the development of rare earth permanent magnet new materials.

Effect of Linear Velocity on Magneto-mechanical Properties of Ni-Mn-Ga-Based Melt-Spun Ribbons

The study brings original data on the effect of linear velocity during melt-spinning process on magneto-mechanical properties of Heusler Ni-Mn-Ga-based melt-spun ribbons. The research revealed that different linear velocity of the copper wheel had a significant impact on the ribbon's geometry resulting in distinct changes in magneto-mechanical properties. X-ray diffraction measurements were used to examine the phase composition, confirming the presence of L21 austenite phase. To assess the mechanical properties of the Ni-Mn-Ga-based melt-spun ribbons, cyclic bending experiments were conducted at a strain rate of 0.1 mm/s. Additionally, experiments involving magnetic field-induced bending were carried out in an external magnetic field ranging from 0 to 0.28 T. Finally, it was observed that there was a proportional relationship between the linear velocity of the copper wheel and magnetic field-induced ribbons deflection. Conversely, the dependence between linear velocity and mechanical bending load was found to be inversely proportional. Electron backscattered diffraction measurements revealed that melt-spun ribbons produced at high linear velocity of 18.5 m/s exhibited fine-grained microstructure in contrast to low linear velocity of 3 m/s. Based on these results it seems feasible to optimize the functional properties of the studied ribbons by varying the linear velocity of the melt-spinning process.

Effect of aromatization degree of mesophase pitch on cracks and mechanical properties of mesophase pitch-based carbon fibers

The aromatization degree of MP is closely related to the orientation of carbon fibers, which determines their properties. To investigate the effect of the aromatization degree of MP on the properties of carbon fibers, this study prepared MP with varying aromatization degrees using the self-pressurization/N2-blowing two-stage thermal condensation method with refined coal tar pitch as raw material. Mesophase pitch-based carbon fibers (MPCFs) were obtained through melt spinning, pre-oxidation, and carbonization processes. Results show that the C/H atomic ratio rises from 2.067 to 2.318 as the aromatization degree of MP increases. After carbonization at 1300 ℃, the microcrystalline structure of MPCFs becomes ordered, with obvious axial radiation in the cross-section. The carbon layers in MPCFs are tightly stacked in parallel, significantly improving tensile strength and modulus. When the C/H atomic ratio of MP exceeds 2.262, the resulting MPCFs exhibit a maximum tensile strength of 1389 MPa and a maximum tensile modulus of 167 GPa. However, when the C/H atomic ratio of MP exceeds 2.318, the excessive aromatization degree makes the MPCFs structure prone to cracking due to circumferential volume shrinkage, and the appearance of cracks reduces the tensile strength of MPCFs.

Al-Ni-Co decagonal quasicrystal application as an energy-effective catalyst for phenylacetylene hydrogenation

Intermetallic catalysts, including quasicrystals, are considered a sustainable alternative to noble metal-based catalysts in hydrogenation reactions. This study discusses the manufacturing and catalytic potential of an Al-Ni-Co quasicrystalline alloy. Energy-effective and simple catalyst production was provided by a melt-spinning process. The obtained ribbons, characterized in terms of microstructure, phase and chemical composition using X-ray diffraction, scanning and transmission microscopy methods, were composed of a decagonal quasicrystalline phase with traces of crystalline phases. The form of the melt-spun ribbons ensured easy application in the phenylacetylene hydrogenation reaction. The catalyst provided a substrate conversion of approximately 80% and a styrene selectivity of 54% after 1 h of reaction carried out under mild conditions. The repeatability of the reaction course was verified, with a maximum deviation of 10%. Moreover, the catalyst recovered after the reaction was evaluated in terms of its phase composition and surface changes. X-ray diffractograms confirmed the phase stability, however, the surface degradation and oxidation occurred. The catalytic activity after three months of catalyst storage is also discussed.

Characterization of Melt-Spun Recycled PA 6 Polymer by Adding ZnO Nanoparticles during the Extrusion Process.

