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Recent Advances in Welding Processes for High-Entropy Alloys: A Comprehensive Review
(2026-01-01)
Li, Min
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Pimsarn, Monsak
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Chuwattanakul, Varesa
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Eiamsa-Ard, Smith
High-Entropy Alloys (HEAs) have gained attention for their exceptional mechanical properties, corrosion resistance, and unique microstructure. However, welding HEAs remains challenging, attributed to intricate microstructures, inadequate thermal conductivity, and elevated melting points. This review systematically summarizes recent advances in metal welding of HEAs with both similar and dissimilar alloys, including stainless steel, titanium alloys, aluminum alloys, and nickel-based alloys. Welding techniques, including Gas Metal Arc Welding (GMAW), Laser Welding (LW), Electron Beam Welding (EBW), and Gas Tungsten Arc Welding (GTAW) are critically compared in terms of joint microstructure, mechanical performance, and corrosion behavior. The influence of filler composition, heat treatment, and process parameters on weld quality are discussed. Key challenges, including microstructure evolution under complex service conditions and controlling brittle intermetallic phases, are identified. Finally, potential research directions and application prospects of HEA welding in advanced manufacturing are outlined.
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Influence of Graphene Oxide Nanoparticles on the Mechanical Behavior of Stereolithography Printed Polyether Ether Ketone Composites
(2026-01-01)
Ramkumar, N. P.
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Sharma, S. C.
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Adarsha, H.
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Shaik, Nagoor Basha
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Anurakparadorn, Kanat
The objective of this work is to analyze the impact of graphene oxide percentage on the mechanical behavior of polyether ether ketone (PEEK) nanocomposites produced by stereolithography. The dispersion of graphene oxide (GO) nanoparticles was analyzed using both the scanning electron microscopes and transmission electron microscopes. The mechanical properties of nanocomposites were analyzed by performing hardness and tensile tests in accordance with ASTM standards. The morphology of the final product shows a consistent distribution of GO nanoparticles and a robust interfacial bonding between the nanoparticle reinforcement and the PEEK matrix. It is found that the nanoparticles enhanced the dimensional stability of the nanocomposites, resulting in lower dimensional tolerance compared to the pure PEEK material. The microhardness test has been carried out on the samples, demonstrating the beneficial effect of nanoparticles; the PEEK nanocomposite containing 0.75% nanoparticles gives a higher hardness value of 71 VHN. The strength of nanocomposites was found to increase due to the robust interfacial cohesion between GO and PEEK, resulting in enhanced hardness. Here, the hardness exhibits a negative impact on elongation, which yields a declining trend from (1.7 ± 0.6)% to (1.4 ± 0.6)% with an increase in graphene oxide nanoparticles.
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Hybrid Natural Fiber Composites of Polylactic Acid Reinforced with Sisal and Coir Fibers
(2025-01-01)
Sriseubsai, Wipoo
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Praemettha, Ariya
This study explored the tensile and impact strength of polylactic acid (PLA) through the incorporation of sisal and coir fibers. Hybrid natural fiber composites were prepared using PLA as the matrix and sisal and coir fibers as the reinforcements. The hybrid composites were prepared with an internal mixer, followed by compression molding. A constrained mixture design was employed to determine the optimal material combinations and their effects on the tensile and impact strength. Confirmatory experiments based on response surface methodology revealed no significant differences in the data means at the 0.05 significance level. PLA reinforced with sisal fibers alone exhibited the highest tensile strength of 75.36 MPa but demonstrated a low impact resistance of 12.94 kJ/m2 at a 95.22:4.78 (PLA:sisal by volume) ratio. Conversely, the maximum impact resistance of 36.71 kJ/m2 was achieved with PLA and coir at the same ratio. An optimal blend, consisting of 95.22% PLA, 0.78% sisal, and 4.0% coir by volume, resulted in a tensile strength of 51.08 MPa and an impact strength of 26.59 kJ/m2, outperforming other mixtures and pure PLA in the mechanical properties. Additionally, water absorption tests showed that reinforcement with sisal and coir fibers increased both water absorption and stability over 60 h.
