Conventional Casting Technique Research Articles

Development of Eco‐Friendly Chitosan‐Dextran Polyblend Electrolyte for Enhanced Performance in Primary Magnesium Batteries

The potential of next‐generation batteries lies in solid biodegradable polymer electrolytes. This research delves into a solid blend polymer electrolyte (SBPE) for magnesium conduction, utilizing a chitosan‐dextran blend matrix doped with magnesium perchlorate (Mg(ClO4)2) salt. The electrolyte films are prepared using a conventional solution casting technique. Through techniques like X‐ray diffraction and Fourier transform infrared spectroscopy, the successful incorporation of Mg(ClO4)2 into the blend matrix is confirmed. Notably, the SBPE containing 30 wt% of Mg(ClO4)2 demonstrates the highest ionic conductivity of 6.99 × 10−4 S cm−1 and a prominent ionic transference number of 0.84. Thermogravimetric analysis is carried out to study thermal stability. Differential scanning calorimetry analysis of the electrolyte systems gives insight into their thermal properties. Additionally, it showcases favorable electrochemical stability of 2.66 V. The oxidation and reduction peaks are observed in the cyclic voltammetry curve of the highest conducting sample. Furthermore, the discharge performance of Mg/(CS + DN + Mg(ClO4)2)/cathode cells is explored with varied cathode materials, illustrating the SBPE's potential for magnesium‐ion batteries. This study unveils a sustainable, biodegradable, and economical electrolyte solution for advanced energy storage systems.

Synthesis and characterization of multi-walled carbon nanotube-reinforced Ti–Mg alloy prepared by mechanical alloying and microwave sintering

Titanium-magnesium (Ti–Mg) alloy is a widely accepted bimetallic material suitable for biomedical applications. However, reduced wear and corrosion resistance, low strength and hardness, and stress shielding effect limit their widespread applications. Reinforcing multi-walled carbon nanotubes (MWCNTs) possessing low density, high modulus, and improved mechanical properties overcome the shortcomings of Ti–Mg alloy. In the present work, nanostructured Ti–Mg alloy was synthesized at room temperature and simultaneously reinforced with MWCNTs. The high energetic ball milling process (HEBM) has been successfully utilized to mechanically alloy Ti with Mg at room temperature by decreasing the grain size to the nanoscale and reinforcing the alloy with MWCNTs. The synthesized nanostructured powder size was 25 nm. Characterization results have shown the emergence of new phases like Ti4C4 and Mg2C3 as a result of mechanical alloying (MA). The reinforced alloy powder was consolidated by cold compaction and followed by microwave sintering. The consolidated sample crystallite size attained was 72 nm and then characterized by Nanoindentation, XRD, and SEM. XRD results show intermetallic compounds Mg2C3 and TiC in bulk samples. SADP TEM confirmed the retention of Nano and partial amorphous structures in the consolidated samples. The nanoindentation test revealed the hardness and elastic modulus values 0.93 GPa and 28.12 GPa, respectively, equivalent to CpTi and its associated alloys. The results are prevalent in those alloys used in biomedical applications produced by conventional melting and casting techniques and can be a potential biomaterial.

Comparing the trueness of 3D printing and conventional casting for the fabrication of removable partial denture metal frameworks for patients with different palatal vault depths: An in vitro study

