Melting Point Temperature Research Articles

Surface morphology, microstructure and emissivity of rhenium electrodeposited from molten salts

Rhenium (Re) has a high melting point and unique high temperature mechanical properties, making it an optional material that acts as a high emissivity coating on the outer wall of iridium/rhenium combustion chambers, improving their radiant heat dissipation. In this study, the effects of the electrodeposition (ED) process parameters in molten salts on the surface morphology, microstructure, and emissivity of Re coatings were investigated. The emissivity of the coating was related to the oxygen content, preferred orientation and, particularly, its morphology. The emissivity of the Re coatings increases with decreasing average radius or increasing surface density of the coating characteristic microstructures. With increasing cathodic overpotential, corresponding to high CsCl content or high current density or low molten salt temperature, the Re coating tended to change from lateral growth mode to outward growth mode, with preferred growth plane of the coating changing from (200) to (110), and meanwhile the surface morphology of the Re coating changing from stout branch-like to spiked starfish-like, leading to an increase in emissivity. The optimal deposition process parameters for the high emissivity black Re coatings were as follows: temperature ranging from 720 °C to 780 °C, cathode current density of 50 mA/cm2 to 90 mA/cm2, and the CsCl content higher than 60 wt%. The obtained black Re coatings had an emissivity higher than 0.7, with a preferred growth crystal plane of (110), and a typical spiky starfish shaped micromorphology.

Impact of Multiple Reprocessing on Properties of Polyhydroxybutyrate and Polypropylene.

Biobased plastics have the potential to be sustainable, but to explore their circularity further, current end-of-life options need to be broadened. Mechanical recycling is one of the most accepted methods to bring back plastics into the loop. Polyhydroxybutyrates (PHBs) are biobased and biodegradable in nature with promising properties and varied applications in the market. This study focuses on their potential for mechanical recycling by multiple extrusion cycles (E1-E5) and multi-faceted characterization of the virgin (V) and reprocessed materials from E1 to E5. The behavior is compared to polypropylene (PP) as a reference with a similar property profile, which has also been reprocessed five times. The thermal properties of both series showed a stable melting point and thermal decomposition temperature from thermal analyses (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). However, a steady increase in the degree of crystallinity was observed which could counterbalance the decrease in molecular weight due to repeated extrusion measured by gel permeation chromatography and resulted in similar values of tensile strength across the cycles. The strain at break was impacted after the first extrusion, but no significant change was observed thereafter; the same was observed for impact strength. Even in scanning electron microscopy (SEM) images, virgin and E5 samples appeared similar, showing the stability of morphological characteristics. Fourier transform infrared spectroscopy (FTIR) results revealed that no new groups are being formed even on repeated processing. The deviation between the PHB and PP series was more predominant in the melt mass flow rate (MFR) and rheology studies. There was a drastic drop in the MFR values in PHB from virgin to E5, whereas not much difference was observed for PP throughout the cycles. This observation was corroborated by frequency sweeps conducted with the parallel plate method. The viscosity dropped from virgin to E1 and E2, but from E3 to E5 it presented similar values. This was in contrast to PP, where all the samples from virgin to E5 had the same values of viscosity. This paper highlights the possibilities of mechanical recycling of PHB and explains why future work with the addition of virgin material and other additives is an area to be explored.

Fluidized Bed Reactor Modeling and Simulation with Aspen Plus

Fluidized bed reactor is useful for heterogeneous (multiphase) reactions, separations, size enlargement, coating, and blending in chemical and pharmaceuticals industries. To develop a model and simulation of this reactor with advanced systems process engineering software (Aspen Plus). Aspen plus has the capability to simulate real factory performance, design improved plants, and intensify profitability in present plants. This modeling and simulation are applied Geldart B particle classification, GGC is used for particle size distribution function, Newton parameters for mass convergence, and Ergun equation is used for minimum fluidization velocity calculation and pressure drop through the fluidized bed reactor. Generally, most of the predictions model from Aspen plus is a reasonable agreement through the experimental results. Advantage of this investigation is used small quantity of bed particles and identified their melting point temperature is above 340°C. This fluidized bed reactor model and simulation is functional for aluminum hydroxide decomposition reaction. The feed 275 kg/hr of Al(OH)3is converted into 169.6 kg/hr of aluminum oxide (Al2O3) and 89.9 kg/hr of water. A total mass conversion percent is 94.4% of aluminum hydroxide.

