Semi-solid Casting Research Articles

Editorial of the 2nd issue of Engineering Manufacturing Letters

This is the second issue of the Engineering Manufacturing Letters (EML). The journal is published by the University of Porto and invites submissions from a diverse array of industries, including transportation (automotive, rail, aeronautical, and marine), packaging, electronics, sports, and more. Additionally, academic institutions and research institutions are encouraged to contribute their research findings in this field. Accepted topics encompass additive manufacturing, vacuum-assisted high-pressure die casting, semi-solid metal casting, compressive and tensile forming processes, micro and nano machining, nanocomposite manufacturing, adhesive bonding, laser cutting and joining, and related areas. Specific subtopics include process modelling and optimization, design for manufacturing strategies, development of novel manufacturing technologies and equipment, comparative case studies, cost-benefit analyses, ecological considerations, and destructive and non-destructive testing of manufactured components. Technological advances in manufacturing often outpace traditional scientific publication methods. To bridge this gap, our journal focuses on concise reports and letters highlighting innovative manufacturing processes. The journal is open access, but no fees will be charged to the authors until the journal is indexed in the major databases. This journal is associated to the international conference on Engineering Manufacture that takes place every even years in May at the Faculty of Engineering of the University of Porto (www.fe.up.pt/em2024). The editorial board of this journal includes experienced researchers from all disciplines of engineering manufacture. The papers presented in this first issue are varied. They include papers on health monitoring (Vilela et al.), mechanical characterization (Oliveira et al.) and short papers, two papers on metal forming (Peixoto et al., and Winiarski et al.) and additive manufacturing (Nogueira et al., and Sardinha et al.) which is one very dynamic field at the moment. We extend our sincere thanks to the authors for their gently participation in this second issue. The submitted papers offer valuable insights into the recent advancements in engineering technological processes. These contributions serve as a good foundation for what promises to be a dynamic forum of the last developments in engineering manufacturing.

Interfacial bonding mechanism of graphene nanoplatelets reinforced AZ91D magnesium alloy prepared by semi-solid injection molding

The incompatibility between the strength and thermal conductivity of magnesium alloys limits their application in heat dissipation components. Magnesium matrix composites were obtained by adding reinforcements into the AZ91D alloy to achieve synergistic enhancement of mechanical and thermal conductivity to promote the application of magnesium alloy. Graphene nanoplatelets (GNPs) reinforced magnesium matrix composites were successfully prepared by semi-solid injection molding. The high viscosity of the semi-solid metal slurry contributes to the homogeneous dispersion of GNPs in the magnesium matrix. A GNPs/MgO/Mg heterostructure with high interfacial bonding strength was found at the interface of GNPs and α-Mg matrix. The semi-solid casting method improves the mechanical properties of the composites by grain refinement and simultaneously reduces the thermal conductivity. The addition of GNPs can balance the mechanical and thermal conductivity enhancement, and the most balanced properties of the composites are obtained when the content of GNPs is 0.3 wt%, with a tensile strength of 243.1 MPa, Vickers hardness of 93.7 HV, and thermal conductivity of 74.8 W/(m·K). Therefore, the semi-solid forming method is considered a promising processing method, and GNPs is considered an ideal reinforcement material to improve the performance of the magnesium matrix.

Microstructural regulation, work hardening and fracture behavior of Tip reinforced Mg‐xGd‐2Y‐3Zn (x=5, 7, 9 wt%) composites

In this work, Tip/Mg‐xGd‐2Y‐3Zn (x=5, 7, 9 wt%, Tip/GWZx23) composites were fabricated using semi-solid stirring casting and hot extrusion. The Tip/Mg laminar-like configuration was regulated by Gd content. The effect of Tip/Mg laminar-like configuration on the microstructure, mechanical properties, work hardening and fracture behavior of Tip/GWZx23 composites was thoroughly studied. The results revealed that the Tip elongated along the extrusion direction (ED) after extrusion and formed Tip/Mg laminar-like configuration with the Mg matrix. With the increase of Gd content, the hardness of the matrix increased, which was beneficial to the elongation of Tip. The elongation of Tip reduced its hardness value, released the stress and promoted the DRXed grain refinement. The refined grain enhanced the ability of grain boundaries to absorb dislocations and improved the recovery effect. Furthermore, the formation of Tip/Mg laminar-like configuration induced back stress strengthening at the Tip/Mg interface, enhancing the work hardening rate of the Tip/GWZx23 composites. The Tip/Mg laminar-like configuration changed the strain distribution and the strain was transferred from the Tip sharp corner to the elongated Tip, which was effectively alleviates stress concentration at the Tip/Mg interface and inhibited crack propagation.