Statement of problemThe success of a removable partial denture depends on its fit, and, with conventional casting, the framework is more distorted in patients with a deep palatal vault. Questions remain about whether the three-dimensional (3D) printing technique for fabricating a framework can improve the accuracy of fit for these patients. PurposeThe purpose of this in vitro study was to compare the trueness of metal frameworks fabricated by selective laser melting, 3D printing pattern casting, and conventional casting for different palatal vault depths. Material and methodsA total of 30 partially edentulous maxillary casts were custom-made in 15 medium and 15 deep palatal vaults. All stone casts were scanned as reference models in digital files. For the medium palatal vault casts, Co-Cr frameworks of the conventional casting (CON) group (n=5) were fabricated with the lost wax technique. For the 3D printing pattern casting (PPC) group (n=5), wax patterns of the framework were printed, followed by metal casting. The frameworks created for the selective laser melting (SLM) group (n=5) were printed directly by using the SLM machine. The same procedures were followed for the deep palatal vault group. All the metal frameworks were scanned and superimposed with the reference casts by using the Geomagic Control X software program. Discrepancies were measured as mean ±standard deviation (trueness), and the data were statistically analyzed with a 2-way ANOVA test to evaluate the interaction of 2 independent factors (fabrication techniques and palatal vault depths) on a trueness outcome (α=.05). ResultsThe lowest mean ±standard deviation value was 0.092 ±0.023 mm, found from the SLM framework with deep palatal vault group, while the highest value was 0.194 ±0.017 mm, found from the CON framework with deep palatal vault group. Different fabrication techniques interacted with different palatal vault depths in terms of trueness (P<.05); however, no significant differences were observed in the medium palatal vault groups (P>.05). Additionally, color mapping demonstrated the gaps of metal frameworks among the 6 groups. ConclusionsWith the conventional casting technique, the accuracy of the metal framework was affected by the depth of the palate. For medium palatal vaults, all fabricated frameworks had clinically acceptable fit. For deep palatal vaults, the SLM frameworks showed the lowest discrepancy. As a result, the SLM technique is advised for fabricating a better-fitting metal framework for patients with a deep palatal vault.

PRODUCTION OF Ni-HARD ALLOY POWDERS BY GAS ATOMIZATION

Ni-Hard cast iron materials are frequently used in equipment where high wear resistance is required in industrial applications. Generally, Ni-Hard is produced by conventional casting techniques. In this study, it was aimed to produce Ni-Hard powders to produce Ni-Hard cast iron materials with additive manufacturing techniques. To produce spherical and fine raw materials for additive manufacturing techniques, the gas atomization technique with a close-coupled nozzle system was preferred for the production of Ni-Hard powders. Ni-Hard alloy was melted in a high-frequency 10kW induction furnace under a protective atmosphere integrated into the gas atomization system. During the atomization process, 150 °C superheating was applied to prevent the liquid metal from freezing and clogging the melt delivery tube. In terms of the continuity of the atomization process, the negative pressure (aspiration pressure) values formed at the end of the melt delivery tube at different gas pressures were measured. An aspiration pressure of -50 mbar was obtained under an atomization pressure of 35 bar. Particle size distributions, hall flow behaviour and angle of repose properties of the produced powders were determined. Finally, the characterization of the powders was carried out by scanning electron microscopy. It was determined that the powders obtained as a result of atomization exhibited a spherical morphology and a narrow size range. The Hall flow rate test result of Ni-Hard powders was measured as 22 seconds for 50 g.

Reinforcement of biodegradable SiO2NPs-modified cellulose-gelatin hydrogel films with antioxidant and antibacterial properties as potential food packaging composite

This study proposed an innovative approach to the development of sustainable and biodegradable food packaging materials by incorporating inexpensive nano-silica (SiO2NPs) in designed hydrogel (CSG) film employing biodegradable polymers: synthetic polymer polyvinyl alcohol (PVA), natural polymer - carboxymethyl cellulose (CMC) and protein-based bio-polymer –gelatine, and a commercial crosslinker, tetraethoxysilane (TEOS) through a conventional air-dry casting technique. The CSG hydrogel blends were modified with varying amounts of SiO2NPs (0.05g, 0.1g, 0.15g and 0.2g) and compared with the blend without SiO2NPs to determine the effect of SiO2NPs loading through various characterisation techniques and applications including antioxidant and antimicrobial activity. Comprehensive characterizations of the CSG films revealed that CSG 0.1 (containing 0.1g SiO2NPs) exhibited the most favourable functional properties, low crystallinity, high flexibility, suitable pore size, thermal stability, adequate tensile strength, elongation at the breaking point and maximum stability by swelling and diffusion test. The addition of SiO2NPs consistently enhanced thermal and mechanical stability in all CSG films. Further, these CSG films were implemented for antioxidant test and antimicrobial activity against gram-positive Bacillus cereus and gram-negative Escherichia coli. SiO2NPs integration significantly elevated the antioxidant capacity in all films, with CSG 0.1 showing ⁓7% improvement. The antimicrobial activity of SiO2NPs-modified CSG films was also notable, with CSG 0.1 effectively inhibiting B. cereus by 1.2cm zone and E. coli by 0.5cm zone. A soil burial test was performed to pattern the biodegradability of CSG hydrogels. Therefore, the outstanding improvements in the intrinsic properties of CSG films, owing to SiO2NPs modification, positioned these CSG hydrogels as promising candidates for advanced food packaging materials in various industries.

