Short Heat Treatment Research Articles

Thermoreversible Apparel Adhesives to Enable Sustainable Garment Assembly

AbstractOver 90 million tons of fabric waste are generated annually by the apparel industry and there exists an urgent need to develop innovative approaches for the recycling of garments. Reversible adhesives can both enable the automation of labor‐intensive assembly processes and facilitate fabric recycling for a circular apparel economy. Herein, an adhesive formulation based on thermoreversible Diels–Alder chemistry has been developed via the combination of a furan‐functionalized methacrylate copolymer (F) with a bismaleimide (M). To establish the fine balance between adhesion strength and reversible bonding, an extensive screening on the optimal composition and molar mass of F is conducted. Methyl, 2‐ethylhexyl, and lauryl methacrylate are used to tune the Tg of F copolymers, whereas H‐bonding monomers such as methacrylic acid and 2‐hydroxyethyl methacrylate are utilized to strengthen the adhesive and improve its interactions with cotton. Following the optimization of F composition, F molecular weight, and M crosslinker, the scaled‐up thermoreversible adhesive is studied by rheometry and successfully dispensed via an automated assembly platform. The adhered fabrics are tested for the required shear and peel strength and then separated for fabric recycling by a short heat treatment followed by a simple solvent wash to remove adhesive residues.

Study on Friction Properties of CNTs/AlSi10Mg Composites

Abstract The purpose of this study was to explore the effect of eutectic silicon particle size on the properties of composites of carbon-nano tubes (CNTs) and AlSi10Mg prepared by powder metallurgy. The samples were studied using light microscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, friction tests and tensile experiments. The effects of short-term heat treatment (540 °C solid solution for 1 h 175 °C aging for 4, 5, and 6 h) on the microstructure, tribological properties and tensile properties of the CNTs/AlSi10Mg composites were investigated. The results showed that the composite material showed an obvious toughening effect after 1 h of solid solution treatment and 4 h of aging, and the elongation increased by 33 %. Adding CNTs can improve the friction performance of the material. The composite material has the best friction performance when aged for 5 h. After a short heat treatment, the eutectic silicon is homogenized in the α-Al matrix, and the eutectic network is broken. The eutectic silicon becomes rounded from the lath shape. The spheroidized structure reduces stress concentrations around silicon particles and improves the friction performance of the composite material.

A new strategy for preparing high strength and high precision diffusion bonding GH536 joints via pulsed current and subsequent heat treatment

GH536 as a typical solid solution strengthened Ni-based superalloy, has been widely used in the preparation of laminated cooling structure. Diffusion bonding, which is highly promising as a joining process in laminated cooling structure, generally requires high strength and high precision. However, the high strength joint fabricated by the conventional hot pressure diffusion bonding (HPDB) often leads to severe deformation of base materials. Here, we developed a new diffusion bonding strategy to overcome this issue in GH536 via pulsed current diffusion bonding (PCDB) and subsequent heat treatment. At low temperature and short time (900 °C/30 min), a joint with a high shear strength of 535 MPa and a low deformation rate of 0.42 % was obtained using the PCDB, and these were 1.60 times and 0.28 times that of the conventional HPDB joint, respectively. Meanwhile, the low bonding temperature and short bonding time hindered the formation and coarsening of carbides, allowing them to be eliminated in a short time heat treatment. The unbonded zones healing, carbide dissolution and recrystallization during heat treatment significantly improved the joint shear strength, and the joint shear strength after heat treatment reached 561 MPa.

The effect of metal/non-metal ratio on the microstructure and magnetic properties of (MnFe)x(P0.5Si0.5) microwires

The effects of metal/non-metal ratio (M/NM ​= ​x: 1) on the microstructure and magnetocaloric properties of promising melt-extracted Mn–Fe–P–Si microwires with short heat treatment have been investigated here. More Fe2P principal phase, which is considered favorite for magnetocaloric effect (MCE), should achieve at low M/NM ratio and the fraction of Fe2P phase increased with the reduction of x. Meanwhile, the (Mn, Fe)3Si impurity phase is formed for x ​= ​2.00–1.90 whereas change to (Mn, Fe)5Si3 structure for x ​= ​1.85. It's worth noting that a metal deficiency resulted in the thermal hysteresis (Thys) and the magnetic hysteresis loss (Wy) decreased by ∼40 ​%., The magnetic transition temperature (Ttran), peak value of isothermal magnetic entropy change (−ΔSisopeak), refrigerant capacity (RC) and effective refrigerant capacity (RCE) first increased then decreased with the decrease of x, and reached the maximums at x ​= ​1.90, i.e., 370 ​K, 26.0 ​J ​kg−1 ​K−1, 367.4 and 339.8 ​J ​kg−1, respectively. Therefore, the customizable microstructure and magnetic properties of the melt-extracted (MnFe)x(P0.5Si0.5) microwires will be achievable effectively by tuning M/NM ratio x, and optimized Mn–Fe–P–Si compounds with novel thermomagnetic properties will be obtained.