Tribological and microstructural characteristics of Al2O3–LM6 semi-solid cast composite synthesized by dual mixed slurry process

The purpose of this work is to analyze the impact of reinforced Al2O3–LM6 aluminum composite made with dual mixed slurry for semi-solid casting with stirring, which is documented according to microstructure and wear properties. Under dry sliding pin-on-disk conditions, the composition and surface morphology of worn surfaces were carefully examined for the 10 N applied force, 1.2 m/s sliding speed, and sliding distances up to 750 m. Experimental findings indicate that Al2O3 reinforcement with semi-solid dual slurry effects give outstanding resistance against the adhesive wear. Microstructure, EDS, and XRD results from worn surface evaluation all show evidence of protective layers, which helps explain the reason for the rate of wear decreased due to processing. In this experiment, LM6 serves as the matrix material and Al2O3 as reinforcement. Al2O3–LM6 semi-solid cast composite was created via a dual mixed slurry technique with temperature control close to the solidus line for varying compositions. This work reports a substantial relationship between metallurgical and mechanical parameters. Mechanical properties and wear characteristics have been investigated.

Effect of Self-Pouring Temperature on the Microstructural Characteristics of Al2O3-LM6 Semi-solid Cast Composite

Effect of Self-Pouring Temperature on the Microstructural Characteristics of Al2O3-LM6 Semi-solid Cast Composite

Semisolid stir processing of AZ91/TiO2 nanocomposite analysis with SiC exposure: behaviour measures

ABSTRACT This research affair to synthesize the magnesium alloy (AZ91) hybrid nanocomposites with 0.5wt% titanium dioxide (TiO2) and 2.5, 5, and 7.5wt% of silicon carbide (SiC) nanoparticles through a semisolid stir cast route under argon (inert) nature and its particle distribution enhanced with uniform stir speed of 400rpm as well as the casting defects reduced by using nature of inert. The excellence of semisolid stir processing with SiC exposure on AZ91/TiO2 composite is analyzed with physical, surface morphological and mechanical exploits. Compared to aluminium-based composites, this composite weight is less, with an acceptable level of voids (less than 1.5%). An effort of processing, the microstructure proved their SiC and TiO2 appearance as uniform. The AZ91/0.5wt%TiO2/7.5wt% SiC exploited maximum hardness of (84±0.8HV), impact toughness of (16.3±0.3J/mm2), and excellent strength (251±5MPa) with reduced elongation percentages of (4.5%). This optimum property sample will be planned for automotive roof frame applications.

Improvement of strength and ductility of TC4p/AZ91D magnesium matrix composites by modifying the extrusion ratio

In this study, AZ91D (Mg-9Al-Zn) alloys reinforced with 2 vol% TC4 (Ti–6Al–4 V) particles fabricated by semi-solid stir casting were extruded at different ratios, resulting in observed grain refinement effects. The research findings demonstrate that both TC4 and β-Mg17Al12 phases contribute to promoting dynamic recrystallization (DRX) nucleation. With increasing extrusion ratio, the β-phase (Mg17Al12) gradually fractures into smaller particles, leading to progressive grain refinement. Furthermore, the transition from 〈01–10〉 fiber texture to non-basal texture in the α-Mg matrix after hot extrusion is attributed to improved DRX behavior and activation of non-basal slip. As the extrusion ratio increases, the tensile strength and elongation (EL) of TC4p/AZ91D composite improve significantly, reaching optimum comprehensive mechanical properties at an extrusion of 40:1 with a yield strength (YS) of 257 MPa, an ultimate tensile strength (UTS) of 357 MPa, and an EL of 9.7%. This remarkable strengthening effect is primarily attributed to β-phase reinforcement, grain refinement strengthening, and strain hardening.