With recent technological advances and the growing interest in environmentally friendly fiber production processes, the textile industry is increasingly turning to the spinning of filaments from recycled raw materials in the melt spinning process as the simplest method of chemical spinning of fibers. Such processes are more efficient because the desired active particles are melt-spun together with the polymer. The study investigates the melt spinning of recycled polyamide 6 (PA 6) fibers modified with zinc oxide nanoparticles (ZnO NPs) in concentrations ranging from 0.1 to 2.0 wt% of the polymer. The extrusion process was optimized under laboratory conditions. An analysis of the effectiveness of the nanoparticle distribution and chemical composition was performed using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). The results of the thermal analysis show an increase in the glass transition temperature of the extruded material from 50.97 °C (raw polymer) to 51.40 °C to 57.98 °C (polymer modified with ZnO NPs) and an increase in the crystallization point from 148.19 °C to a temperature between 175.61 °C and 178.16 °C, while the molar enthalpy (ΔHm) shows a decreasing trend from 65.66 Jg-1 (raw polymer) to 48.23 Jg-1 (PA 6 2.0% ZnO). The FTIR spectra indicate PA 6 polymer, with a characteristic peak at the wavelength 1466 cm-1, but pure ZnO and PA 6 blended with ZnO show a characteristic peak at 2322 cm-1. The distribution of nanoparticles on the fiber surface is more or less randomly distributed and the different size of NPs is visible. These results are confirmed by the EDS results, which show that different concentrations of Zn are present. The mechanical stability of the extruded polymer modified with NPs is not affected by the addition of ZnO NPs, although the overall results of strength (2.56-3.22 cN/tex) and modulus of elasticity of the polymer (28.83-49.90 cN/tex) are lower as there is no drawing process at this stage of the experiment, which certainly helps to increase the final strength of the fibers. The results indicate the potential of modification with ZnO NPs for further advances in sustainable fiber production.

Enhanced melt flow UHMWPE/HDPE blends melt spinning and performance study

AbstractThe extremely low melt flowability of ultra‐high molecular weight polyethylene (UHMWPE) is the primary obstacle to its melt processing. Particularly in melt spinning processes, the extremely high molecular weight of UHMWPE and the density of entangled molecular chains severely limit its production efficiency and monofilament performance. This study investigates the effect of flow modifiers on the melt spinning process of UHMWPE/HDPE blends, focusing on CaSt2, PEG, and CaSt2/silicone powder composite additives, and their impact on the standard tensile samples and monofilament tensile properties of UHMWPE/HDPE. The mechanism of additive influence on the tensile properties of UHMWPE/HDPE blends is analyzed through tensile strength testing, thermal analysis, and microscopic morphology observation. The results show that in standard tensile samples, CaSt2 or CaSt2/silicone powder composite additives can enhance the crystallinity of the blend, thereby improving its tensile strength. Conversely, adding PEG significantly reduces the crystallinity and tensile strength of the blend. The maximum tensile strength of CaSt2‐modified UHMWPE/HDPE monofilament is 1236.61 MPa. This enhancement is attributed to the lubricating effect of CaSt2, which simultaneously assists the molecular chains in the amorphous region, and the reorientation of the stress‐induced molten lamellar structure under tension, greatly promoting the formation of straight‐chain crystals in the monofilament. During hot drawing, PEG inhibits the formation of straight‐chain crystals in the monofilament, resulting in a 3.06% decrease in maximum crystallinity compared with standard tensile samples. When CaSt2 is combined with silicone powder, the additives tend to aggregate during hot drawing, and these larger aggregate particles hinder the orientation of molecular chains along the drawing direction, resulting in a 30.75% decrease in maximum tensile strength of the monofilament compared with the standard tensile samples.Highlights The tensile property of UHMWPE/HDPE blends modified with additives was discussed. Analytical techniques including DSC, SEM, and tensile strength tests were used. The maximum tensile strength of the monofilament can reach up to 1236.61 MPa. UHMWPE/HDPE/CaSt2 = 60/40/0.5 exhibits the best tensile property.