Enhancing tribo-mechanical and corrosion properties of A383 aluminum matrix composites through stir-cum-squeeze casting with marble dust and hexagonal boron nitride reinforcement

The A383 aluminum matrix composites (AMCs) are prominent automotive materials owing to their low-density yet high-strength nature. However, the conventional casting techniques, exorbitant price, and scarce supply of traditional ceramic reinforcements remain challenging. This research countermeasure the challenges by hybridizing the A383 with industrial marble dust (MD) and hexagonal boron nitride (hBN) through the stir-cum-squeeze casting technique. A constant proportion (4 wt%) of MD waste and varying proportions of hBN (1.5, 3, 4.5, and 6 wt%) were used to reinforce A383 alloy to improve its physio-mechanical characteristics. Stir-cum-squeeze casting enables homogenous dispersion of reinforcement particles within the matrix, resulting in improved interfacial bonding. Optimal results were achieved for A383 alloy reinforced with 4 wt% of MD and 6 wt% hBN, ensuring balanced tribo-mechanical characteristics against the as-casted A383. The hardness value increased by 40.8%, while the compression and tensile strength increased by 30.8% and 115.8%, respectively. Non-destructive testing confirms the effective reduction of porosity in the stir-cum-squeeze-cast composites. Moreover, the hybrid composites exhibit improved corrosion resistance by 32.18% after 72 h of testing. Additionally, the hybrid composites demonstrate a wear rate reduction of 54.35%.

High-performance solid-state Li-ion batteries enabled by homogeneous, large-area ferroelectric PVDF-TrFE solid polymer electrolytes via horizontal centrifugal casting method

Solid polymer electrolytes (SPEs) have emerged as promising alternatives for enhancing the safety features of lithium-ion batteries (LIBs) while remaining compatible with established LIB manufacturing processes. However, a persistent challenge has been the relatively limited yield achieved via traditional fabrication techniques such as solution casting and doctor blade methods. In this study, we present a novel strategy to produce extensive and uniform films of solid polymer electrolytes using a ferroelectric polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) polymer. This approach employs horizontal centrifugal casting (HCC), a technique hitherto unutilized for SPE production. The substantial centrifugal forces generated during the HCC process yield SPE films characterized by uniform thickness across the surface and elevated ionic conductivity at ambient temperature. Compared to conventional solution casting techniques, the Li//Li cell featuring the SPE derived from HCC manifests stable electrochemical performance and increased cycle endurance. Additionally, a full cell incorporating a Li iron phosphate cathode displays consistent electrochemical behavior at room temperature. Notably, a 3 × 4 cm2 pouch cell maintains its performance attributes even under mechanical stress conditions such as folding and punching. These findings underscore the potential effectiveness of employing the HCC method in the development of high-performance SPE-based LIB systems.

Experimental characterization of a cost‐competitive tailor‐made HPFRC mix design for wide application in precast girder of roadway bridges

AbstractThis paper presents a comprehensive study on the development of a cost‐effective, high‐performance fiber reinforced concrete (HPFRC) for the construction of a 60 m‐span U‐girder roadway bridge without stirrups in the webs, meeting the design requirements of fck ≥ 100 MPa and the post‐cracking flexural strength fR3k ≈ 8–10 MPa. The main objective of this research is to develop a F5 workability class HPFRC that meets the specified design criteria without exceeding 2.5–3.0 times the cost of a C70/85. To achieve this goal, the concrete mix was obtained using 500 kg/m3 of cement and 50 kg/m3 of silica fume. This mix was investigated with nine different combinations of fibers and fiber contents, resulting that 80 kg/m3 of 4D‐fibers (lf = 60 mm) provided the optimal fR3k without compromising workability and cost. Subsequently, an extensive experimental campaign was conducted to cast the U‐girder following the conventional casting techniques involving casting prismatic samples, L‐shaped and rectangular‐shaped panels to represent different parts of the U‐girder. Innovative techniques were used to study the effect of different waiting times between concrete pours. Results from the testing of the prismatic specimens evidenced the need of stitching by means of a poker vibrator planes between successive concrete layers. Furthermore, the study of the panels evidenced that a waiting time of 90 min allows the HPFRC to achieve enough bending and compressive strength to bear internal vibration of the element without liquefying and, at the same time, avoiding cold joints. The results confirm the applicability of the developed HPFRC for the structural element under study following conventional casting techniques.

