Molten Aluminum Alloy Research Articles

Reaction Behavior at the Contact Interfaces between High-Manganese Cast Steel or High-Manganese Spheroidal Graphite Cast Iron and Molten Aluminum Alloys

Reaction Behavior at the Contact Interfaces between High-Manganese Cast Steel or High-Manganese Spheroidal Graphite Cast Iron and Molten Aluminum Alloys

Anisotropic corrosion behavior of laser-based direct energy deposited H13 steel in molten ADC12 aluminum alloy

The immersion corrosion experiment of laser-based direct energy deposited H13 steel in ADC12 aluminum alloy melt was conducted to evaluate the demands for corrosion resistance after mold repair. The effect of the anisotropic microstructure of the deposited H13 steel on corrosion behavior was elucidated by characterizing the microstructure before and after corrosion. The results show that the microstructural heterogeneity affects the initiation, development and stabilization process of corrosion. Corrosion tends to initiate near the heat-affected zone due to the heterogeneous distribution of grain size, carbides, and dislocation density. Planes with weak microstructural heterogeneity are less likely to develop cracks in the intermetallic compounds (IMCs) layer during the corrosion development stage, thus exhibiting a slower corrosion rate. The IMCs layer of plane with weak microstructural heterogeneity stabilizes more quickly during the corrosion stabilization stage. The plane perpendicular to the build direction exhibits the highest corrosion resistance due to fewer corrosion initiation locations and the weakest microstructural heterogeneity. Furthermore, the composite structure of carbide core + Si phase shell, generated during corrosion, contributes to improving localized corrosion resistance. This study provides insights into understanding the influence of the heterogeneous microstructure from additive manufacturing on the reaction-diffusion process and offers guidance on direction selection when preparing components for applications in contact with aluminum melts using additive manufacturing techniques.

Investigations on Mechanical Properties of Nano Particulates (Al<sub>2</sub>O<sub>3</sub>/B<sub>4</sub>C) Reinforced in Aluminium 7075 Matrix Composite

Metal Matrix Nano Composites (MMNCs) with the addition of nano-particulate reinforcements can be of significance for automobile, aerospace, and numerous applications due to their low density and good mechanical properties, better corrosion and wear resistance, low coefficient of thermal expansion as compared to conventional materials. Designing the metal matrix composite material aims to combine the desirable attributes of metals and ceramics. The present work is focused on studying the mechanical properties of aluminium alloy (7075) with Al2O3 and B4C nanocomposite produced using the stir casting technique and ultrasonic cavitation method. Different % age of reinforcement is used. An ultrasonic cavitation technique is used to achieve a uniform dispersion of nano-particulate Al2O3 and B4C in molten aluminium alloy. Tensile, Hardness, and Impact tests were performed on the samples obtained by the fabrication processes. A structural study will be carried out through a Scanning Electron Microscope (SEM) to know the distribution of Al2O3/B4C Nano particulates in Al alloy.

Design and Simulation of a Maintenance-friendly and Cost-effective Molten Aluminum Alloy Casting Mechanism

Design and Simulation of a Maintenance-friendly and Cost-effective Molten Aluminum Alloy Casting Mechanism

Study on the microstructure and mechanical properties of hot rolled nano-ZrB2/AA6016 aluminum matrix composites by friction stir processing

In this paper, in-situ ZrB2/AA6016 particle-reinforced aluminum matrix composites were prepared in molten A6016 aluminum alloy melt by KBF4-Al- K2ZrF6 reaction system. For the first time, this paper presents that after casting, the composites would be subjected to large strain hot rolling (LSHR) with 60 % undercutting and then friction stir processing (FSP) with a stirred probe speed of 1200 r/min and a traveling speed of 60 mm/min. To study the microstructure and mechanical properties of composites strengthened by large strain hot rolling combined with friction stir processing. The results show that the tensile strength of the base material is 140.1 MPa, the elongation is 46.3 %, the product of strength and elongation reaches 6.5 GPa%, and the average hardness is 43.4 HV; The tensile strength of LSHR+FSP nugget zone is 163.4 MPa, the elongation is 78.9 %, the product of strength and elongation reaches 12.9 GPa %, which is about 98.6 % higher than the base material, and the average hardness is 59.8 HV, which is about 37 % higher than the base material. SEM, EBSD, and TEM analyses showed that the average grain size is refined from 189.7 μm to 3.8 μm after LSHR+FSP. The ZrB2 particles are sufficiently fragmented, with a particle size of about 20 nm, and uniformly dispersed in the matrix. This study provides the theoretical and experimental basis for applying nanoscale ZrB2 particles reinforcing ultrafine crystalline aluminum matrix composites prepared by LSHR + FSP.