Instantaneous Thermal Energy for Swift Synthesis of Single-Atom Catalysts for Unparalleled Performance in Metal-Air Batteries and Fuel Cells.

Based on experimental and computational evidence, phthalocyanine (Pc) compounds in the form of quaternary-bound metal-nitrogen (N) atoms are the most effective catalysts for oxygen reduction reaction (ORR). However, the heat treatment process used in their synthesis may compromise the ideal structure, causing the agglomeration of transition metals. To overcome this issue, a novel method is developed for synthesizing iron (Fe) single-atom catalysts with ideal structures supported by thermally exfoliated graphene oxide (GO). This is achieved through a short heat treatment of only 2.5min involving FePc and N, N-dimethylformamide in the presence of GO. According to the synthesis mechanism revealed by this study, carbon monoxide acts as a strong linker between the single Fe atoms and graphene. It facilitates the formation of a structure containing oxygen species between FeN4 and graphene, which provides high activity and stability for the ORR. These catalysts possess an enormous number of active sites and exhibit enhanced activity toward the alkaline ORR. They demonstrate excellent performance when applied to real electrochemical devices, such as zinc-air batteries and anion exchange membrane fuel cells. It is expected that the instantaneous heat treatment method developed in this study will aid in the development of high-performing single-atom catalysts.

Microstructure and Properties Evolution of 7075 Al alloy in Hot Rolling and Short Process Heat Treatment

7075 aluminum alloy is widely used in the aerospace field because of its low density, high specific strength, high fracture toughness, and good machinability. This paper systematically studied the evolution of the microstructure and properties of 7075 aluminum alloy at different temperatures. Based on the rolling and heat treatment process, a short process of rolling and heat treatment is proposed, which can significantly improve the properties. The study found that the nano‐phases were distributed in a “streamline‐like” or “lip‐like” shape after rolling. When the rolling temperature was below 550°C, the phases were mainly Al7Cu2Fe, the grain size did not change significantly, and shear bands appeared inside the grains. When rolled at 600°C, the grains coarsened significantly and the shear bands became longer, resulting in overburning and cracking. The broken phases were smoothed when rolled at 550°C. It was observed that the nano‐phases became larger. Due to the strain‐strengthening effect, the UTS increase by 6% with little change in elongation. In industrial production, direct aging treatment after high‐temperature rolling can reduce energy consumption and improve production efficiency.This article is protected by copyright. All rights reserved.

Erratum to “Effect of short heat treatment on mechanical properties and shape memory properties of Cu–Al–Ni shape memory alloy”

Erratum to “Effect of short heat treatment on mechanical properties and shape memory properties of Cu–Al–Ni shape memory alloy”

Effect of short heat treatment on mechanical properties and shape memory properties of Cu–Al–Ni shape memory alloy

Abstract The transformation of shape-memory alloys to high-temperature shape-memory alloys can be achieved through either the addition of alloying elements or heat treatment. However, heat treatment is more effective in improving the properties of the alloys. This research paper explores the impact of annealing on the mechanical and shape memory properties of Cu–Al–Ni shape memory alloys. The alloys were first cast, homogenized, and then machined before being aged at temperatures of 250, 300, and 350°C, and finally air-cooled. The results showed an increase in transformation temperature and recovery strain, as well as shape memory effect, and a decrease in hardness. Moreover, there was an increase in yield stress and strain. In conclusion, aging was found to improve the shape memory properties and mechanical properties better than thermomechanical treatment and some alloying elements.

Effect of Short Heat Treatments on the Microstructural Evolution and Hardness of Thixoformed Graphene Reinforced Aluminium Composites

Aluminium metal matrix composites are increasingly being used in numerous industries due to their lightweight nature and high strength. The incorporation of graphene into aluminium metal matrix composites has garnered significant interest owing to graphene's capacity to enhance numerous properties concurrently. Hence, this study aimed to fabricate a 0.3 wt.% graphene nanoplatelets reinforced A356 alloy (GNP-A356) composite through stir casting followed by thixoforming and short T6 heat treatment processes. It also evaluated the microstructure and mechanical properties of GNP-A356 after the thixoforming process and short T6 heat treatment. The microstructure of alloy and composite was confirmed by optical microstructure, field emission scanning electron microscopy images, and X-ray diffraction. Microstructure investigations demonstrate the impact of the stirring process on the structural transformation of the 𝛼-Al phase from the dendritic into a rosette-like and globular-like structure. The result also indicated that there was a transformation of eutectic silicon from the shape of a needle-like to spheroid structure after a short heat treatment, showing the efficiency of T6 heat treatment with a shorter time of solution treatment and ageing. Moreover, the increase in relative density and addition of reinforcement led to a significant increment in hardness. The result shows the hardness improved by 35.77% and 77.8% for as-cast and heat-treated composites, respectively, compared to A356 alloy.