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Performance of Environmentally Friendly Concrete Containing Fly-Ash and Waste Face Mask Fibers
(2024-12-01)
Nawaz, Adnan
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Khan, Ameer Murad
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Jirasakjamroonsri, Amorntep
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Saingam, Panumas
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Ejaz, Ali
This work was carried out to explore the potential use of used face masks in concrete to develop sustainable green concrete. In this experimental study, used face masks were cut up, removing the ear stripes and internal nose steel wire, to prepare elongated fibers. These fibers were incorporated in cement fly ash mixtures as an additive to determine the response of M20-grade concrete. The Class F fly ash (FA) was employed as a fractional substitute of cement up to 25% by weight, whereas the addition of face masks occurred at 0%, 0.125%, and 0.25% by volume of concrete. The testing scheme focused on the mechanical and durability characteristics of the cement FA mixtures carried out after 3, 28, and 60 days of curing. The inclusion of FA and face mask fibers reduced the density of concrete specimens. The compressive, splitting tensile, and flexural strengths of mixes were also reduced at an early age; however, the strength characteristics improved at later ages, compared to the control mix. The combination of both materials in concrete mixtures resulted in lower water absorption, lower bulk water sorption, and lower mass loss values against acid attack at later ages. Similarly, the electrical resistance of concrete substantially enhanced by increasing the percentage of both materials. The experimental results demonstrated that processed face masks can be utilized in cement fly ash mixes without significantly compromising the resultant concrete characteristics.
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Research on the application of impedance control in flexible grasp of picking robot
(2023-04-01)
Zhuang, Min
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Li, Ge
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Ding, Kexin
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Xu, Guansheng
Aiming at the damage of fruit picking robot during the picking process, an impedance control method of picking robot with parameter self-tuning is proposed. The rheological properties of fruit during picking by manipulator were studied by Burger’s viscoelasticity theory, and the variation characteristics of fruit deformation during picking, as well as the changing law between fruit contact force and deformation were obtained. On this basis, the impedance control system model of the picking manipulator is established, and the impedance controller is designed. Finally, by constructing the self-correcting change function of impedance parameters, the influence of different impedance parameters on the change of the contact force is studied, and then the control system is improved and designed. The simulation and experimental results show that the established impedance control system model can effectively realize the non-destructive grasping of fruit, and has high grasping accuracy. The expected grasping force is smoother, the overshoot of the contact force is greatly reduced, and the adjustment time is also shortened, which indicates that the control method proposed in this paper has certain application value in the control of picking robots.
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Microstructure and mechanical properties of Ti-Zr alloys fabricated by two-step spark plasma sintering from TiH2 and ZrH2 powders
(2023-01-01)
Banjongaxsorn, Kunpot
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Khantachawana, Anak
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Watanabe, Chihiro
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Srirussamee, Kasama
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Kondoh, Katsuyoshi
Ti is well-known for its high strength-to-weight ratio and biocompatibility. It can be alloyed with Zr to improve mechanical properties. Currently, Ti-Zr alloys can be fabricated by powder metallurgy using Ti and Zr powders, although high oxidation reactivity and cost could still be an issue. In this study, premixed TiH<inf>2</inf> and ZrH<inf>2</inf> powders were used to prepare Ti-Zr binary alloys with different Zr contents of 0–30 mass% ZrH<inf>2</inf> via dehydrogenation and sintering by spark plasma sintering (SPS) process. α-Ti and δ-TiH<inf>2</inf> phases coexisted in the sintered Ti-Zr alloys, and a characteristic lamellar microstructure was formed. The tensile strength of the Ti-Zr alloys increased with increasing Zr content due to the solid solution effect, grain refinement and the appearance of δ-TiH<inf>2</inf> phases, although the elongation was reduced. This study shows that the fabricated Ti-Zr alloys possess controllable mechanical properties, which can be beneficial for biomedical and other engineering applications.
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EFFECT OF h-BN AS AN ADDITIVE ON PHYSICAL AND MECHANICAL PROPERTIES OF Al2TiO5 COMPOSITE
(2023-01-01)
Treetornkeerati, Paramapat
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Hankoy, Montree
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Kitiwan, Mettaya
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Rodchom, Mana
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Vichaphund, Supawan
Aluminum titanate (Al<inf>2</inf>TiO<inf>5</inf>) is a promising material for high-temperature applications due to its low thermal expansion, high melting point, and excellent corrosion resistance. In this study, the effect of h-BN addition on the properties of Al<inf>2</inf>TiO<inf>5</inf> composites was investigated. The composites were prepared by sintering a mixture of Al<inf>2</inf>O<inf>3</inf> and TiO<inf>2</inf> at a 1:1 molar ratio, with varying amounts of h-BN (5-20 mol%) added to the mixture. The samples were sintered at 1,500ºC for 4 h in N<inf>2</inf> atmosphere, and the bulk density, porosity, phase transition, microstructure, flexural strength, and hardness of the composites were investigated. XRD analysis confirmed the presence of Al<inf>2</inf>TiO<inf>5</inf>, Al<inf>2</inf>O<inf>3</inf>, and Al<inf>18</inf>B<inf>4</inf>O<inf>33</inf> phases in the composites. The addition of h-BN in increasing amounts from 5 to 20 mol% resulted in a gradual improvement in the bulk density, flexural strength, and hardness of the Al<inf>2</inf>TiO<inf>5</inf> composites. The composite with the highest h-BN content (20 mol%) exhibited a bulk density of 3.12 g/cm3, as well as the highest flexural strength and hardness values of 123.6±8.9 MPa and 11.2±4.1 GPa, respectively.
