Low Melting Temperature Research Articles

The Effects of Microcrystalline Cellulose Addition on the Properties of Wood-PLA Filaments for 3D Printing.

This paper describes the use of microcrystalline cellulose (MCC) as an additive in wood-polylactic acid (PLA) filaments suitable for 3D printing. Filaments prepared with PLA, thermally modified (TM) wood, and three different MCC loadings (1, 3, and 5 wt%) by two-step melt blending in the extruder were characterized with respect to their rheological, thermal, and mechanical response. The analyses demonstrate that a low MCC content (1%) improves the mobility of the polymer chains and contributes to a higher elasticity of the matrix chain, a higher crystallinity, a lower glass transition temperature (by 1.66 °C), and a lower melting temperature (by 1.31 °C) and leads to a higher tensile strength (1.2%) and a higher modulus of elasticity (12.1%). Higher MCC loading hinders the mobility of the polymer matrix and leads to a rearrangement of the crystal lattice structure, resulting in a decrease in crystallinity. Scanning electron micrographs show that the cellulose is well distributed and dispersed in the PLA matrix, with some agglomeration occurring at higher MCC levels. The main objective of this study was to develop and evaluate a filament containing an optimal amount of MCC to improve compatibility between wood and PLA, optimize melt processability, and improve mechanical properties. It can be concluded that a 1% addition of MCC favorably changes the properties of the wood-PLA filaments, while a higher MCC content does not have this effect.

Laser Beam Welding Parametric Optimization for AZ31B and 6061-T6 Alloys: Residual Stress and Temperature Analysis Using a CCD, GA and ANN

Laser beam welding (LBW) is a technology that efficiently joins materials using a concentrated laser beam, providing advantages such as a small heat-affected zone (HAZ), high precision, adaptability to various materials, and seamless integration into automated processes. Precision in LBW is limited by challenges in selecting appropriate process parameters, performing expensive and risky physical experiments, and dealing with materials with high thermal conductivity and low melting temperatures, such as AZ31B and AA6061. This study aims to predict laser welding process parameters, encompassing beam power (4000W-6000W), spot size (0.4mm-0.8mm), welding speed (30mm/s-50mm/s), and segment number (5-15) utilizing the Response Surface Methodology (RSM), Genetic Algorithm (GA) and backpropagation neural networks. Beam power significantly affects peak temperature, leading to deeper laser penetration and a higher maximum temperature, while the segment number plays a crucial role in residual stress by potentially causing uneven cooling and distinct thermal gradients. The ANN results confirm the model's accuracy and the GA-predicted process parameters include a laser power of 4000W, welding speed of 50mm/s, spot size of 0.6mm, segment number of 15, peak temperature range of 888.9°C to 1020.5°C, and a preferred equivalent stress of 1396.62 MPa.

Golden Plasmophores with Tunable Photoluminescence and Outstanding Thermal and Photothermal Stability

AbstractAmong various hybrid nanomaterials, the combination of plasmonic nanoparticles and fluorophores in a single multifunctional nanoplatform, so‐called plasmophores, has attracted significant attention in different fields such as dark field, fluorescence, and photoacoustic imaging, biosensing, photothermal, and photodynamic therapy. Herein, author report a facile and controlled synthesis route of hybrid nanoplatforms composed of fluorescent gold nanoclusters (GNCs) coupled to plasmonic gold nanorods (GNRs) using controlled silica (SiO2) dielectric spacers of different thicknesses from now on referred to as GNR@SiO2@GNC plasmophores. The results show different degrees of plasmon‐enhanced fluorescence of the GNCs in their plasmophore hybrid system when placed at different distances from the plasmonic cores of the GNRs. On the other hand, these plasmophores show enhanced thermal stability compared to GNRs@CTAB (CTAB, cetyl trimethyl ammonium bromide). This results also demonstrated that upon annealing at elevated temperatures (800–1000 °C), the GNRs in the plasmophores are more thermally stable and robust than the GNRs@CTAB. More surprisingly, despite the commonly reported very low melting temperature of smaller‐size nanocrystals, the GNCs in the plasmophores showed high thermal stability and do not exhibit significant structural changes at elevated temperatures (800–1000 °C).