Effect of initial/tail of the pulse waveform on surface morphology of AZ31 magnesium alloy laser spot welding

Effects of initial/tail of the pulse waveform on coupling efficiency and surface morphology of AZ31 magnesium alloy laser spot welding is investigated. Research shows that initial ramp-up waveform can improve the laser spot welding absorptance, but with limited effect (0.88 → 0.9), and melting time of ramp-up waveform is longer than rectangular for equal pulsed energies, making the welding energy coupling efficient and diameter larger. The ramp-down waveform can extend duration (9 ms → 12 ms) of molten pool above melting point temperature (630 °C), increase Marangoni number (R1: 29.29, R2: 32.11, R3: 23.70, R4: 26.62), slow down cooling rate (3 × 106 °C/s → 1 °C/s) and recoil pressure (R3: 52.90 P0 → 12.16 P0, R4: 95.95 P0 → 20.58 P0) of instantaneous closure of rectangular waveform, reduce the sensitivity of welding defects such as overfill, undercut and spatter, and improve the surface morphology of laser welding spots.

The roles played by anionic and cationic species in the curing process of aromatic nitrile resins

Understanding the curing mechanism of aromatic nitrile (AN) resins is crucial for improving their curing efficiency. Blending the Bronsted acid-containing aromatic nitrile monomers (ACN) and Bronsted base-containing aromatic nitrile monomers (BCN) is a novel approach that simultaneously lowers the melting point and rapid curing reaction temperature of AN resins. To investigate the impact of anionic and cationic species on the curing behavior of ACN-BCN blends, a series of ACN-BCN blends were designed and synthesized. DSC and TGA results demonstrated a significant improvement in the curing efficiency when ACN and BCN blended, the curing temperature decreased by more than 50 ℃, accompanied by a decrease in melting point. According to the DMA results, the Tg of the cured substance of the system can reach 405 ℃ at the curing temperature of 325 ℃. The curing behaviors of ACN-BCN blends were studied through thermal analysis and spectroscopic analysis, which indicates that cationic species can polarize the cyano rather than attack the cyano groups, promoting their curing reaction. Moreover, it was determined that while cationic species play a polarizing role on the cyano, active anionic species attack the cyano, serving as the rate-determining step in the curing process of ACN-BCN blends.

Thermal conversion kinetics and solubility of soy isoflavones in subcritical water extraction.

The conversion of isoflavones during subcritical water extraction were studied using first-order reaction kinetics modeling. Isoflavones were extracted from soybean using temperatures from 100℃ to 180℃ for 3 to 30min. It was found that malonylgenistin was the most thermally unstable, with little being detected above 100℃. The optimal extraction temperatures for acetylgenistin (AG), genistin (G), and genistein (GE) were 120℃, 150℃, and 180℃, respectively. A larger sum of the numbers of both hydroxyl groups and oxygen molecules was associated with a lower melting point and optimal extraction temperature. Kinetics modeling of reaction rate constant k and activation energy Ea showed that all of the reaction rates tended to increase with temperature, with the relationship fitted well by a first-order model in nonlinear regression. For temperatures between 100℃ and 150℃, AG→G and AG→GE conversions showed the highest rate constants, but G→GE and G→D3 (degraded G) conversions became dominant at 180℃. Chemical compounds studied in this article: genistein (PubChem CID: 5280961), genistin (PubChem CID: 5281377), 6″-O-malonylgenistin (PubChem CID: 15934091), 6″-O-acetylgenistin (PubChem CID: 5315831).

Thermal and Dielectric Characteristics of Aluminum Nitride/HTV Silicone Composites

The study describes the use of nano aluminum nitride in developing thermally conductive and electrically insulating materials. An experimental approach is followed, starting with the hydrophobic surface treatment of nanofillers using HMDS. TEM and XRD analysis are used to confirm the nanofiller presence and gain insight regarding the filler shape, dimensions, and phase. EDX, FTIR and XRD analysis revealed the co-existence of aluminum oxide in traces along with aluminum nitride. XRD patterns revealed no change after surface modification and confirmed the presence of an amorphous functionalized layer. The protocol for composite compounding is described in detail. SEM analysis of composites revealed a moderate degree of dispersion with localized pockets of agglomeration. Further, the TEM analysis performed gave insight into the dispersion of nanofillers. Finally, DSC analysis is performed to understand the effects of nano aluminum nitride on glass transition, melting point, and crystallization temperatures. An interesting pattern of increase in glass transition temperatures with nanofiller loading levels is discussed, drawing attention to the aggregated filler effect and the disentangling of silicone chains with increasing interfacial interaction. TGA analysis revealed an early onset of degradation with increase in nano aluminum nitride loading levels. Thermal conductivity increased with nanofiller loading levels, peaking at 3 phr by weight. Dielectric studies of breakdown strength and frequency domain spectroscopy from 1 mHz to 1 KHz is studied under different thermal points. The results are presented and discussed here.