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Influence of Cu content on microstructure, grain orientation and mechanical properties of Sn–xCu lead-free solders
(2022-04-01)
KANLAYASIRI, Kannachai
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MOOKAM, Niwat
The effect of Cu content on the microstructure, grain orientation and mechanical properties of Sn–xCu (x=0–4.0 wt.%) lead-free solder was studied. Results showed that added Cu induced the formation of intermetallic phases. Only the η-Cu<inf>6</inf>Sn<inf>5</inf> and ɛ-Cu<inf>3</inf>Sn phases were present in the β-Sn matrix. For all contents, the strongly preferred orientation of the β-Sn phase was formed on the {001} plane. In Sn doped with 1.0 wt.% Cu, the η-Cu<inf>6</inf>Sn<inf>5</inf> phase exhibited the preferred orientation of {0001} plane, whereas doping with 3.0 or 4.0 wt.% Cu transformed the preferred orientation to the {010} plane. In addition, only the {0001} and planes were present in the ɛ-Cu<inf>3</inf>Sn phase. The high Cu contents contributed to an increased number of low-angle boundaries, high residual strain, tensile strength and microhardness.
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Effect of Nb Content and water quenching on microstructure and mechanical properties of Ti-Nb alloys fabricated by spark plasma sintering
(2022-01-01)
Suesawadwanid, Nattawood
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Khantachawana, Anak
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Srirussamee, Kasama
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Kondoh, Katsuyoshi
Titanium-niobium (Ti-Nb) alloys have been extensively studied for medical implants due to their advantageous mechanical properties and biocompatibility. However, the stress shielding effect remains a challenge. This research investigated the effects of Nb content and enhancement of α′′ formation on the mechanical properties of Ti-xNb alloys (x = 0, 5, 15 and 25%) fabricated by spark plasma sintering. Water quenching from the β phase induced α′′ phase formation in Ti-5Nb and Ti-15Nb samples, thereby reducing their Young’s modulus values but was not observed in commercially pure titanium (CP-Ti) and Ti-25Nb. Results showed that heat treatment with water quenching induced α′′ phase formation and can be used to tailor the properties of Ti-Nb alloys fabricated by SPS. This technique can also be used to enhance material ductility at high β-stabilizer content, as observed in Ti-25Nb samples.
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Effects of hot air and microwave drying on kinetic rate and mechanical property of oil palm veneer
(2017-01-01)
Lekachaiworakul, Puttipong
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Dangvilailux, Panya
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Rattanamechaiskul, Chaiwat
This research was studied, the hot air and microwave drying of Oil Palm Veneer (OPV). The oil palm trees at 27 years of age were collected from a plantation in Chumphon. They were processed into a dimension of 80 x 150, 1 mm (thickness) and initial moisture 345 % (db.). The chamber of oven is size of 500 x 1,000 x 1,000 mm3. It had an electrical heater at maximum power output of 5,000 watts, air speed of 2.1 m/s and the microwave power level of 1,000-4,000 watts. The final moisture content reached 10±2% (db). The results were showed that while OPV drying with the hot air condition used temperature about 50, 70 and 90 °C reached the target value within 70, 32 and 16 min respectively, the microwave condition used to power about 2,000 and 3,000 watts reached the target value within 62 and 34 min, combined condition used hot air 50°C with microwave power level 2,000 and 3,000 watts, hot air 70 °C with microwave power level at 2,000 and 3,000 watts and hot air 90 °C with microwave power level 2,000 and 3,000 watts reached the target value within 24, 20, 14, 10, 10 and 8 min respectively. Moreover, drying with hot air and microwave on high power revealed the tensile stress and shear properties increased. However, the hot air at 70, 90 °C combines with the microwave power level 2,000 watts were better than mechanical properties of hot air at 70, 90 °C combines with microwave power level 3,000 watts. The results showed the drying of hot air at 90 °C combine with the microwave power level at 2,000 watts, mechanical properties of OPV dried tensile stress at 1.9447 MPa, shear stress 19.0286 MPa, which used of energy 39 kWh, its surface was cracked burns. Therefore, the drying hot air only conditions at 90 °C can be recommended for mechanical properties, tensile stress 1.8229 MPa, shear stress 18.4472 MPa, used of energy 21 kWh, which was OPV suitable and cost optimality.

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