A Concise Overview on Orodispersible Film along with their Formulation and Characterization Technique’s

Orally fast-dissolving medicine delivery techniques are increasingly common at present. Due to the desire for these delivery systems, oro-dispersible film (ODF) was recently introduced for the delivery of medicines via the oral route. Most of drugs are delivering through oral route in the form of tablets, capsules and liquids, because they are simple to make and have a greater level of patient compliance. But these conventional dosage forms have many problems including big size of dosage form, and fear of chocking. Oral rapid disintegrating/oro-dispersible drug delivery systems were created to tackle such issues. Fast dissolving films were invented for the patients who have swallowing issues with conventional/traditional oral solid dosage forms. They also have a quick onset of effect, taking only a few seconds, because the drug is absorbed directly from the injection site to the systemic circulation, avoiding first-pass metabolism. In the preparation of films, polymers, surfactants, flavoring agents, coloring agents, sweetening agents, saliva stimulating agents, drug, and plasticizer are used. The drug incorporated in ODF should have pleasing taste, low molecular weight, high stability, and high aqueous solubility. Solvent and semisolid casting, hot melt extrusion, and rolling techniques are routinely used to prepare ODFs. Thickness, loss on drying, tensile strength, and elongation percentage are commonly assessed for evaluating ODFs, as well as their resistance to tearing, weight variation, folding endurance, pH, swelling property, transparency, disintegration, dissolution rate, and stability. The purpose of this review article is to provide a quick overview of ODF delivery systems.

Smart-Cast: An AI-Based System for Semisolid Casting Process Control

To satisfy the rising demand for higher product quality and giga-casting requirements, the casting process is undergoing significant changes. However, current control methods rely significantly on human expertise and experience, making process availability and stability difficult to ensure. The semisolid casting process is more complicated than conventional liquid casting due to the additional casting parameters incorporated during the slurry preparation, which can have an effect on the quality of the final product. Therefore, an efficient tool is required to simplify the complete process of semisolid casting. The introduction of an AI system to aid in the supervision of the casting manufacturing procedure is one potential solution. This paper introduces a new casting system named ”Smart-Cast” developed for this specific purpose. The paper describes the functions of the system and its current development process. Using an AI system as an assistant can help to achieve the goal of enhancing the efficacy of casting process control, and it can also help foundries step into the Industry 4.0 era.

Fast Dissolving Oral Films: Formulation, Evaluation and Future aspects

Fast dissolving oral film (FDOF) are drug delivery systems of the new days having one of the highest patient compliance, safety and are economical than most other dosage forms. Hydrophilic polymers when used as a vehicle come in contact with water get hydrated and thus allow drug release. Hydrophilic polymers also show an adherence property post hydration. Thus the hydrating and adhering properties of hydrophilic polymers makes it most suitable for producing fast dissolving oral film. Fast dissolving oral films are made to be administered into the buccal cavity of humans as the buccal cavity if having saliva and saliva help to hydrate the films leading to drug release. The buccal cavity in humans has a very high amount of blood supply system thus aids in faster drug entrance into the blood circulation. The fast dissolving oral films are capable of initiating drug release within seconds, without chewing and drinking. The instant bioavailability achieved bypassing the fast pass metabolism also adds as a salient feature. Various compositions of different polymers lead to differences in drug release rate of the films. Polymers such as Hydroxy Propyl Methyl Cellulose; Poly Vinyl Alcohol; Ethyl Cellulose; Sodium Carboxymethyl Cellulose are some common hydrophilic polymers that are used to produce fast dissolving oral films. Solvent casting; semi solid casting; hot melt extrusion; solid dispersion extrusion are some common methods of production of fast dissolving oral films. Immediate onset of action in a shorter period with improved bioavailability marked fast dissolving oral film, a dosage form of choice.

The influence of Tip aspect ratio on the microstructure, mechanical properties, and work hardening behavior of the Tip/Mg-Gd-Y-Zn composites