Biodegradable Polyhydroxyalkanoates with a Different Set of Valerate Monomers: Chemical Structure and Physicochemical Properties.

The properties, features of thermal behavior and crystallization of copolymers containing various types of valerate monomers were studied depending on the set and ratio of monomers. We synthesized and studied the properties of three-component copolymers containing unusual monomers 4-hydroxyvalerate (4HV) and 3-hydroxy-4-methylvalerate (3H4MV), in addition to the usual 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) monomers. The results showed that P(3HB-co-3HV-co-4HV) and P(3HB-co-3HV-co-3H4MV) terpolymers tended to increase thermal stability, especially for methylated samples, including an increase in the gap between melting point (Tmelt) and thermal degradation temperature (Tdegr), an increase in the melting point and glass transition temperature, as well as a lower degree of crystallinity (40-46%) compared with P(3HB-co-3HV) (58-66%). The copolymer crystallization kinetics depended on the set and ratio of monomers. For terpolymers during exothermic crystallization, higher rates of spherulite formation (Gmax) were registered, reaching, depending on the ratio of monomers, 1.6-2.0 µm/min, which was several times higher than the Gmax index (0.52 µm/min) for the P(3HB-co-3HV) copolymer. The revealed differences in the thermal properties and crystallization kinetics of terpolymers indicate that they are promising polymers for processing into high quality products from melts.

The implementation of fusion properties calculation to predict wax deposition

Deposition of wax on the pipe walls is one of the complex flow assurance problems that causes a decrease and complete blockage of oil production rates by reducing the cross-sectional area of flow in the pipelines. In addition, surface facilities require higher energy consumption and failure of facilities due to wax plugging. Effective design of oil recovery processes requires an adequate prediction of the thermodynamic conditions in which wax can precipitate from crude oil, depending on the pressure, temperature, and composition of the oil. In this paper, the modified melting and pour point temperatures were presented based on the fluid description. Other fusion properties such as the enthalpy of fusion, the solid-state transition enthalpies, and the heat capacity of fusion have been calculated to modify the multi-solid model for predicting wax deposition. The proposed modified equations for melting and pour point temperatures were showing reliable agreement with experimental data based on SARA analysis and demonstrated more accurate results compare to literature data. In order to justify the proposed model, the comparative approach has been implemented between literature, experimental, and data obtained based on proposed solutions. The detailed description of the Republic of Kazakhstan’s (RoK) oil fields, components from C1 up to C36+ has been used during this research and the most crucial components which tend to form wax precipitation from C15H32 to C20H42 were plotted, which showed an increasing accuracy of 11 % for melting point temperature and 7 % for pour point temperature compared to literature data. As a result, the proposed modified solutions for fusion properties demonstrated good agreement with literature and obtained results of modifications can be used for further research on Multi solid model of wax precipitation

Recycling of spent LiFePO4 batteries by oxidizing roasting: Kinetic analysis and thermal conversion mechanism

The recycling of spent lithium-ion batteries has gained increasing attention due to its economic and environmental benefits. The oxidizing roasting has been preliminarily proven to be a feasible method to pre-treat and recycle spent LiFePO4 battery. However, the kinetics and thermal conversion mechanism of spent LiFePO4 battery during oxidizing roasting process remains indefinable and needs to be elucidated. Therefore, the kinetic analysis and thermal conversion mechanism of the spent LiFePO4 battery during the oxidizing roasting process were investigated in this study. The results indicated that the oxidizing roasting process of the electrode materials (LiFePO4 and C) could be divided into four weight loss stages, and the maximum weight loss took place in the third weight loss stage (500–800 °C). The model-free methods (Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose models) could well describe the oxidizing roasting process, and the corresponding Eα obtained were 257.38 and 255.35 kJ/mol respectively. The model-fitting methods showed that the three-dimension diffusion model was the most suitable kinetic reaction model for the electrode materials oxidizing roasting process. The graphite in the electrode materials could be easily oxidized to CO2 (the major gaseous product). Besides, the LiFePO4 was firstly oxidized and converted into Li3Fe2(PO4)3 and Fe2O3. Then the Li3Fe2(PO4)3 was decomposed into Li3PO4 and P2O5. Finally, P2O5 could react with Fe2O3 to form FePO4. The physical state of oxidizing roasting products changed from powder to molten state from 600 to 800 °C because of the lower melting point temperature of Li3Fe2(PO4)3, and the oxidizing roasting temperature was suggested to be controlled below 800 °C. The final products obtained from the oxidizing roasting process of the spent LiFePO4 battery electrode materials were Li3Fe2(PO4)3, FePO4 and Li3PO4. This study provides a comprehensive understanding of the kinetics and thermal conversion mechanism during spent LiFePO4 battery oxidizing roasting recovery process.