Milling amorphous FeSiB ribbons with vibratory ball and disc mills

Fe, Si and B powders, mixed with atomic composition Fe78Si9B13, are subjected after arc melting to a melt spinning process, which is optimized to obtain the greatest amount of amorphous ribbon. The amorphous ribbons are milled to powder form in a vibratory ball mill and a vibratory disc mill, taking care of maintaining the amorphous character. Ribbons and powders have been characterized by X-ray diffraction (XRD), laser diffraction, SEM and TEM microscopy, and differential scanning calorimetry (DSC). The amorphous character and particle size of the powders are characterized as a function of the mill charge and the milling time. It is shown that the use of the ball mill is appropriate for obtaining small quantities of amorphous or nanocrystalline powder, while the disc mill can process larger quantities of powder in a shorter time. The particle sizes obtained for milling times between 10 and 150 min range between 26 and 412 μm, ready for use in powder metallurgy processes.

Rapidly solidified Al-Cu-Co quasicrystalline alloy: microstructure and catalytic properties

This study presents the characterisation and evaluation of the catalytic potential of an alloy with a composition referring to the quasicrystal from the Al-Cu-Co system. The material was synthesised through a melt-spinning process, providing rapid solidification conditions and a favourable material form of thin ribbons. Microstructural and chemical analyses were performed using scanning electron microscopy, X-ray diffraction and transmission electron microscopy methods. The obtained results confirmed the presence of a major phase which was a decagonal quasicrystal in the form of globular grains and additional crystalline phases occurring along the grain boundaries. The catalytic potential of the materials was explored using phenylacetylene hydrogenation. The catalyst, obtained by pulverising the ribbons, demonstrated catalytic activity with over 40% phenylacetylene conversion and selectivity exceeding 60% for styrene production under mild reaction conditions. The recovered catalyst displayed a stable phase composition, as confirmed by X-ray diffraction, and unchanged morphology, indicating the possibility of catalyst reuse for subsequent reaction cycles. The presented results provide insight into the experimental verification of the catalytic properties of the developed environmentally friendly catalysts.

Machine learning assisted mechanical properties prediction of fine denier polyester fiber

In recent years, more and more attention has been attracted by fine denier polyester fibers in electronic information industry due to their unique structural and excellent mechanical properties. As known, the mechanical properties of fine denier polyester fibers have a close relationship with their melt-spinning process parameters, thus, it is worth further exploring the influence of process parameters on fiber mechanical properties (namely breaking strength, elongation at break and CV of breaking strength). This study aims to develop a novel prediction model based on the artificial neural network (ANN) to predict the key mechanical properties of fine denier polyester fibers. For this purpose, firstly, different specifications of fine denier polyester fibers with different mechanical properties are produced by adjusting the key melt-spinning parameters, namely spinning temperature, take-roll speed and metering pump speed. Then the experimental data is collected, analyzed and augmented with effect to be used for modeling. Next, a novel prediction model based on ANN is developed by importing the two-streams structure and two attention matrices to improve the feature abstraction for mechanical properties prediction. Lastly, different predictive performance indicators, namely root mean square error (RMSE), mean absolute percent error (MAPE) and the coefficient of determination (R2) are imported to evaluate the proposed model. For the total of three mechanical properties, the predicted results of the proposed model in terms of RMSE, MAPE and R2 are respectively 0.3499, 0.0906 and 2.9516.

Analysis and optimization of the heat transfer behavior in the melt-spinning process of Nd-Fe-B ribbons