Experimental investigation of compressive behavior and vibration properties of layered hybrid foam formed by aluminum foam/EPS-filled syntactic foam

Hybrid foams are a type of composite material created by combining two foam materials. They are preferred in many applications due to their lightweight, high strength, and ability to absorb more energy. In this research, a new hybrid foam was designed for use in sandwich cores of structural materials. The hybrid foam was formed by combining closed-cell aluminum foam and expanded polystyrene (EPS)-filled syntactic foam. The EPS-filled syntactic foams were produced with the conventional mold casting technique. Uniaxial compressive behaviors (0.5 mm/min) of layered hybrid foams consisting of EPS-filled syntactic foam with three different densities and closed-cell aluminum foam were investigated experimentally and compared with conventional single-foamed materials. These results exhibited that in general, layered hybrid foams outperform conventional single-foamed materials in terms of compressive strength. Moreover, the natural frequency and damping ratio of the layered hybrid foams were investigated by vibration tests under clamped-free and free-free boundary conditions and compared to conventional single-foamed materials. It was established that the vibration damping capacity of the layered hybrid foams improved compared to the closed-cell aluminum foam. Additionally, the microstructure of the conventional single-foamed materials was examined by SEM. In the outcome of the research, the experimental results showed that layered hybrid foam provides an opportunity to design lightweight cellular materials with effective mechanical properties.

Novel approach to enhance the optical and electrical properties of polymer electrolytes using phenol red dye

AbstractThis article comprehensively analyzes how phenol red dye affects the optical, structural, and electrical properties of sodium bromide‐doped polymer electrolyte films based on sodium carboxymethyl cellulose. Conventional solution casting technique has been employed to prepare the electrolytes. The optical analysis reveals that incorporating the phenol red dye improves the optical properties. Fourier transform infrared spectroscopy is used to study the kind of complexation between the polymer and dopants. Scanning electron microscope micrographs of the electrolytes indicate the acquisition of free volume on the surface of the polymer matrix. The electrical properties are studied using impedance analyzer, which shows that the ionic conductivity increases when the dye is incorporated. The electrolyte system incorporated with 0.25 wt% of the dye exhibits the highest conductivity among the other systems. Photoluminescence investigation demonstrates that doping increases the intensity of the photoluminescence emission as it minimizes the free volume size. Commission Internationale de l'Eclairage (CIE) chromatograph studies indicate that the doped samples emit a yellow color with a color purity of 97%. All in all, the findings imply that adding dye to the polymer matrix increases the electrical and visual characteristics of the polymer electrolyte.Highlights Phenol red dye improves the optical properties of sodium carboxymethyl cellulose‐based polymer electrolytes. Scanning electron microscope micrographs reveal the creation of free volume on the surface of electrolyte films. Analysis of electrical properties shows a slight increase in ionic conductivity with dye incorporation. Photoluminescence intensity increases with dye due to reduced free volume size. Doped samples emit 97% purity yellow enhancing electrical and optical properties.

Enhancing wear resistance in Al-7075 composites through conventional mixing and casting techniques