Thermal management of lithium-ion battery module using the phase change material

One of the significant challenges in the fast adoption of electric vehicles in the market is the thermal management of the battery pack. The current advancement in active and passive cooling techniques is helping resolve this issue in electric vehicles. The present work focuses on the use of passive cooling techniques, such as phase change material (PCM) and the heat sink, to maintain the battery module temperature within the thermal safety limit. The cartridge heaters were used as the mock-up cells. A 3 × 3 array of mock-up cells was formed with a cell-to-cell spacing of 6 mm. OM42 was used as a PCM with a melting point temperature of 44°C and latent heat of fusion, 199 kJ/kg. The experiments were conducted at different power settings of 10–40 W with an interval of 10 W. A heat sink was integrated into the bottom of the battery module. It was observed that increased power input reduces the time required to reach the operating temperature limit of 60°C. After incorporating the PCM, this time was extended by 100.8%, 35.5%, 24.7%, and 21.2% for the power input of 10, 20, 30, and 40 W, respectively. Cell-5 was found to be the most heat-affected cell in the battery module. At higher power inputs of 30 and 40 W, the temperature variation along the height of cell-5 was more than 5°C with and without the PCM. The present findings provide more insights into the heat dissipation at lower and higher power inputs, which may help designers to modify the existing battery thermal management system design efficiently.

Investigating the crystallization behavior of TiO2 during annealing: Molecular dynamics simulations

TiO2 is a dielectric material with excellent photocatalytic and photochemical properties. The conversion of TiO2 from an amorphous to crystalline phase significantly improves the photocatalytic activity of TiO2. However, the crystallization behavior of TiO2 during annealing has been little studied in the field of molecular dynamics. In this paper, the crystallization behavior of TiO2 during annealing under different conditions was analyzed using molecular dynamics simulation. To investigate the phase transition process of TiO2, the melting point temperature of the system was calculated by mean square displacement at about 2400 K. The effect of size on structural stability was explored. The radial distribution function and x-ray diffraction curves revealed that the anatase phase appeared over 800 K. Moreover, with the increase in annealing temperature, the anatase content in TiO2 first increased and then decreased, and the rutile phase gradually increased. At a specific temperature, a structure is formed where rutile and anatase coexist. Anatase atoms compete with rutile atoms, and by increasing the temperature, anatase is converted to rutile. The amorphous structure is reduced at high temperatures, improving the crystalline quality. The crystallization behavior of the amorphous structure can improve the photocatalytic efficiency of TiO2. TiO2 nanometers have good prospect for application. Therefore, studying the crystallization behavior of TiO2 is essential.

Improving the thermostability of a novel PL-6 family alginate lyase by rational design engineering for industrial preparation of alginate oligosaccharides

Alginate is degraded into alginate oligosaccharides with various biological activities by enzymes. However, the thermostability of the enzyme limits its industrial application. In this study, a novel PL-6 alginate lyase, AlyRm6A from Rhodothermus marinus 4252 was expressed and characterized. In addition, an efficient comprehensive strategy was proposed, including automatic design of heat-resistant mutants, multiple computer-aided ΔΔGfold value calculation, and conservative analysis of mutation sites. AlyRm6A has naturally high thermostability. Compared with the WT, T43I and Q216I kept their original activities, and their half-lives were increased from 3.68 h to 4.29 h and 4.54 h, melting point temperatures increased from 61.5 °C to 62.9 °C and 63.5 °C, respectively. The results of circular dichroism showed that both the mutants and the wild type had the characteristic peaks of β-sheet at 195 nm and 216 nm, which indicated that there was no significant effect on the secondary structure of the protein. Molecular dynamics simulation (MD) analyses suggest that the enhancement of the hydrophobic interaction network, improvement of molecular rigidity, and denser structure could improve the stability of AlyRm6A. To the best of our knowledge, our findings indicate that AlyRm6A mutants exhibit the highest thermostability among the characterized PL-6 alginate lyases, making them potential candidates for industrial production of alginate oligosaccharides.