Heat transfer plays a significant role on the quality of Nd-Fe-B ribbons in the melt-spinning (MS) process. In this paper, the heat transfer behavior in the MS process of Nd-Fe-B ribbons was investigated by experiment and simulation. A full flow channel heat transfer model with high accuracy is established using the “fluid-thermal” coupling method. The temperature distribution of the cooling roller and fluid field in steady-state is obtained. The simulated and experimental results of the outlet temperature are compared and the relative error is within 5%. The microstructures of the free surface and roller-sticking surface of Nd-Fe-B melt-spun ribbons are characterized by FE-SEM, and the refined grains are formed on the roller-sticking surface of Nd-Fe-B ribbons due to rapid solidification caused by the heat transfer from the roller. Moreover, a multi-nozzle structure is proposed for the MS process. The temperature distribution on the surface of the cooling roller in the axial direction is more uniform compared with the original single-nozzle structure, and the average convective heat transfer coefficient is increased by about 1.27 times after the modification of multi-nozzle structure, with a productivity of three times. Finally, the experimental design method of Latin hypercube sampling response surface design is used to obtain the response surface relationships of rotational speed, inlet flow rate, and water inlet temperature on the surface temperature of the cooling roller, respectively. NSGA-II multi-objective genetic algorithm (MOGA) is adopted for multi-objective optimization of process parameters. The optimized combination of process parameters is obtained with a relative error of about 0.41%. The research results are helpful to understand the heat transfer behaviors in the MS process of Nd-Fe-B ribbons, improve the utilization rate of the cooling roller and enhance the production efficiency in the actual application.

Influence of Complex Plasticizer on Plasticizing Effects and Rheological Properties of Plasticized Poly(Vinyl Alcohol)

AbstractPoly(vinyl alcohol) (PVA) was modified using D‐mannitol (DM) and 1‐butyl‐3‐methylimidazole bromide (BMIMBr) as the complex plasticizer (DB), and PVA/DB composite was prepared. The plasticizing effect of DB on PVA was studied by Fourier transform infrared spectroscopy (FT‐IR), differntial scanning calorimetry (DSC), thermos gravimetric analysis (TGA) and melt flow indexer (MI). FT‐IR analysis indicated that Br− of BMIMBr and OH of DM could form H‐bonds with OH of PVA. With the increase of DB, the melt temperature (Tm2) and crystallization temperature (Tc1) of PVA/DB composite decreased, the initial thermal decomposition temperatures (Td), thermal processing window (ΔT) and MI values increased respectively. Based on above studies, the influence of DB content on rheological properties of PVA/DB composite was investigated by the capillary rheometer. The result displayed that apparent viscosity of PVA/DB composite decreased with increasing DB content, shear rate and measured temperature. The non‐Newtonian index (n) increased and structural viscosity index (Δη) decreased with the increase of measured temperature and DB. The viscous flow activation energy (Eη) decreased as the shear rate and DB content increased. When the measured temperature, DB content and shear rate were in the range of Tm2+30 −Tm2+35 °C, 40–50 wt% and 764.8–1504.9 s−1, respectively, the spinnability of PVA/DB composite was optimal, which will lay a theoretical foundation for the exploration of melt spinning process in the future.

Hybrid processing of melt electrospinning/blowing for polypropylene/polyethylene glycol fiber fabrication with various diameter distribution

Many studies have been conducted to develop and optimize the manufacturing process of polymer fibers in various forms. In particular, many melt-spinning processes have been developed for the manufacture of nanofibers of polymer materials with excellent chemical resistance. In this study, we investigated the effects of various spinning conditions and their spinning behavior on the fiber manufacturing process and properties using a melt electrospinning/blowing process that combines conventional melt blowing and electrospinning. We also report a discontinuous spinning process that produces a web with a very wide diameter distribution from the nanoscale to the microscale with gradient fibers. They are generally compared with webs, which have a narrow diameter distribution. We believe that by using this process, it is possible to produce diameters of various distributions in one step. These results show remarkable potential for many applications in which gradient fibers are required.

Electric conductive fibers from extrinsic conductive fillers with thermoplastics by melt spinning