Selected challenges in solidification processing of graphene nanoplatelets (GNPs) reinforced aluminum alloys composites

Solidification processing of aluminum graphene composite is an attractive option for synthesis of metal matrix composites. Graphene reinforced aluminum metal matrix composites (GAMMCs) are of interest due to the low density and ultrahigh physical and mechanical properties of Graphene which can improve the properties of Al-Graphene composites. However, solidification processing of aluminum graphene composites has served challenges, including agglomeration of reinforcement and porosity resulting in decrease in properties above 0.five to three wt% graphene. Also, the graphene surface can react with molten aluminum alloys to form aluminum carbide. Challenges with particle distribution and porosity are frequently caused by the poor wetting of reinforcement by melt, requiring additions of selected wetting agents. The other problems include movement of reinforcement within the melt due to density differences and convection leading to nonuniform distribution of reinforcements. The graphene reinforcements can be pushed by solidifying interfaces under certain conditions during solidification leading to segregation of reinforcements in the interdendritic regions. The paper critically analyzes the above problems related to solidification processing of Aluminum- Graphene composites which has not been done in previous publications aluminum-graphene composites. The objective of this paper is to examine the challenges, and suggest possible solutions including addition of elements like silicon and magnesium to aluminum melt, coating graphene with metals like nickel and copper, controlling rate of advancement and nature of advancing solid liquid interface in a manner that they engulf graphene with dendrites or grains.

Effect of corrosion pit on fatigue damage and failure in powder bed fusion AlSi10Mg

AbstractThis paper is concerned with environmental corrosion during service of load‐bearing aluminum alloys fabricated by additive manufacturing (AM) with a focus on damage evolution characterization and identification of dominated failure mechanisms of pre‐corroded selective laser melted aluminum alloy. An experimental strategy for analysis of the damage and failure process is presented, combining 3D surface measurement, 3D digital image correlation, and scanning electron microscopy, to provide a multi‐source experimental characterization of corrosion morphology, strain field evolution, and fracture morphology. Statistics and machine learning methods were employed to process the measured multi‐source experimental data, showing that local average roughness has a strong influence on macro‐crack initiation position. The analysis focuses on four primary types of fatigue micro‐crack initiation, namely, internal defect, diffuse corrosion, corrosion micro‐pit, and corrosion jut; internal defect and diffuse corrosion are unique features for powder bed fusion (PBF) AlSi10Mg. The micro‐crack initiation mechanisms for all four types are (i) local stress concentrations due to adjacent material micro‐structural defects, (ii) interaction of underlying alloy microstructure and corrosion‐induced stress/strain, and (iii) local stress/strain concentration at corrosion micro‐pit and jut, respectively.

Erosion Resistance of Heat-Treated Aluminum Cast Iron to Aluminum Alloy Melt

Erosion Resistance of Heat-Treated Aluminum Cast Iron to Aluminum Alloy Melt

Introducing Auxetic Behavior to Syntactic Foams

This paper proposes an innovative multi-material approach for introducing auxetic behaviour to syntactic foams (SFs). By carefully designing the size, shape, and orientation of the SFs, auxetic deformation behaviour was induced. Re-entrant hexagon-shaped SF elements were fabricated using expanded perlite (EP) particles and a plaster of Paris slurry first. Then, an auxetic pattern of these SF elements was arranged within a stainless-steel casting box. The empty spaces between the SF elements were filled with molten aluminium alloy (A356) using the counter-gravity infiltration casting technique. The cast auxetic composite had a bulk density of 1.52 g/cm3. The cast composite was then compressed under quasi-static loading to characterise its deformation behaviour and to determine the mechanical properties, especially the Poisson’s ratio. The cast composite deformation was auxetic with a Poisson’s ratio of −1.04. Finite Element (FE) simulations were conducted to understand the deformation mechanism better and provide means for further optimisation of the geometry.