Aluminium 7075 alloy composite are highly sought after materials because of their superior strength, light weight and exhibiting enhanced tribological characteristics. An electric resistance furnace and the metal die process were used to develop this aluminium (Al 7075) alloy hybrid composites, with reinforcing provided by E-glass short fibres and aluminium oxide (Al2O3) particulates. The Al 7075 alloy composites have been cast by employing stirring technique at various weight percentages of E-glass short fibres (2 %, 4 %, 6 %, and 8 %) and Al2O3 particles (3 %, 6 %, 9 %, and 12 %). Microscopic examination demonstrates that Al2O3 particle distribution within Aluminium matrix has been uniform. Hardness of the in-situ Al–Al2O3-E-glass-based composites rose by 10.58 %, 22.35 %, 50.58 %, and 41.17 % in comparison to its base alloy. Tensile strength of the 2 to 8 wt% E-glass with 3–12 wt% Al2O3 stir-cast composites increased by 9.08 %, 15.91 %, 19.09 %, and 7.27 % when compared with the aluminium matrix, whereas ductility reduced by 8.9 %, 12.5 %, 18.75 %, and 25 %. An experiment on wear rate was carried out using a pin-on-disk benchtop test equipment. The examination was performed at varying weights and sliding speeds, and the resulted demonstrated that composite materials exhibit higher wear resistance than Al matrix. Furthermore, the presence of Al2O3 and E-glass resulted in lower wear loss across all applied loads and sliding velocities. Lower wear rates in these composites were attributed to hardness and the interfacial bonding between the Al alloy and the in-situ reinforcement.

Investigation on the effect of SiC and TiB2 ceramic particles on mechanical and tribological properties of Al7075 hybrid metal matrix composites prepared through conventional stir casting technique

Materials with lightweight construction, high strength and wear resistance are preferred in the automotive sector and aluminium is found to be a natural choice for the manufacturers. In this work, Al7075 hybrid metal matrix composites enhanced with SiC (6% weight fraction) and TiB2 (2%–6% weight fraction) particles were fabricated by stir casting technique. The characterisation of internal structure of the developed composites was done by subjecting them to scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). It was found that the reinforced particles were uniformly distributed in the aluminium matrix alloy, and only a few clusters were found in the matrix alloyed with 6% TiB2. The tensile strength, hardness and flexural strength of the hybrid composites increased with increase in the weight percentage of reinforcements and attained a maximum of 233.34 MPa, 220 Hv and 458 MPa, respectively, when reinforced with a maximum of 6% SiC and 6% TiB2. The elongation percentage and the impact strength of the hybrid composites start to decrease with an increase in reinforcement percentage and attained a minimum of 6.74% and 1.2 J, respectively, when reinforced with a maximum of 6% SiC and 6% TiB2. By adjusting the input parameters such as load, sliding speed, and sliding distance, the sliding wear behaviour of the hybrid metal matrix composites was explored. It was discovered that the wear rates and coefficient of friction of the hybrid composites decreased with an increase in reinforcement percent. As a result of exhibiting superior mechanical and tribological capabilities, the results show that Al7075 with 6 wt.% SiC and 6 wt.% TiB2 hybrid composite performs the best over all other hybrid composites.

Enhancing Tribo-Mechanical and Corrosion Properties of ADC 12 Alloy Composites through Marble Dust Reinforcement by Squeeze Casting Technique.

This research intends to enhance the tribo-mechanical and corrosion properties of ADC 12 alloys by incorporating marble dust (MD) as a reinforcing element. Composites with varied MD concentrations (0-10 wt%) were fabricated using a squeeze casting process, addressing the limitations of conventional casting techniques. The microstructural analysis confirmed homogeneous MD dispersion within the ADC 12 matrix, facilitating an effective load transfer and solid interfacial bonding. As MD content increased, the experimental density decreased, while porosity increased from 1.22% to 3.97%. Remarkably, adding 4 wt% MD yielded a 20.41%, 17.63%, and 15.75% enhancement in hardness, tensile, and compression strength compared to the as-cast ADC 12. Incorporating MD particles facilitated Orowan strengthening and Hall-Petch strengthening mechanisms, contributing to the observed improvements. The wear rate was reduced by 18.33% with MD content, showing a 17.57% corrosion reduction at 72 h. These outcomes establish the synergistic benefits of ADC 12 squeeze casting with MD reinforcement, delivering superior tribo-mechanical and corrosion properties.

Research on the Quality of Partially Removable Skeletal Prostheses Made Using Classical Versus Modern Sintering Techniques.