Abstract The aim of this review is to identify the literature for the scientific work to understand the basics of the conduction mechanism of electrically conductive filament yarns made from extrinsic con-ductive fillers and thermoplastic polymer using melt spinning. In recent years, extrinsic conductive fillers have become very popular due to their electrical conductivity and have received greater research attention. In general, extrinsic conductive fillers are carbon-based conductive materials. These include carbon black (CB), carbon nanotubes (CNT), graphene and graphite. This thematic review mainly focuses on the thermal, mechanical and electrical properties of melt-spun thermoplastic polymers, such as polypropylene, polyamide, poly(ethylene terephthalate), thermoplastic polyurethane, polycarbonate, polyimide, poly(methyl methacrylate and poly(L-lactide)) acid with CB, CNT, graphene and graphite. The structure, shape, size and properties of extrinsic conductive fillers are described in this review. The development of electrically conductive filament yarns from extrinsic conductive fillers using the melt spinning process requires a consideration of the entire process, from pre-treatment, compounding and melt spinning of the extrinsic conductive fillers to the drawing of the electrically conductive filament yarn. In order to achieve better spinnability of the two different components (conductive filler, thermoplastic polymer), an overview of the pretreatment methods of the extrinsic conductive filler and thermoplastic polymers is given. Mixing of inorganic nanomaterials into a polymer matrix involves many challenges, like agglomeration, poor dispersion and scattering of the extrinsic conductive filler within the thermoplastic polymer. Therefore, the most important influencing factors of the melt spinning process are discussed in detail in this review. Depending on the type of polymer (amorphous, crystalline, semi-crystalline), extrinsically conductive fillers can influence the crystallization process in different ways. The textile mechanical and electrical properties of the spun extrinsically conductive yarn will be comprehensively highlighted. Finally, new developments in the field of conductive filament yarns are presented

Thermal Analysis of a Casson Boundary Layer Flow over a Penetrable Stretching Porous Wedge

This work aims to analyze the Casson thermal boundary layer flow over an expanding wedge in a porous medium with convective boundary conditions and ohmic heating. Moreover, the effects of porosity and viscous dissipation are studied in detail and included in the analysis. The importance of this study is due to its applications in biomedical engineering where the analysis of behavior of non-Newtonian blood flow in arteries and veins is desired. Within the context of blood flow, it is also applicable to many other fields, for instance, radiative therapy, MHD generators, soil machines, melt-spinning, and insulation processes. The modeled problem is a set of PDEs, which is nondimensionalized to derive a nonlinear boundary value problem (BVP). The obtained BVP is solved using the shooting technique, endowed with the order four Runge-Kutta and Newton methods. The impact of different parameters on the momentum and temperature fields is investigated along with two important parameters of physical significance, i.e., the Nusselt number and the surface drag force. Results are validated, and an excellent agreement is seen for the parameters of interest using MATLAB built-in function bvp4c. A significant finding is that by increasing the Casson liquid parameter, the velocity decreases as the wedge expands quicker than the free stream velocity at R=2. However, the velocity increases for the case when R=0.1. A decrease in the Darcy number increases the temperature profile. Furthermore, the convective parameter accelerated the heat transmission rate, and a rise in the Prandtl number thickens the thermal boundary layer. The findings of this investigation contribute to problems in fluid dynamics and heat transfer that involve studying the behavior of a non-Newtonian fluid with Casson rheological properties near a solid porous wedge surface.

Structure and properties of chlorogenic acid-loaded polylactide fiber prepared by melt spinning

Polylactide/chlorogenic acid (PLA/CGA) blends with different weight ratios were prepared by melt mixing, and corresponding PLA/CGA fibers were produced via a two-step melt spinning process. For PLA/CGA blends, CGA was distributed uniformly in the PLA matrix. The intermolecular interactions between CGA and PLA existed. The viscosity of PLA/CGA blends was much lower than that of neat PLA. With the increase of CGA content, the viscosity of PLA/CGA blends decreased. As the CGA content increased, the crystallinity of both PLA/CGA blends and fibers decreased. In addition, the tensile strength of PLA/CGA fibers was slightly lower than that of neat PLA fiber. For PLA/CGA fibers, the 6-fold drawn PLA/CGA fiber with 3 % CGA owned the highest tensile strength of 420 MPa. The ultraviolet (UV) resistance of PLA/CGA fibers were enhanced significantly by the introduction of CGA. When the CGA content was not <3 %, the UV transmittance of PLA/CGA fibers was <8 %. Moreover, PLA/CGA fibers exhibited good antioxidant properties. PLA/CGA fibers with 10 % CGA owned the highest antioxidant rate of >90 %. In addition, the 6-fold drawn PLA/CGA fiber with 10 % CGA presented excellent release performance with a 7-day cumulative CGA release rate of 19 %.