Precipitation and reverted austenite formation in maraging 350 steel: Competition or cooperation?

Aged maraging steels offer unique strength and toughness via the presence of finely dispersed precipitates, allowing the material to reach values of up to 2400 MPa in yield strength in the case of 18Ni350. However, when aging heat treatments above 550 °C are conducted, simultaneous precipitation and austenite reversion can occur changing the mechanical behavior of the material. Although many studies related to the physical metallurgy of maraging steels have already been published, less attention has been given to a detailed understanding of the initial formation of austenite and its relationship with the precipitates. In this study, undeformed and cold rolled commercial 18Ni350 maraging steel samples were submitted to short aging heat treatments of 1800s at 600, 650, and 700 °C. The influence of the initial microstructure on subsequent phase evolution was studied using in-situ synchrotron X-ray diffraction and final microstructural products using transmission electron microscopy and atom probe tomography. Results show that cold rolled samples did not present faster kinetics of transformation of reverted austenite as expected, but this condition presented austenite in a different morphology than the undeformed condition. However, cold rolling changed the morphology of reverted austenite from elongated (undeformed case) to equiaxed; and induced a higher density of smaller Ni3Ti and Fe2Mo precipitates, especially after low-temperature aging. Besides, the deformation extinguished retained austenite, which influenced the reverted austenite formation, concluding that the simple increase in dislocation density is not a unique and direct factor to increase the reverted austenite kinetics.

Effect of Short Heat Treatment of Amorphous Metal Alloy on Decolorization Dye Mendola Blue

Effect of Short Heat Treatment of Amorphous Metal Alloy on Decolorization Dye Mendola Blue

Facile preparation of durable superhydrophobic coating with microstructure self-repairing function by spraying method

Self-healing superhydrophobic coatings have attracted tremendous attention recently, although their practical applications are severely limited by hydrophobic instability and poor structure durability. In this study, a durable superhydrophobic coating was fabricated by a rapid micro/nano structural reconstruction strategy. Carbon nanofibers (CNF) with high aspect ratio were interspersed in fluorosilicone resin (FSR) to construct a uniform network structure. By combining with temperature-responsive carnauba wax (CW) and modified fluororubber (MFR), we obtained a superhydrophobic FSR/CNF/CW/MFR coating with a water contact angle (WCA) of 157 ± 1.2° and water sliding angle (WSA) of 4.5 ± 0.4°. Under the triple synergy of polymer segment migration of FSR, temperature-responsive phase transition of CW, and elastomer rebound repair of MFR, the damaged FSR/CNF/CW/MFR coating surface was rapidly reformed to a new hierarchical micro/nanostructure with short heat treatment (less than 120 s). As a result, for a flat surface, after 1000 abrasion cycles or falling ball impact, a rich micro/nano structure was rapidly reconstructed and superhydrophobic properties were restored. The reconstructed micro/nano multistage structure could effectively capture air, which led to the repaired area exhibiting a charming silver mirror effect and excellent self-cleaning performance. Therefore, this work is expected to provide new insight into the restoration of micro/nanostructures of durable superhydrophobic coatings.

High temperature AlN thin film ultrasonic transducers with dual mode wave excitation

AlN thin film ultrasonic transducers with dual mode wave (transverse and longitudinal) excitation were deposited by reactive RF magnetron sputtering technique. The transducers deposited at radial distances of 0 and 50 mm in the sample plane exhibited well-developed straight and inclined columnar structures with dominating (002) and (103) X-ray diffraction peaks, respectively. The transducers deposited at radial distances of 0, 30, and 50 mm demonstrated excitation of longitudinal, transverse, and longitudinal-transverse waves, respectively. Short term heat treatment was conducted in air within a temperature range of 20–900 °C to investigate the high temperature ultrasonic response. Temperature dependencies of the time-of-flight and pulse-echo amplitude were analyzed. Long term heat treatment in air at 700 °C for 192 h revealed a degradation of ultrasonic response due to the oxidation of the AlN layer.