Conventional partially removable skeletal dentures are one of the most common therapeutic solutions offered to edentulous patients worldwide. The present study aims to compare the skeleton of removable dentures realized via classical techniques to that realized via modern techniques, represented by the laser sintering technique, with the comparative aspects being realized through the evaluation of atomic force microscopy (AFM). A total of 20 metal frameworks made of Co-Cr were sectioned, representing the infrastructure of partially removable skeletal dentures, developed using the classical technique versus the laser sintering technique. The infrastructures of partially removable skeletal dentures were designed for both the maxilla and the mandible, with the design of each type of denture being identical, and were developed using both techniques. The roughness values are different depending on the technological method used; for the conventional casting technique, we have higher roughness for the component elements of the partially removable skeletal denture that have more stretch, e.g., the major connector, and for the 3D laser sintering technique, lower roughness is obtained for the component elements that have a lower stretch, e.g., the clasp arms, the minor connector, or the junction between the saddles and the major connector. The clinical implications of the presence of roughness at the level of the active arms or at the level of the connector saddle junction are represented by the risk of fracture, which confers real discomfort to the patient.

Carrier transport and Negative differential resistance of electrically bipolar devices based on poly(3,4-ethylene-dioxythiophene): Poly (styrene sulfonate) film

A poly (3,4-ethylene-dioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) film sandwiched between copper electrodes was used to create an electrically bipolar device using a conventional casting technique. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray spectroscopy (EDX) were used to investigate the structure, morphological behaviour, and homogeneous distribution of PEDOT conducting grains in the insulator matrix PSS. The device exhibits normal hysteretic electrical behaviour and a negative differential resistance (NDR) effect in the swept current-voltage (I–V) curves. By varying the PEDOT:PSS films' positive charge voltage and charging rate, the NDR effect may be tuned. A maximum current ratio of 103 can exist between the High Conducting State (HCS) and the Low-Conducting State (LCS). Complex impedance measurements of the Cu/PEDOT:PSS/Cu device were carried out at applied ac-voltage amplitude, Vac, range from 0.1 V to 2 V and over the frequency range from 100 Hz to 10 MHz at room temperature. Different models based on ac and dc experimental data are used to characterize and confirmed the carrier transport processes in the HC, LC-States and NDR.

Recycling of brass chips by sustainable friction stir extrusion

Due to the high economic and environmental benefits, researchers have considered recycling metal chips, especially for the more valuable alloys of copper, brass, aluminium, etc. Several methods have been used including casting and solid-state techniques for recycling the metal chips, wasted annually in large quantities by machining processes. This work examines the sustainability of the Friction Stir Extrusion (FSE) technique, as one of the most recently developed methods for recycling metal chips, comparing it to six different casting methods. Four sustainability indicators of economic, environmental, social, and mechanical performance are calculated and compared for the FSE and casting methods, using a multi-dimensional sustainability methodology. In terms of environmental, social, and mechanical indicators, the FSE method gained significantly the highest levels and in overall sustainability, it achieved the best score of 0.78, while the worst casting technique for recycling was 0.514. However, economically, the FSE has not yet gained a foothold in the industry and needs more attention from manufacturers, environmentally friendly craftsmen, and recycling firms side. Despite the higher investment required for the FSE process (compared to conventional casting techniques) and its lower economic feasibility, the FSE is expected to become more economically viable in the future by further research and development in its tools.

Temperature-Properties Relationships of Martensitic Stainless Steel for Improved Utilization in Surgical Tools

Sintering temperature and environment plays a very important role in strengthening powder particles of compacting surgical parts by cold powder metallurgy technique. Powder metallurgy is a process of producing components/tools by compacting finely metallic or nonmetallic powders. Generally, in the last decade, these tools were produced by conventional casting techniques but now first time in Pakistan this technique is introduced to develop surgical tools/parts. In this study, the effect of sintering behavior by varying temperatures and environments was studied. The AISI 420 Stainless steel compacted surgical parts (Scalpel and scissor) were sintered at 1000 °C to 1300 °C for 30 minutes in a vacuum and an inert environment in the presence of Argon. The compact density, microstructure and mechanical properties were studied. Microstructural characteristics like porosity, and crystalline size were studied by optical microscope. The hardness values and density of the final parts were also measured through the Rockwell hardness machine and by the Archimedes principle. Decreasing the porosity in the final parts will increase the mechanical properties of sintered parts. Adopting the present process for the development of surgical tools after further refining, the process will prove beneficial in the cost-effectiveness, time and energy saving of the present product.