A Short Review on the Evolution of Magnetocaloric La(Fe,Si)13 and Its Fabrication through Melt Spinning.

Energy-efficient refrigeration technology needs to advance ineluctably due to rising energy consumption and diminishing fossil fuel and primitive hydrocarbon reserves. Further, the existing gas compression method releases huge amount of chlorofluorocarbons (CFCs) that deplete the ozone layer. This is a global concern, which demands an immediate remedial technology. As a potential solution to the problem of sustainability and a means of meeting the ever-increasing demand for energy, environmentally friendly and socially responsible renewable energy sources could serve as an ideal replacement for traditional refrigeration technology. Solid-state refrigeration using magnetocaloric materials is one prominent technique that can be adopted for clean and economical refrigeration or cooling requirements. In this review, we briefly introduce the present understanding on magnetocaloric LaFe13-xSix alloys with a specific emphasis on their application in magnetic refrigeration. This paper deals with the advantages and disadvantages of different synthesis methods for producing LaFe13-xSix and enhancing its magnetocaloric effects. Annealing time, yield, composition, and relative cooling power are examined as prospective industrial implementation factors for the La(Fe,Si)13 synthesis process. The initial sections have been devoted to an overview of the magnetocaloric effect and its different types and history. Further, the article reviews the evolution of a new preparation method called melt spinning, other synthesizing methods, and some developments around the world for the prototypes of La(Fe,Si)-based magnetic refrigeration methods. According to the findings in the scholarly literature, the synthesis process of melt spinning has the potential to be commercialized because of its capacity to create huge quantities of La(Fe,Si)13 with a high purity in a very short amount of time.

Effects of Magnetic Fe Doping on the Thermoelectric Properties of TiNiSn Nanomaterials prepared via melt spinning method

As a kind of high temperature thermoelectric material, TiNiSn compound has the characteristics of high power factor and high thermal conductivity. Its thermoelectric performance is largely limited by the high thermal conductivity. In this paper, TiNiFexSn(x=0-0.05) samples are prepared by melt spinning combined with spark plasma sintering method. The results show that there are nanocrystals existed in the samples with a size of around 200nm. The grain size of the samples is refined through the melt-spinning process, and the lattice thermal conductivity is lower compared with the arc-melted samples. With the increase of Fe content, the lattice thermal conductivity of TiNiFexSn samples decreases, reaching a minimum value of 3.31W/mK when x=0.02, which is 44% lower than that of TiNiSn matrix. The carrier concentration of TiNiFexSn samples increases due to the doping of Fe, resulting in an increase of electrical conductivity and decrease of Seebeck coefficient and finally improvement of the power factor. The maximum zT value of TiNiFe0.03Sn sample is 0.54 at 900K, which is 35% higher than that of TiNiSn samples. This work shows that the melt spinning and magnetic Fe doping can effectively improve the thermoelectric properties of TiNiSn.

A comparative study of the activation energy and shielding properties of some binary and ternary echo-friendly alloys reinforced by Bi substitutes Zn particles for radiation protection