Effect of ultrasound treatment on the performance and segregation of Al–Cu alloy with different Cd contents

By applying ultrasonic treatment to ZL205A aluminum alloy melt containing different Cd contents and then using a tensile test, a scanning electron microscope experiment, and a metallographic experiment, the influence of ultrasonic treatment to ZL205A aluminum alloy melt on the properties of aluminum–copper alloy with different Cd contents in the liquid phase high-temperature region was studied. The effect of ultrasonic treatment on the solidification structure of ZL205A aluminum alloy was investigated. The results showed that there was no significant difference in the form of Cd and the solid solution rate of the aluminum alloy with different Cd contents in ultrasonic-assisted casting. However, the effect of ultrasonic waves on the high-temperature liquid phase of the melt of ZL205A aluminum alloy can effectively reduce the porosity defects in the solidification structure of the casting, refine the solidification structure, and make the structure more uniform. The ultrasonic cavitation effect can promote the formation and uniform distribution of Al–3Ti and improve the nucleation rate, and the effect can continue after heat treatment. This can solve the problem that increasing Cd content in ZL205A greatly reduces the toughness of castings while increasing the strength. The sample with a Cd content of 0.20% and with ultrasonic treatment has the highest strength, the average tensile strength is 475.5 MPa, and the yield strength is 381.75 MPa. However, compared with the conventional casting samples with the same Cd content, the decrease in elongation was significantly reduced.

Development process and future trends of chemical refining agents' influence on grain refinement in aluminum alloys

Aluminum is the world's largest production of non-ferrous metals, with light weight, high specific strength, excellent electrical and thermal conductivity and other characteristics. With the continuous development of aerospace, precision electronic instruments, photovoltaic semiconductors and other emerging strategic industries, the demand for high-performance materials of aluminum alloys has become increasingly strong. This paper reviews the research progress of aluminum alloy melt refinement treatment, summarizes the development history of grain refinement, and evaluates the advantages and disadvantages of various types of refining agents, such as Al–Ti–B, Al–Ti–C, Al–Ti–B/C–Re, etc. The article points out the shortcomings of the current research on the melt refinement treatment of aluminum alloys, and looks forward to the future research direction.

Erosion Behaviors and Mechanisms of Low-Carbon Steel and Alloy Tool Steel in Commonly Used Molten Aluminum Alloys

Erosion Behaviors and Mechanisms of Low-Carbon Steel and Alloy Tool Steel in Commonly Used Molten Aluminum Alloys

Steel Chips Reinforcement in Aluminum-Based Composites: Revolutionizing Manufacturing via Stir Casting Technique

This study investigates the utilization of waste steel chips as reinforcement in aluminum-based composites through the stir casting technique. Steel chip particles were introduced gradually into the molten aluminum alloy while stirring at 400 rpm for 10 minutes to ensure uniform dispersion. Precise temperature control prevented premature solidification, facilitating effective incorporation of steel chips. The resulting composite exhibited a predominantly uniform distribution of reinforcement, indicating successful processing.The addition of 7.5% waste steel chips led to remarkable improvements in mechanical properties. Tensile strength increased by 15.67%, while hardness showed a substantial enhancement of 25.56% compared to the base composite. Moreover, wear resistance exhibited a notable improvement of 19.45%. These enhancements underscore the efficacy of waste steel chips as reinforcement, revolutionizing manufacturing practices in aluminum composites. The findings highlight the potential for sustainable and cost-effective approaches to enhance mechanical performance, contributing to advancements in materials engineering and promoting eco-friendly manufacturing practices.

Recent advances and future trend of aluminum alloy melt purification: A review

Aluminum, the most produced non-ferrous metal in the world, is highly regarded for its light weight, high specific strength, and excellent thermal conductivity. With the continuous development of aerospace, precision electronics, photovoltaic semiconductors and other emerging strategic industries, the demand for high-performance aluminum alloys is also booming. The paper discusses recent advances in aluminum alloy melt purification, focusing on the development of conventional purification treatment and novel purification treatment of aluminum alloy melt. The advantages and disadvantages of adsorption purification, non-adsorption purification and integrated purification are also summarized. Additionally, the article points out the shortcomings of the current research on aluminum alloy melt purification and gives an outlook on the future research direction.

A qualitative and quantitative investigation of nonmetallic inclusions in molten Al–Mg, Al–Cu, and Al–Zn–Mg–Cu alloys

In this work, a qualitative and quantitative investigation on inclusions in molten Al–Mg, Al–Cu, and Al–Zn–Mg–Cu alloys, and the evolution behavior of inclusions in these three alloys during off-line and on-line purification steps were studied via the porous disc filtration technique. It was found that the removal of oxide from 2219 and 5A06 aluminum alloys melt via furnace refining is difficult, both of which can only remove the oxide by about 27 %, whereas the furnace refining can remove oxide from 7A04 aluminum alloy melt effectively, it can reduce the oxide by 55 %. Moreover, we determined that the furnace refining and degassing can reduce the boride content in 5A06 aluminum alloy effectively, but the boride content in 7A04 and 2219 aluminum alloy varied little after these two purification processes. Also, the furnace refining and on-line degassing were found to increase the carbide in 7A04 aluminum alloy, which was not found in the other two alloys. Further, we correlated the relationship between the slopes of the melt mass-time curves of the filtrates and the inclusion content for 2219, 5A06, and 7A04 aluminum alloys, which implies a higher concentration of inclusion possesses a lower slope for the melt mass-time curves of the filtrates. The obtained result could offer some guidelines for the production of high-quality ingot for the studied three alloys.