Downsizing FeNb11O29 anode material through ultrafast solid-state microwave-assisted synthesis for enhanced electrochemical performance

Wadsley-Roth oxide FeNb11O29 powder samples are successfully prepared using a simple, cost-effective, and ultrafast microwave-assisted solid-state synthesis for the first time. While conventional solid-state route in furnace requires hours of high-temperature treatment, both monoclinic and orthorhombic polymorphs of FeNb11O29 were obtained in minutes under microwave heating. Combining such short heat treatment with submicrometric oxide precursors enables to limit particle growth during the synthesis. The electrochemical benchmark clearly shows that FeNb11O29 powder samples obtained rapidly from submicrometric oxide precursors exhibit enhanced cycling performance. For example, the monoclinic polymorph prepared in only 5 min offers a high capacity of 179 mAh g-1 (90 % retention) after 500 cycles at 2 A g-1, approximately 20 % more than with conventional synthesis protocol. Electrochemical analysis demonstrates that the extra capacity is gained at low voltage and is probably induced by an easier ionic diffusion occurring in smaller particles. This work confirms the interest of solid-state microwave heating to design of electrode materials with limited particle growth and better cycling performance.

Twin-Roll Casting as a Grain Refinement Method and Its Influence on the Microstructure and Deformation Behavior of an AZ31 Magnesium Alloy Wire

Due to a combination of casting and rolling in one process step, twin-roll casting is an effective grain refinement method. This study compares the direct-chill cast (DC) state and the twin-roll cast (TRC) state of an AZ31 magnesium alloy in different steps regarding the microstructure, deformation behavior, and mechanical properties. In the initial state, the TRC AZ31 exhibits a significantly finer grain size and a slight rolling texture compared to the DC AZ31. Therefore, the TRC materials exhibit higher strengths and ductility. After a short heat treatment of 400 °C and 12 h for the DC state and 460 °C and 15 min for the TRC state, cylindric compression tests of the heat-treated samples were conducted at different temperatures (300–400 °C) and strain rates (0.1–10 s−1). To reproduce the deformation behavior at higher strain rates, hot rolling tests (350 °C, 15 s−1) of the heat-treated samples were performed. For both alloys, discontinuous dynamic recrystallization and twinning-induced dynamical recrystallization could be detected. A fine grain size and similar strengths were present after five passes. The AZ31 TRC exhibited a higher ductility due to a higher texture intensity, as the stress direction corresponds to the rolling direction in the case of tensile testing.

Microstructural Evolution and Room Temperature Mechanical Properties in Additively Manufactured Mar M 509 With Short Cycle Heat Treatment

Abstract The Co-based superalloy Mar M 509, known for its high-temperature oxidation and hot corrosion resistance, is processed via laser powder bed fusion (LPBF). Microstructure and mechanical properties of Mar M 509 in as-printed (As-P) and heat-treated (HT) states are compared based on two build orientations (longitudinal (L) and transverse (T)) to establish structure-property links with heat treatment. The As-P condition displays a distinct cellular microstructure (500–600 nm) with 50–60 nm carbide particles adorning cell boundaries. Longitudinal (L) build has columnar grains (8–35 μm along the major axis) with a grain aspect ratio of 4, while transverse (T) orientation exhibits equiaxed, bimodal microstructure (5–10 μm and 15–25 μm grain sizes). Strong <001> texture is noted in L. Mechanical properties at room temperature differ between L and T; T (569 ± 12 HV) has 15% higher hardness compared to L (489 ± 18 HV) and 34% higher 0.2% yield strength (YS), but 30% lower elongation than L. Post a short heat treatment cycle at 1250 °C, weld bead structure and cell boundaries break down. Both L (25–33 μm along the major axis) and T orientations (5–42 μm) experience grain growth, and carbides coarsen (250–350 nm). Post-heat treatment, dislocation density decreases, indicating recrystallization; lattice parameter of matrix reduces, implying solute depletion contributing to carbide enrichment. Yield strength drops from 860 MPa to 740 MPa in L and from 1150 MPa to 840 MPa in T, with ductility rising from 14% to 23% in L.