Construction and mechanism analysis of flame-retardant, energy-storage and transparent bio-based composites based on natural cellulose template

With the proposal of sustainable development strategy, bio-based energy storage transparent wood (TW) has shown broad application value in green buildings, cold chain transportation, and optoelectronic device fields. However, its application in most fields is limited due to its own flammability. In this study, epoxy resin, triethyl phosphate (TEP) and polyethylene glycol (PEG) were introduced into delignified balsa wood template by vacuum pressure impregnation, and bio-based TW/PEG/TEP integrating flame retardant, high strength and phase-change energy-storage performance was prepared. TW/PEG composites have no leakage during phase change process and their transparency is up to 95 %. Compared with TW/PEG, the shielding effect of char layer and the inhibition effect in condensed and gas phase significantly decrease the total heat release of TW/PEG/TEP. TW/PEG/TEP biocomposites still maintained a high enthalpy of phase change and a low peak melting temperature, which was conducive to its application around the area of low temperature phase change energy storage. In addition, the tensile strength of TW/PEG/TEP was nearly 4 times higher than that of DW, and its toughness was obviously enhanced. TW/PEG/TEP biocomposites conformed to the current concept of energy-saving and green development. It has the potential to replace traditional petrochemical-based materials and shows excellent application prospects in emerging fields.

Lead-Free Conductors with a Surface Treatment Ensuring a Low Melting Temperature

In order to protect the environment and to ensure sustainability, it is prohibited to use lead materials in the production of automotive components. As part of soldering, busbars are used that usually have a copper core and a coating made of tin, but the melting point of such material is high, which poses a problem during soldering. This article discusses the case where a busbar is interconnected with another conductor in a sealable pressure vessel where high temperatures and pressures are reached. The product is heated to a certain temperature and the melting temperature of the given bus coating is exceeded, resulting in soldering and an ideal connection of the wires. The problem is that the temperatures reached by the processor during this operation are lower than the melting temperatures of the busbar with a tin coating. In the article, the authors focus on the production and development of new types of busbars with a coating consisting of tin, bismuth and indium and discuss possible formulations and their effect on the melting temperature of the busbars.

The Photocatalytic Activity of the Bi2O3-B2O3-ZnO-TiO2 Glass Coating

Due to the low melting temperature, the glazes based on the Bi2O3-B2O3-ZnO system are used as coatings on the surface of industrial glass substrates. Moreover, the composition of these coatings does not contain PbO, meeting the optical and environmental properties requirements. In this study, TiO2 was used in the Bi2O3-B2O3-ZnO glaze system to improve its photocatalytic ability. This can be considered a four – component glass system Bi2O3-B2O3-ZnO-TiO2. The heating microscopy results show that the melting temperature of the glaze system is 606 °C. The Fourier transform infrared spectroscopy results show that the TiO2 polyhedra are located independently in the structure without participating in forming a glass network. Thanks to that, the photocatalytic properties of TiO2 are maintained. The X-ray diffraction patterns results show that the formed TiO2 nanocrystals are rutile and anatase crystals. The results of determining the band gap energy using UV-Vis show that the band gap energy of the base glaze system increases with the addition of TiO2. The methylene blue decomposition results also showed that the ability to decompose organic increased when TiO2 was added to the glaze coating. The characteristics such as melting temperature, microstructure, and photocatalytic capacity of Bi2O3-B2O3-ZnO-TiO2 white glazes (5 and 10 % weight of TiO2) also were indicated in this paper.