In this work, the spherical Tip was introduced into Mg-7Gd-2Y–3Zn (GWZ723) alloy by semi-solid stir casting process, then the Tip/GWZ723 composites were prepared and subjected to extrusion at 380–450 °C. After that, the aspect ratio of the Tip was adjusted according to the extrusion temperature. The effects of the Tip aspect ratio on microstructure, mechanical properties, and work-hardening behavior of Tip/GWZ723 composites were investigated. The results revealed that after hot extrusion, the Tip elongated along the extrusion direction (ED), and its aspect ratio increased as the decrease of extrusion temperature. When the extrusion temperature decreased to 380 °C, the aspect ratio of the Tip reached to 12:1. With the increasing Tip aspect ratio, the hardness of the Tip decreased while the Mg matrix increased. Moreover, both the recrystallized grains and LPSO phase were also refined simultaneously. The yield strength (YS), ultimate tensile strength (UTS), work hardening rate and dynamic recovery rate of the Tip/GWZ723 composites increased with the increasing of Tip aspect ratio. During the tensile process, strain concentration tended to occur at the sharp corner of the elongated Tip, nevertheless, the strain distribution in the matrix became more uniform accompanied with the increasing Tip aspect ratio, which was conducive to suppress crack initiation and delay fracture. It was the laminar-like configuration formed by the elongated Tip and the Mg matrix along the ED contributed to the excellent comprehensive mechanical properties of the Tip/GWZ723 composites. When the Tip aspect ratio was 12:1, the YS and UTS reached as high as 454.3 MPa and 492.2 MPa, respectively.

To improve robustness of mechanical properties of semi-solid cast A356 alloy using taguchi design method

To improve robustness of mechanical properties of semi-solid cast A356 alloy using taguchi design method

Effect of solid solution treatment on microstructure and mechanical properties of Al–Si–Cu–Mg alloy prepared by semi-solid squeeze casting

Effect of solid solution treatment on microstructure and mechanical properties of Al–Si–Cu–Mg alloy prepared by semi-solid squeeze casting

Investigation of the Mechanical Properties and Microstructure of Graphene-Aluminium Alloy Composite Fabricated by Stir Casting Process

Mechanical properties of graphene nanoplatelets (GNPs) reinforced aluminum matrix composite fabricated by the semi-solid stir casting method were investigated. Aluminum alloy A356 is selected based on being widely used in automotive and aircraft industries. Recently, graphene has attracted wide attention from a scientific committee due to its outstanding properties. GNPs are an ideal reinforcement for nanocomposites' productions due to their excellent mechanical properties for strength enhancement. In this study, the effect of different weight fraction of GNPs content (0,0.3,0.5,1.0,and 1.5 wt.%) reinforced with A356 aluminum alloy was analysed. A 45-degree carbide impeller performed the stirring process of 500 rpm for 5 minutes. The samples were then characterised by microscopic examination, Vickers hardness, and tensile test Morphology of the fracture surface of the composite were observed using scanning electron microscopy..The microstructure revealed a homogenous distribution of nanoparticles in the matrix alloy. The composite exhibits improved mechanical properties, maximum tensile strength and hardness of 236MPa and 83 HV are obtained respectively. The composite has shown significant enhancement in the tensile and hardness which is 20% times higher than unreinforced A356 alloy. The hardness increased as the weight fractions of GNP in the A356 matrix has increased. However, when the content of GNPs used above 1.0 wt%, its tensile strength is reduced. Meanwhile, the fracture sample is ductile with a fine dimple structure. These findings may contribute to the process field of semi-solid stir casting, particularly on the GNPs addition to aluminium alloy as their primary material.

Impact of Processing Conditions on the Fluidity and Consistency of GISS-Processed Semi-Solid Aluminum Alloys

GISS (Gas Induced Superheated Slurry) is one of the more popular processes for the production of commercial semi-solid castings. For the successful production of high-quality castings, it is necessary to understand the impact of processing parameters on the flow behavior of the semi-solid metal. This paper describes the results of laboratory studies to examine the effects of processing conditions on the development of semi-solid feed material during GISS processing for two aluminum casting alloys, ADC12 and A356. Two series of tests were performed. The first involved a simple pouring test along an inclined section of a v-channel, to determine if differences in flow behavior could be identified. The second series of trials examined the effect of processing temperature and time on the consistency and flow behavior of the aluminum alloys. Ladles of molten aluminum alloy were treated using the GISS process at different temperatures for between zero and 10 seconds. After the treatment, the alloy was allowed to further cool in the ladle into the semi-solid temperature range, at which time the flow behavior of was compared. Consistency more suited to semi-solid casting was obtained when the GISS treatment temperature was lower and treatment time longer.

Venting Systems in Semi-Solid Processing of Aluminium

In the automotive industry, casting products produced by high pressure die casting are essential. Due to the higher mechanical demands on these castings, the technological requirements of the process are also increasing. Therefore, the control of the microstructure and the development of defects play a major role. High pressure die casting parts made of aluminium usually contain gas porosity due to gas compression during the filling process of the cavity and the intensification during solidification. The use of semi-solid casting thus opens new doors to fulfil promising future demands. In this study, the venting system was adapted to the RheometalTM process of aluminium and designed in the form of gaps, thus ensuring better venting. Subsequently, the results obtained were compared with casting process simulations to highlight possible differences.