Synthesis of a polyester with a liquid crystalline silsesquioxane-contained backbone Chain

A one-pot multistep growth melt procedure utilizing multistep feeding has been developed to enable the synthesis of thermoplastic polymers based on 4-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA)with greater numbers of alternating units in their backbone chains. The decreased melting point (Tm) and glass transition temperature (Tg) indicated that the multistep feeding procedure helped to enhance the flexibility of the backbone chain due to the increasing number of alternating blocks, due to a reduction in the stacking between different main-chains, thus enabling the formation of liquid crystalline polyester (LCP) fibers with oriented structures. The covalent incorporation of rigid cage-like silsesquioxane groups led to a significant reduction of the melting point, resulting from the inevitable transformation of the original symmetrical backbone structure to a less ordered structure, due to the steric effect and hybrid feature of silsesquioxane. The presentation of silsesquioxane groups also enhanced the aggregation of ultrafine fibers with well-aligned orientation in the molten state and produce stronger fiber bundles.

Comparative study of micro-sized Al particles enhancing the thermal joining of aluminum alloy-PA66 without or with reinforcement

The huge thermal difference between the aluminum alloy and polymer led to a low interface bonding strength, hindering the application of hybrid joints in the industries. Micro-sized aluminum (Al) particles were introduced into the polyamide 66 (PA66) resin substrates to improve the laser thermal joining of aluminum alloy to PA66 considering the heat conduction of metal particles. Results indicated the resin was physically reinforced after adding Al particles, enhancing the melting point and decomposition temperature due to the constraint on the polymer chain movement. The surface energy of PA66 resin was also increased because of the increase of polar functional groups, resulting in an enhancement of adhesion force between the aluminum alloy and resin. Furthermore, 3D thermally-conductive network formed between particles and resin substrates owing to the thermal vibration caused by Al electrons during the heat conduction, thereby strengthening the thermal conductivity of resin. This improved the thermal microscopic conductance at the interface, and the joining area at the interface dependent on the molten resin was thus enlarged. Finally, the tensile-shear force and strength of joints after adding Al particles were both significantly improved, reaching 1.35 times and 1.44 times of those without Al particles under the optimal heat input, respectively. This was achieved by a synergetic strengthening effect of enhanced adhesion force and joining area, providing a new method to obtain the high-quality joints.

Techno-economic evaluation of photovoltaic thermal system integrated with porous phase change materials: Case studies in China

This study aims to to develope a comprehensive mathematical model for predicting the performance, environmental impact, and economic viability of solar photovoltaic thermal (PVT) systems, with specific focus on the use of Porous Phase Change Material (PPCM) into a PVT system (PVT-PPCM) and its effect on the cooling cycle temperature throughout the year. The model was experimentally validated and implemented in Matlab to assess the performance of various systems, including PV-only, PVT, and PV integrated with PCM (PV-PCM). To determine the optimum melting point temperature for the PCM-based systems, a sensitivity analysis was conducted for different locations in China. The annual performance, CO2 reduction, discounted payback time (DPBT), and Levelized cost of energy (LCOE) were predicted for each system. Subsidy-free method was used for economic evaluation, which only shows system’s cost savings. In addition, it is worth noting that the maximum power output of each system was evaluated to be 1 MW. The results of the study showed that PVT-PPCM exhibited the highest annual power output of 1920 MWh and CO2 reduction of 30 tons/year, while the LCOE ranged from 0.02 to 0.58 CNY/kWh and the DPBT varied from 5 to 20 years across the case studies. The study also compared the Levelized cost of electricity (LCOEel) of PVT and PVT-PPCM with cases in UK and Spain, with the lowest LCOEel of PVT recorded in Kunming at 0.4 CNY/kWh.The significance of this study lies in its identification of the strengths and weaknesses of PVT system designs across different climates, highlighting areas for improvement. By providing insights into system performance, environmental impact, and economic feasibility, this research contributes to the advancement and optimization of PVT technology for sustainable energy applications.