The effect of Te-based lead-free glass powder containing Ge and Ag+ on the contact formation and electrical performance of silicon solar cells

The Te-based glass powder exhibits distinctive characteristics such as a low melting temperature and high chemical stability, rendering it a focal point of research in the realm of glass powder applications for solar cells. In this investigation, a pioneering Ge-containing Te-based lead-free glass powder was synthesized, and the influence of GeO2 content on critical parameters such as glass transition temperature (Tg), high-temperature fluidity, high-temperature wettability, acid and alkali resistance, as well as the network structure of the glass, was systematically explored. At an optimal GeO2 content of 8%, the glass powder displayed the lowest Tg (437°C), accompanied by a subdued crystallization reaction. The high-temperature fluidity and wettability exhibited favorable characteristics, indicating that the inclusion of GeO2 in the glass powder resulted in an enhanced interface contact. Building upon this foundation, techniques to augment the Ag+ content within the glass powder were investigated, along with the interaction between Ag+ and the SiNx anti-reflection layer or silicon on the surface of crystalline silicon solar cells. It was discerned that the Ag+ content in the glass powder significantly influences the deposition of silver microcrystals on the surface of crystalline silicon, thereby impacting the contact resistance of the solar cell. Then influences the series resistance and photoelectric conversion efficiency of the solar cell.

A Surface Imprinted Polymer EIS Sensor for Detecting Alpha-Synuclein, a Parkinson's Disease Biomarker.

Parkinson's Disease (PD) is a debilitating neurodegenerative disease, causing loss of motor function and, in some instances, cognitive decline and dementia in those affected. The quality of life can be improved, and disease progression delayed through early interventions. However, current methods of confirming a PD diagnosis are extremely invasive. This prevents their use as a screening tool for the early onset stages of PD. We propose a surface imprinted polymer (SIP) electroimpedance spectroscopy (EIS) biosensor for detecting α-Synuclein (αSyn) and its aggregates, a biomarker that appears in saliva and blood during the early stages of PD as the blood-brain barrier degrades. The surface imprinted polymer stamp is fabricated by low-temperature melt stamping polycaprolactone (PCL) on interdigitated EIS electrodes. The result is a low-cost, small-footprint biosensor that is highly suitable for non-invasive monitoring of the disease biomarker. The sensors were tested with αSyn dilutions in deionized water and in constant ionic concentration matrix solutions with decreasing concentrations of αSyn to remove the background effects of concentration. The device response confirmed the specificity of these devices to the target protein of monomeric αSyn. The sensor limit of detection was measured to be 5 pg/L, and its linear detection range was 5 pg/L-5 µg/L. This covers the physiological range of αSyn in saliva and makes this a highly promising method of quantifying αSyn monomers for PD patients in the future. The SIP surface was regenerated, and the sensor was reused to demonstrate its capability for repeat sensing as a potential continuous monitoring tool for the disease biomarker.

Taurine, a Naturally Occurring Amino Acid, as a Physical Stability Enhancer of Different Monoclonal Antibodies.

Degradation of therapeutic monoclonal antibodies (mAbs) is a major concern as it affects efficacy, shelf-life, and safety of the product. Taurine, a naturally occurring amino acid, is investigated in this study as a potential mAb stabilizer with an extensive analytical characterization to monitor product degradation. Forced degradation of trastuzumab biosimilar (mAb1)-containing samples by thermal stress for 30min resulted in high-molecular-weight species by more than 65% in sample without taurine compared to the sample with taurine. Samples containing mAb1 without taurine also resulted in higher Z-average diameter, altered protein structure, higher hydrophobicity, and lower melting temperature compared to samples with taurine. The stabilizing effect of taurine was retained at different mAb and taurine concentrations, time, temperatures, and buffers, and at the presence of polysorbate 80 (PS80). Even the lowest taurine concentration (10mM) considered in this study, which is in the range of taurine levels in amino acid injections, resulted in enhanced mAb stability. Taurine-containing samples resulted in 90% less hemolysis than samples containing PS80. Additionally, mAb in the presence of taurine showed enhanced stability upon subjecting to stress with light of 365nm wavelength, combination of light and H2O2, and combination of Fe2+ and H2O2, as samples containing mAb without taurine resulted in increased degradation products by more than 50% compared to samples with taurine upon subjecting to these stresses for 60min. In conclusion, the presence of taurine enhanced physical stability of mAb by preventing aggregate formation, and the industry can consider it as a new mAb stabilizer.