Effect of Ingate Length on Microstructure and Properties of Semi-Solid Squeeze Casting CuSn10P1 Alloy

It is easy to occur solid-liquid separation during semi-solid rheological forming, which leads to poor uniformity of microstructure and properties and limits its application in high strength and toughness parts. In this paper, a semi-solid CuSn10P1 alloy slurry was prepared by an enclosed cooling slope channel (for short ECSC). The effect of ingate length on microstructure and properties by semi-solid squeeze casting was studied. The results showed that the proper increase of the length of the ingate is beneficial to improve the uniformity of the microstructure and properties of the semi-solid squeeze casting. The microstructure uniformity and properties are the best when the ingate length is 20mm. The ultimate tensile strength and elongation of semi-solid squeeze casting CuSn10P1 alloy with 20 mm ingate length reached 419.2 MPa and 13.4%.

Semi-Solid Casting of AlN Reinforced Mg-Matrix Composites and their Thermophysical Properties

AlN has high thermal conductivity (TC) and low coefficient of thermal expansion (CTE), which is an ideal reinforcement phase for strengthening the thermophysical properties of magnesium alloys to be used as packaging substrate material. However, the poor wettability between AlN and magnesium melt makes the preparation of AlN/Mg composites with high AlN content very difficult. In this work, the AlN/Mg-5Zn-4.9Cu composites were prepared by semi-solid stir casting method to address this problem, and the effect of AlN particle content on the thermophysical properties of the composites was investigated. The results show that AlN can reduce the CTE of magnesium alloy significantly and weaken the TC of magnesium alloys slightly. When 20 wt.% of AlN was added, the TC of the composites was 125.1 W/(m·K) and the CTE was only 19.83×10-6 K-1, which was 26.7% lower than that of the matrix alloy.

Rheological Behaviour of Secondary AlSi7Mg Alloy for Semi-Solid Processing

Semisolid castings are usually produced using primary Al alloys to ensure significant mechanical performances. However, the need to increase the use of secondary alloys is becoming more and more urgent to reduce the carbon footprint of the manufacturing process. In fact, it is well known that the production of primary alloys is far more demanding in terms of energy and emissions than the recycling route. To extend the use of secondary alloys to semisolid processing, it is necessary to thoroughly understand their properties and how they can influence a material with peculiar properties as the semisolid one. Besides microstructural and mechanical features, the rheological behaviour also plays a major role when dealing with processing metals in the semisolid state. Therefore, in the present study, a rheological characterization of secondary AlSi7Mg commercial alloy was carried out and compared to that of the conventional primary alloy. In details, a different content of Fe, Cu and Mn was considered, as these impurities easily form primary intermetallic particles, which can remain dispersed in the liquid matrix of the semisolid metal. The aim of this work is to understand if this can affect the rheological properties of the considered semisolid alloy. Flow curves and yield stresses were obtained from the experimental results to compare the behaviour of the different alloys.

On the Possibility of Replacing Scheil-Gulliver Modeling with Machine Learning and Neural Network Models

Resource-efficient manufacturing is a foundation for sustainable and circular manufacturing. Semi-solid processing typically reduces material loss and improves productivity but generally requires a better understanding and control of the solidification of the cast material. Thermal analysis is commonly used in high-pressure die casting (HPDC) processes to determine casting process parameters, such as liquidus and solidus temperatures. However, this method is inadequate for semi-solid casting processes because the eutectic temperature is also a crucial parameter for successful semi-solid casting. This study explores the feasibility of using machine learning and artificial neural networks to predict fundamental values in Al-Si alloy casting. The Thermo-Calc 2022 software Scheil-Gulliver calculation function was used to generate the training and the test datasets, which included features such as melting temperature, alpha aluminium solidification temperature, eutectic temperature, and the solid fraction amounts at eutectic temperature. The results show that both models have a symmetric mean absolute percentage error (SMAPE) of less than 2 % with temperature prediction, with the machine learning model achieving a better accuracy of less than 1 %. A case study comparing practical measurements with prediction results is also discussed, demonstrating the potential of AI methods for predicting semi-solid casting processes.