Production and characterization of Al–Cu binary alloy produced by using novel continuous casting process

Abstract Aluminium (Al) and its constituent alloys has been consistently favoured as a promising material for industrial applications. In conventional casting technique of Al alloys, alloying elements are amalgamated in molten pool of Al melt followed by manual skimming. In contrast, batch type manufacturing includes intrinsic mixing and casting discontinuity, which negatively impacts the flexibility and cost-effectiveness of the process, resulting in a decline in the overall efficacy of the process. In the present study, a novel continuous casting processing route has been used to make Al–Cu binary alloys of different compositions. The newly designed technique makes use of a novel mechanical force convection technology, as well as bottom feeding of the molten metal and alloying element throughout the manufacturing process. The bottom feeding along with rotational swirl ensures better amalgamation of alloying element. Feed rates of Al melt and Al–Cu master alloy were mathematically modelled to obtain the desired alloy composition. The microstructural characterization of the developed alloys exhibit Al–Cu intermetallic phase invariably distributed throughout the sample, which concludes a better performing processing route to prepare Al–Cu binary alloys.

INFLUENCES OF P AND Sr ON MICROSTRUCTURE AND ITS EFFECTS ON MACHINABILITY AND MECHANICAL PROPERTIES OF HYPEREUTECTIC Al-20%Si

Hypereutectic Al-Si alloys are widely utilized in the automotive industry due to their high strength-to-weight ratio, minimal thermal expansion, and superior castability. The downside of hypereutectic Al-Si alloys is the formation of coarse primary silicon particles. The primary Si phases were controlled by the growth-hindering agents, phosphorus (refiner), and strontium (modifier) by using a conventional stir casting technique at room temperature. The microstructural changes were observed through an optical microscope and SEM analysis. The additions of 0.08% P have ensured the formation of the uniformly distributed fine-grained particles in the alloy. The primary silicon particle size was reduced from 220[Formula: see text][Formula: see text]m to 150[Formula: see text][Formula: see text]m as compared to the untreated alloy. The tensile and yield properties of the treated alloy were increased by 12.7% when compared to the untreated alloy with a hardness of 131 BHN. The treated alloy imparted better impact toughness, ensuring a ductile mode of failure through the fractography studies. The influence of the microstructure on the machinability of the alloy was investigated in a dry environment with uncoated and coated inserts (code: CCGT 09T304 FL K10) by varying the process parameters, i.e. speed, feed rate, and depth of cut (DoC). Modification of the primary and eutectic Si phases of an Al-20Si hypereutectic alloy increases machinability with coated inserts as well as its mechanical properties.

Comparative Evaluation of Retention and Vertical Marginal Accuracy of Co-Cr Copings Fabricated Using Three Different Techniques: An In Vitro Study.

This study was conducted to comparatively assess the retention and vertical marginal fit of cobalt-chromium copings fabricated by the conventional casting technique, 3D-printed resin pattern, and with direct metal laser sintering (DMLS) technique. Out of the total 60 test samples, 20 copings were obtained from inlay-casting wax and 20 from casting of 3D-printed resin patterns. In total, 20 copings were obtained from the laser sintering technique. All 60 test samples were then cemented serially on the prepared maxillary-extracted premolars and were evaluated for vertical marginal gap in 8 pre-established reference areas. Retention was evaluated using a universal testing machine. Results obtained for both marginal gap and retention were statistically analyzed, and the values fall within the clinically acceptable range. The DMLS technique proved precedence over the other two techniques used, as it exhibited maximum retention and marginal accuracy, which is an area of prime concern. The results from this study encourage further research with different pattern-forming materials and techniques and the need to identify the factors that facilitate better marginal fit and retention of cast restorations. This study has myriad of applications in clinical dentistry mainly in decision-making for casting procedure to provide better retention and marginal accuracy for fabrication of Co-Cr crowns. It also aims to aid the clinician to minimize errors by using different techniques for fabrication of wax pattern as well as the coping, keeping abreast with the recent technology to evaluate the accuracy of 3D-printed resin pattern over conventional wax pattern.