Melt-quenched carboxylate metal–organic framework glasses

Although carboxylate-based frameworks are commonly used architectures in metal-organic frameworks (MOFs), liquid/glass MOFs have thus far mainly been obtained from azole- or weakly coordinating ligand-based frameworks. This is because strong coordination bonds of carboxylate ligands to metals block the thermal vitrification pathways of carboxylate-based MOFs. In this study, we present the example of carboxylate-based melt-quenched MOF glasses comprising Mg2+ or Mn2+ with an aliphatic carboxylate ligand, adipate. These MOFs have a low melting temperature (Tm) of 284 °C and 238 °C, respectively, compared to zeolitic-imidazolate framework (ZIF) glasses, and superior mechanical properties in terms of hardness and elastic modulus. The low Tm may be attributed to the flexibility and low symmetry of the aliphatic carboxylate ligand, which raises the entropy of fusion (ΔSfus), and the lack of crystal field stabilization energy on metal ions, reducing enthalpy of fusion (ΔHfus). This research will serve as a cornerstone for the integration of numerous carboxylate-based MOFs into MOF glasses.

Power Cycling Reliability with Temperature Deviation of Pressureless Silver Sintered Joint for Silicon Carbide Power Module

SiC devices can enhance power conversion in electric vehicles. However, traditional soldering techniques are limited by their low melting temperatures. Therefore, we used pressureless Ag sintering to assemble a 1200 V/200 A SiC metal-oxide-semiconductor field-effect transistor power module and compared the long-term reliability, electrical properties, and driving performance of the module with those of a similar module assembled using the solder Sn-3.0Ag-0.5Cu (SAC305). To assess sinter joint reliability, we performed power cycling tests over two temperature ranges, 50–150°C and 50–175°C, for 15,000 cycles. Subsequently, we compared the breakdown voltage (BVDSS) and drain-source on-resistance (RDS(ON)) of the SiC power modules and performed cross-sectional analyses of the device bonding interfaces. No difference in BVDSS was found between the Ag-sintered and SAC305-soldered joints. However, the RDS(ON) exhibited minimal variation for the Ag-sintered module but significantly varied for the SAC305-soldered module, suggesting that the former better maintained its characteristics. Furthermore, the electrical characteristics of the SAC305-soldered module underwent more significant alterations with increasing temperature change during power cycling, indicating that cracks propagated throughout the SAC305 soldered joint over time. Therefore, Ag sintering was quantitatively validated as the superior die attachment technology compared to soldering for long-term reliability.

RELATIONSHIP OF LEAD WITH FREE RADICALS, REACTIVE OXYGEN SPECIES, OXIDATIVE STRESS AND ANTIOXIDANT ENZYMES

Heavy metals, which are high in the environment, are substances that have a high toxic effect even at low concentrations. Heavy metals taken into the organism through mouth, respiration and skin cannot be eliminated by the body's excretory pathways. In addition, since they have a durable structure, they participate in the food chain and accumulate in various body tissues. With the increase in industrial activities, heavy metal pollution has also emerged and has increased day by day. Lead is an element that is widely used in industry because it has a low melting temperature. However, it is known that lead, like other heavy metals, has an effect on problems such as environmental pollution and health problems. Occupational diseases such as lead poisoning occur as a result of direct exposure to lead. Direct exposure in this way can also cause death. Lead causes undesirable conditions such as increase of reactive oxygen species (ROS), emergence of oxidative stress and weakening of antioxidant system. Lead disrupts the prooxidant/antioxidant ratio. As a result, effects such as an increase in ROS and thus damage to the basic components of the cell such as lipid, protein and nucleic acid are observed.In particular, lead inhibits enzymes and prevents some enzymes from acting as antioxidants. As a result of exposure to lead, there is a decrease in the defense abilities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) and ascorbic acid in blood and tissues. Lead increases lipid peroxidation and thus causes oxidative damage. Evaluation of the effect of lead at the cellular level is important in terms of developing solutions for the toxic effects of lead. In this study, the effect of lead on the cellular level in the organism and its effects on free radicals, ROS and oxidative stress were evaluated.