Melting Behaviour under Pressure of Kaolinite Clay: A Nanoscale Study

In this study, the curves of variation of melting temperature as a function of pressure were determined for pressures up to 20 GPa using molecular dynamics (MD) calculations. The CLAYFF force field is used for the simulated PT curve of the clay kaolinite structure. For this purpose, we have adopted the Z-method to determine the melting point (Tm) and superheat limit temperature (TLS) for different densities in kaolinite clay. In addition, various quantities, such as the radial distribution function (RDF), the mean square displacement (MSD), and the diffusion coefficient were evaluated in order to ensure the solid behaviour at the superheat limit temperature and the liquid behaviour at the melting point for the equilibrated structure of kaolinite.

Ambient relative humidity effects on mechanical properties of FDM 3D printed PLA components

In this study, poly(lactic acid) samples were printed by using the fused deposition method whereas ambient relative humidity conditions and filling percentages varied. The effects of the relative humidity on the mechanical and thermal properties of the samples were investigated. It was observed that the mechanical properties of the samples decreased as the relative humidity increased and that specimens with low filling percentages were affected more by relative humidity. Differential scanning calorimetry results showed that the glass transition temperature, melting point, and crystallization temperature were inversely correlated with relative humidity. The surface structure was also negatively affected by the relative humidity, and the intensity and size of the voids increased as the relative humidity increased. In addition, this study recommends that the manufacture of materials with a 3D printer be conducted at low humidity to achieve high flexural strength and modulus.

Development and characterization of a quaternary nitrate based molten salt heat transfer fluid for concentrated solar power plant

Over the past few years, there has been growing interest in using inorganic quaternary nitrate-based molten salt mixtures as a highly effective heat transfer fluid (HTF) for concentrated power plants, primarily because they can achieve low melting temperatures. However, the high viscosity of these salt mixtures is still a significant challenge that hinders their widespread adoption. The high viscosity leads to high pumping power requirements, which increases operational costs, and reduces the efficiency of the Rankine cycle. To address this challenge, this study developed and characterized a novel quaternary molten salt, focusing on the effect of LiNO3 additions on the salt's viscosity, thermal conductivity, melting point temperature, heat capacity, and thermal stability. The quaternary mixture comprised KNO3, LiNO3, Ca(NO3)2, and NaNO2, with varying percentages of each salt. The study utilized various standard techniques to examine the characteristics of the developed mixture. Results showed that increasing LiNO3 content led to a decrease in melting temperature, higher heat capacity, improved thermal stability, conductivity, and reduced viscosity at solidification temperature. The lowest endothermic peak for the new mixture emerged at 73.5 °C, which is significantly lower than that of commercial Hitec and Hitec XL, indicating better potential for use as a heat transfer fluid for concentrated solar thermal power plant applications. Furthermore, the thermal stability results showed high stability up to 590 °C for all the samples examined. Overall, the new quaternary molten salt shows promise as a potential replacement for current organic synthetic oil, offering a more efficient solution.

Microstructures and properties of nanocrystalline W-based alloys produced by resistance sintering under ultrahigh pressure

W-2.5 wt% Y (WY) alloy with an average grain size of 9 nm and W-2 wt% TaC-2.5 wt% Y (WTY) alloy with an average grain size of 13 nm, were successfully prepared by resistance sintering under ultrahigh pressure (RSUHP) at low temperature, and the relative density of WY and WTY is 95.0% and 94.7%, respectively. The microstructure characterization and theoretical calculation results show that the inhibition of W grain growth can be mainly ascribed to the thermodynamic aspect. The Vickers hardness of nanocrystalline WY and WTY alloys is 1770 ± 62 kgf/mm2 and 1626 ± 36 kgf/mm2, respectively, and their Vickers hardness is much higher than that of coarse-grained W-based alloys, and the mechanisms of their ultrahigh hardness were revealed. The deviation of the Hall-Petch relationship in WY and WTY alloys was found as the dislocation pileup model is not applicable. Deuterium (D) plasma irradiation experiments on nanocrystalline WY at the irradiation dose of 1.2 × 1024 D/m2, 2.4 × 1024 D/m2, and 3.6 × 1024 D/m2 were conducted, respectively. Blisters can be found at three irradiation doses in nanocrystalline WY alloy, the blister areal density and blister size increase with the increase of irradiation dose, and the roles of grain boundaries (GBs) on the irradiation behaviors were illustrated. This article broke through the contradiction between the high melting point and low recrystallization temperature of W, and provided an experimental basis and theoretical guidance for the design and development of high-performance novel nanocrystalline W-based alloys.