Structural and functional analyses of Pcal_0917, an α-glucosidase from hyperthermophilic archaeon Pyrobaculum calidifontis

Genome analysis of Pyrobaculum calidifontis revealed the presence of α-glucosidase (Pcal_0917) gene. Structural analysis affirmed the presence of signature sequences of Type II α-glucosidases in Pcal_0917. We have heterologously expressed the gene and produced recombinant Pcal_0917 in Escherichia coli. Biochemical characteristics of the recombinant enzyme resembled to that of Type I α-glucosidases, instead of Type II. Recombinant Pcal_0917 existed in a tetrameric form in solution and displayed highest activity at 95 °C and pH 6.0, independent of any metal ions. A short heat-treatment at 90 °C resulted in a 35 % increase in enzyme activity. A slight structural shift was observed by CD spectrometry at this temperature. Half-life of the enzyme was >7 h at 90 °C. Pcal_0917 exhibited apparent Vmax values of 1190 ± 5 and 3.9 ± 0.1 U/mg against p-nitrophenyl α-D-glucopyranoside and maltose, respectively. To the best of our knowledge, Pcal_0917 displayed the highest ever reported p-nitrophenyl α-D-glucopyranosidase activity among the characterized counterparts. Moreover, Pcal_0917 displayed transglycosylation activity in addition to α-glucosidase activity. Furthermore, in combination with α-amylase, Pcal_0917 was capable of producing glucose syrup from starch with >40 % glucose content. These properties make Pcal_0917 a potential candidate for starch hydrolyzing industry.

Numerical Simulation of Carbon Redistribution during Steel Composite Production

During heat treatment of cladded steel composites, element redistribution may occur between the various plating materials. Depending on alloy composition and the particular time–temperature profile, Carbon (C) diffusion between the plating materials is observed. Herein, C diffusion between different layers of roll‐cladded steel composites during typical production routes is numerically simulated with the thermokinetic software package MatCalc. Two material combinations, 340LA–22MnB5 and 340LA–34MnB5, are compared with experimental results of large‐scale manufactured steel composite material at different production steps, from hot strip to hardened cold strip material. The simulation agrees qualitatively and quantitatively well with the experimental results. It is demonstrated that even short heat treatment intervals can have significant influence on the C redistribution within the steel composite.

Intermetallic compound and martensitic transformation in Ag/Cu co-modified Ti6Al4V alloy

Titanium and its alloys are promising materials for engine production, special pump manufacturing, and bone implants. However, the abrasion resistance and fracture toughness of Ti alloys are insufficient to withstand extreme high loading conditions and harsh environments. Surface modification is an effective way to improve the performance of Ti alloys. In this study, Ag and Cu were added to Ti6Al4V alloy through friction stir processing to modify its surface. The different ratios of the Ag/Cu powder mixture were designed to optimize the surface modification of Ti6Al4V, and the relationship between intermetallic compounds and martensitic transformation was analyzed. The martensitic transformation was induced by AgCuTi phases. The submicron-size martensite was distributed outside the AgCuTi particle, while the nano-laminar martensitic band was generated inside the AgCuTi particle. Under the co-modification of Ti alloy using Ag and Cu, the surface of Ti6Al4V alloy exhibited higher hardness (4.3 GPa) values and lower modulus (100.6 GPa), which gave the credit to the formation of AgCuTi and martensitic transformation. The alloy specimen was subjected to short heat treatment at 600 °C for 30 min to further modify the gradient structure. After the short heat treatment of the Ag/Cu co-modified specimen, a lower modulus (88.8 GPa) and a high level of hardness (4.1 GPa) were achieved. In addition, superelastic strain recovery was also enhanced, showing the further induced martensitic transformation. This work provides new insight into the surface modification of titanium alloys using the FSP method to achieve the ideal hardness and elastic modulus balance.

Grain size refinement and enhanced precipitation strengthening in a hot extruded 6xxx Al alloy without homogenization

Long duration homogenization treatment (HT) plays an essential role in the fabrication of wrought Al alloys. Although it consumes huge amount of energy, its necessity has seldom been suspected. In our work, homogenization treatments with various holding times were conducted on an Al-Mg-Si-Cu alloy, followed by hot extrusion, short solution heat treatment and final aging. It is interesting to report the alloy with no HT showed the highest strength. This is partly due to the formation of fine sub-micron α-AlFeMnSi dispersoids during homogenization. The dispersoids occupies the Si content that should be used to form the MgSi-rich nanoprecipitates, resulting in a decrease in the volume fraction of the nanoprecipitates. On the other hand, the transformation of the micro-sized α-AlFeMnSi constituent phase into fine dispersoids during HT reduced the number of nucleation cites for dynamic recrystallization and the pinning effect on grain boundaries, and thus led to a significant coarsening of the extruded grains. The alloy without HT thus contained both fine grains and high-density nanoprecipitates, which provided effective hindrance to dislocation sliding and led to a tensile strength of 434 ± 14 MPa, which is 21% higher than that of same alloy with 24 h HT. Our findings provide some deep insights into simplified processing and energy conservation during fabrication of high-performance Al alloys.