Polyetheramine‐Type Semi‐Biobased Long‐Chain Polyamide 1210 Elastomer: Synthesis, Structure, and Unique Thermal Behavior

AbstractBiobased thermoplastic polyamide elastomers (TPAEs) have received increasing attention in both academia and industry. Here, a series of semi‐biobased long‐chain TPAEs are successfully synthesized via one‐step melt polymerization, employing polyamide 1210 (PA1210) and polyetheramines (PEAs) as hard and soft segments, respectively. The prepared TPAEs demonstrate excellent mechanical properties, energy dissipation capabilities, low density, good damping, high resilience, and low melting temperature. More interestingly, the properties of the TPAEs can be customized by adjusting the content and molecular weight of PEA. By varying the molecular weights of the PEAs, two different thermal behaviors can be observed in the prepared TPAEs. Specifically, PEA with low molecular weight has good compatibility with PA1210, leading to an increase in the conformation of the crystalline region and a significant decrease in melting temperature. Meanwhile, high molecular weight PEA causes strong phase separation with PA1210, leading to limited crystalline regions and inadequate physical cross‐linking, further resulting in suboptimal mechanical properties. This work provides new insights into the design and preparation of PEA‐type biobased long‐chain TPAEs.

Improved performance of kesterite Cu2ZnSn(S,Se)4 thin film solar cells by Ag/Ge co-doping

Cation doping is an important approach to improve the performance of kesterite Cu2ZnSn(S,Se)4 (CZTSSe) thin film solar cells. Since different cation dopant has different effects on the defects and crystallization of CZTSSe absorber, it is expected to achieve better device performance via the synergistic effects of double cation co-doping compared with the single cation doping. Herein, we investigated the effects of Ag/Ge co-doping on CZTSSe solar cells by doping Ge in an already optimized Ag-alloyed CZTSSe (ACZTSSe). It is found that incorporating a small amount of Ge can further improve the crystallinity and minority carrier lifetime of ACZTSSe. The low-temperature photoluminescence results reveal that the Ge doping primarily suppressed the SnZn defects in ACZTSSe, thereby further boosting the device performance. However, higher Ge doping concentration can lead to a discontinuous surface morphology, which is believed to be related with the relatively low melting temperature and double-layered structure of ACZTSSe absorber. The deteriorated surface morphology results in photocurrent loss in the near-infrared region and decreased fill factor. As the Ge doping ratio increases, there is a balance between the defects and morphology. A champion power conversion efficiency (PCE), 11.4%, was achieved for the Ag/Ge co-doped CZTSSe solar cells at Ge substitution rate of 3%. Compared with the single Ag doping, the average PCE was further promoted by 0.5% due to Ag/Ge co-doping.

Improved melting temperature predictions for single LNA modifications in synthetic DNA oligonucleotides

Locked nucleic acids (LNA) is a modification to DNA that generally increases the melting temperature in double strands. The nearest-neighbour (NN) provides one of the best prediction accuracies and is attractive for its simplicity. Here, we revise the NN parametrization for single LNA modifications with a very large set of published melting temperatures and using a parameter optimization method especially aimed at accurate melting temperature predictions. We show that the new set of LNA-NN parameters achieves an improved prediction of 0.88 °C over older parameter sets that achieve 1.7 °C for this data. We also tested if the existing salt corrections for DNA could be used for LNA as well. Using a small set of low salt melting temperatures we show that by applying the usual DNA salt corrections one may obtain predictions within an average uncertainty of 3.0 °C.