The thermal and mechanical stability besides environmentally friendly of some low-melting binary systems dopant with third element such as Bi started to gain much attention. This study provides the synthesized, effects of rapid solidification processing (RSP) and Bi doping on the microstructural, mechanical performance and gamma radiation shielding of various lead-free binary and ternary alloys have compositions Sn-(50-x)Zn-xBi (where x = 0, 10, 20, 30 and 40 wt.%) using high cooling rate. Microstructure modifications, elastic and plastic behavior were investigated. As well as the gamma-ray shielding performance of all as-prepared melt-spun process alloys was examined experimentally using FH 40G dose rate measuring unit. Phy-X/PSD software was used to compute the μ m values across a large energy range of 0.015 MeV–15 MeV. To clearly understand the gamma radiation shielding capability of the melt-spun process alloys, different shielding parameters includes linear attenuation coefficients, LAC, mass attenuation coefficient, MAC, mean free path, MFP, half value layer (HVL) and tenth value layer (TVL) were calculated and compared to other commonly shielding materials. X-ray diffraction (XRD) analysis confirms the presence of different phases such as β-Sn, Bi, Zn as well as two IMCs Sn0.95Bi0.05 and Sn0.85Zn0.15. The morphology features of the samples using scanning electron microscopy (SEM) revealed that Bi particles dopant the matrix led to refine the microstructures as well as forming a uniform and homogeneous distribution of IMCs. It is also, reported that the increase of Bi dopant led to enhancing the Bi segregation in the matrix in addition to decreasing the crystallite size which reinforces the mechanical strength and radiation shielding properties. The elastic modulus and Vickers microhardness increase with increasing Bi additions to about 35% and 27%, respectively. The results showed that correlation between activation energy and shielding properties of as-prepared alloys. The mass and linear attenuation coefficient for all prepared samples increases as Bi increases from 10 to 40 wt.%. On the other hand, low activation energies indicate easier formation and growth of IMCs. The results also show that the Sn-10Zn-40Bi alloy has the highest mechanical and shielding attenuation properties. It may be attributed to promoting the brittleness of Bi, refinement of crystallite size, extended the solid solubility and microstructure features accompanying Bi content using rapid cooling. As a result, Sn-10Zn-40Bi alloy may be recommended as a preferable alloy for radiation shielding performance to be used for medical, industrial and nuclear waste storage fields. In the current work, an attempt has been made not only to summarize the various investigations made so far on visualizing the feasibility of alloys as radiation shielding material; but also, to provide a comparative study for further consideration to be used in other fields.

Thermoelectric properties of Co doped TiNiCo&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Sn alloys fabricated by melt spinning

Although TiNiSn-based half-Heusler thermoelectric materials obtain high power factors, their high lattice thermal conductivity greatly hinders the improvement of thermoelectric properties. In this work, TiNiCo&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Sn (&lt;i&gt;x&lt;/i&gt; = 0–0.05) samples are prepared by melt spinning combined with spark plasma sintering method, and their phase, microstructure and thermoelectric properties are studied. The XRD results show that the main phase of all samples is TiNiSn phase, and no any other impurity phases are found, indicating that the high purity single phase can be prepared by rapid quenching process combined with SPS process. In the solidification process, the large cooling rate (10&lt;sup&gt;5&lt;/sup&gt;–10&lt;sup&gt;6&lt;/sup&gt; K/s) is conducive to obtaining the uniform nanocrystalline structure. The grains are closely packed, with grain sizes in a range of 200–600 nm. The grain sizes decrease to 50–400 nm for the Co-doping samples, which indicates that Co doping can reduce the grain size. For the &lt;i&gt;x&lt;/i&gt; = 0 sample, the thermal conductivity of the rapid quenching sample is significantly lower than that of bulk sample, with an average decrease of about 17.8%. Compared with the TiNiSn matrix, the Co-doping sample has the thermal conductivity that decreases significantly, and the maximum decrease can reach about 38.9%. The minimum value of lattice thermal conductivity of TiNiCo&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Sn samples is 3.19 W/(m·K). Therefore, Co doping can significantly reduce the &lt;i&gt;κ&lt;/i&gt;&lt;sub&gt;l&lt;/sub&gt; values of TiNiCo&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Sn (&lt;i&gt;x&lt;/i&gt; = 0.01–0.05) samples. With the increase of Co doping amount &lt;i&gt;x&lt;/i&gt;, n/p transition is observed in the TiNiCo&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Sn samples, resulting in gradually reducing the conductivity and the power factor, and finally deteriorating the electrical transport performance, of which, the TiNiSn sample obtains the highest power factor of 29.56 W/(m·K&lt;sup&gt;2&lt;/sup&gt;) at 700 K. The &lt;i&gt;ZT&lt;/i&gt; value decreases with the Co doping amount &lt;i&gt;x&lt;/i&gt; increasing, and the maximum &lt;i&gt;ZT&lt;/i&gt; value of TiNiSn sample at 900 K is 0.48. This work shows that the thermal conductivity of TiNiSn can be effectively reduced by using the melt spinning process and magnetic Co doping.