Late Paleozoic magmatism from northern Sibumasu terrane: Constraints on separation of Cimmeria from Gondwana

The Cimmerian is one of several continental terranes that separated from northern Gondwana during the Carboniferous-Permian period. Magmatic evidence for the rifting of the fragments from Gondwana is preserved in the Baoshan area of eastern Cimmeria. These magmatic rocks outcrop over an area of more than 10,000 km2 and are mainly composed of basalts and dolerites, with limited occurrences of picrites. Our new results show that the basalts are tholeiitic and exhibit enriched trends in light rare earth elements (LREE), negative anomalies in Nb-Ta-Ti, and enriched isotopic signatures in Sr-Nd-Pb. They underwent fractional crystallization of clinopyroxene and olivine, with insignificant crustal contamination. Suppositional primary melt compositions and REE modeling results suggest that they were mainly formed by 2–5 % degrees of melting of spinel lherzolites with minor garnet (<1%) in a shallow enriched EMII lithospheric mantle, with minor components from the depleted mantle. Lack of plume-related ocean island basalts, a narrow south-north distribution, and a relatively low melting temperature may contradict the plume model. The Woniusi basalts could have originated in a back-arc environment, but further research is required to gather a more complete spectrum of volcanic rocks associated with the arc. In contrast, we propose that they were formed on the lower-plate passive Gondwana margin after the northward subduction of the Paleo-Tethys Ocean since the Late Devonian. This subduction may result in a longer-lasting extension of the passive Gondwana margin. The Woniusi basalts are roughly coeval with the subduction of the mid-ocean ridge during the Latest Carboniferous. After the active ridge has subducted, the slab pull is strong enough to separate a terrane, because the ridge spreading no longer absorbs the strain caused by subduction. If this is the case, subduction of the Paleo-Tethys ocean-ridge would enhance slab-pull forces and finally trigger Woniusi magmatism.

Recent Progress on the Tribology of Pure/Doped Diamond-like Carbon Coatings and Ionic Liquids

This review provides a comprehensive overview of recent advances in tribology concerning pure/doped diamond-like carbon coatings (DLCs) and ionic liquid (ILs) interaction. DLC coatings are often used in industrial machinery and processes where sliding occurs between surfaces, leading to wear and degradation of their surfaces. DLC coatings are optimized by adjusting operating and deposition parameters as well as doping them with other elements to improve performance, such as thermal stability and chemical resistance. ILs are a promising green lubricant option due to their low melting temperature, superior thermal stability, and high miscibility with organic substances. ILs have been studied as neat lubricants and additives, and their tribological properties have been investigated, including their use as extreme temperature lubricants. The tribological properties of pure/doped DLC coatings with ILs have also been explored, although limited research has been conducted in this area. The combined effect of DLCs and ILs shows great promise in reducing energy loss due to friction, promoting longevity, and conserving energy.

Synthesis of High-Value Bio-Based Polyamide 12,36 Microcellular Foams with Excellent Dimensional Stability and Shape Recovery Properties.

The search for alternatives to petroleum-based thermoplastic polyamide elastomers (TPAEs) has recently drawn great interest. In this study, a bio-massed TPAE, PA12,36, was synthesized using 1,12-dodecanediamine (DDA) and fatty dimer acid (FDA, PripolTM1009) precursors via catalyst and solvent-free melt polycondensation. The molecular structure and molecular weight of the PA12,36 were characterized by 1H NMR, FTIR, and GPC. PA12,36 displayed a low melting temperature of 85.8 °C, an initial degradation temperature of 425 °C, and a glass-transition temperature of 30.4 °C, whereas it sustained satisfactory tensile strength (10.0 MPa) and superior strain at break (1378%). Furthermore, PA12,36 was foamed by supercritical CO2, and the cell size, cell density, and porosity were determined. The entangled long-chained FDA component generated a physically crosslinked network, which promoted the melt viscosity of PA12,36 against elongations of foam cell growth and increased foamability significantly. As a result, uniform structured cellular foams with a cell diameter of 15-24 µm and high cell density (1011 cells/cm3-1012 cells/cm3) were successfully achieved. The foaming window was widened from 76 to 81 °C, and the expansion ratio was increased from 4.8 to 9.6. Additionally, PA12,36 foam with a physically crosslinked structure presented a better creep shape recovery percentage (92-97.9%) and sturdier dimensional stability. This bio-based PA12,36 foam is a promising candidate to replace petroleum-based thermoplastic elastomer foams for engineering applications, particularly shoe soles.

The correlation of the liquidus curves and valence electron structures of a ternary lithium halide molten-salt electrolyte for liquid metal batteries.

Liquid metal batteries have received considerable attention owing to their excellent properties. However, an electrolyte with low melting temperature is required to decrease operating temperature for the safety of liquid metal batteries and for saving energy. For revealing the mechanism of low liquefaction temperature, an empirical electron theory of solid molecules was used to study the thermal properties of pure lithium halides and their ternary-phase systems systematically. The theoretical bond lengths, melting points, liquefaction temperatures and mixed energies of pure lithium halides and their ternary phases match the experimental values well. The mechanism of liquefaction temperature for ternary lithium halides depends on their valence electron structures. The liquefaction temperature can be stabilized on a liquidus line or curve through the modulation of the constant number of covalent electrons (nc) and lattice electrons (nl). The liquefaction temperatures on various liquidus lines and curves are positively related to the linear density of valence electron pairs on the strong Li-X bond, bonding factor, and number of valence electrons in the s orbital but are negatively related to the number of valence electrons in the p orbital. With an increase in the linear density of the valence electron pair number and bonding factor, bond strength is enhanced, which increases the resistance of the strong Li-X bond against the break force induced by thermal phonon vibrations, and more thermal phonons with high vibrating energy are required for breaking the strongest Li-X bond at a higher temperature; therefore, the liquefaction temperature increases.

Challenges and opportunities to develop the method of joining dissimilar material aluminium-steel by using Rotational Friction Welding (RFW)

The combination of the lightweight AL 6061 and high-strength steel SWRM 1008 is utilized by the industrial sector, including the automotive industry to make bumper reinforcement. The properties of AL 6061 and SWRM 1008 steel have specific differences so an appropriate welding method is needed. This is a challenge and an opportunity for its application in the future. Rotational friction welding (RFW) is one of several welding processes that can be applied to join AL 6061 with SWRM 1008 and furthermore, the welding is environmental. The occurrence of diffusion between AL 6061 and SWRM 1008 is influenced by the heating temperature and forging pressure. Due to different melting temperature the steel in this research has been preheated. Al 6061 has a lower melting temperature than SWRM 1008 and a male-female shape has been made so that excessive upset did not be overformed and the forging process ran optimally. The welding process used rotational friction welding between Al 6061 and SWRM 1008 with preheat temperature 3500C, rotational speed 800 rpm, friction pressure 2 Mpa, and forging pressure 3 Mpa. The results of the joining were then tested for tensile strength and micro-photos. The preheat to SWRM 1008 before the welding process causes softening of the aluminium surface immediately after contact. Excessive softening of the aluminium surface establishes an upset before diffusion occurs. IMC will form well under high shear stress and forging pressure. The welding process at low pressure obtained a connection tensile strength value of 65.2Mpa even though it had been preheated before welding took place. From this research, we can know if rotational friction welding gives opportunities to join the AL 6061 with SWRM1008.