Effects of laser power and printing speed on the temperature field during selective laser melting of aluminum alloy

Additive manufacturing (AM) has significantly transformed the manufacturing industry and found diverse applications. Selective laser melting (SLM), as a common and valuable rapid prototyping technology in AM, is also a very important technology. In SLM, temperature is a very important parameter, and parameters such as melting time and manufacturing speed are highly correlated with temperature. However, temperature is not easy to measure in real-time, and it is convenient to study the changes in temperature field through numerical simulation. This paper explores the quantitative impact of printing speed and laser power on the temperature field through simulation. The peak temperature decreases with increasing printing speed, but increases with increasing laser power. The high temperature affected area is mainly related to the printing speed and decreases as the printing speed increases. The relevant results can provide guidance and reference for the application of SLM engineering.

Interaction kinetics between molten aluminium alloy Al99.7 and H11 tool steel with and without an AlCrN protective coating

The tool used in die casting or hot forming is subjected to thermal and mechanical stress, resulting in damage and cracking due to thermal fatigue and melt flow. This reduces the profitability and efficiency of production, as the products may not meet the required dimensions and mechanical properties. Understanding the interaction between tool steel and molten aluminium alloy is critical to extending tool life. AlCrN protective coatings on tool surfaces can improve corrosion resistance, thermal fatigue and wear resistance.The present work was carried out to predict the effect of the AlCrN protective coating on the interaction kinetics between H11 tool steel and molten aluminium alloy Al99.7. The AlCrN protective coating on the H11 tool steel sample served its purpose and slowed down the interaction between the aluminium melt from Al99.7 and the H11 tool steel, as the DSC curve of the sample that had the AlCrN protective coating applied flattened out faster, indicating the cessation of dissolution in the material at all investigated temperatures. Measurements of the thicknesses of the interaction layers also confirmed these results, whereas the thickness of the composite layer was almost the same at both experimental temperatures, 670 °C and 700 °C, respectively, without an AlCrN protective coating; the temperature has no effect on this layer and the types of interaction layers did not differ from each other.

Fast reactive interdiffusion between solid brass and liquid aluminium

The formation mechanisms of intermetallic layers and the development of the interface between solid brass and molten Al alloy were experimentally investigated using semi-infinite solid-liquid diffusion couples. Isothermal annealing of commercial CuZn37 – AA7075 diffusion couples was conducted for the selected temperatures of 650 °C, 660 °C, 680 °C and 700 °C, for three annealing times of 10 s, 20 s and 40 s, followed by quenching. Regardless of the temperature, the interface consisted of three intermetallic layers that are reaction products as defined in the Al–Cu–Zn phase diagram. In order to explain the growth behaviour and bring insights into the interface formation mechanisms, the thermodynamics of the Al–Cu–Zn was investigated by CALPHAD (calculation of phase diagrams). Based on these ex-situ results, three distinct phenomena were observed. First, intermetallic layers dissolve simultaneously into the molten Al alloy when the annealing time exceeds 40 s. Second, parts of the intermetallic layer that are in contact with the molten Al, detach from the interface region in the direction of molten Al alloy leading to a decrease in the layer thickness and deviation from planar-like geometry. Third, the formation of the three intermetallic layers is exclusively the result of solid-liquid interactions followed by quenching. Previous studies have shown a scattered interface character between solid brass and molten aluminium which results from interactions in the solid-solid state due to low cooling rates. As a result, the concept of primary intermetallic layers was introduced to describe the interface formation upon the contact of solid brass with molten aluminium alloy.

Sustainable recycling of aerospace-grade ultra-clean 7050 aluminum alloy melts through argon refining without secondary aluminum dross generation

The refining of aluminum scraps commonly employs nitrogen-fluxes to eliminate impurities. However, the aluminum nitride (AlN) generated by the reaction between nitrogen and the aluminum melt, along with residual fluxes, contribute to low cleanliness of the recycled aluminum melt and pose difficulties for the disposal of secondary aluminum dross (SAD). Our innovative research has resulted in the recycling of aerospace-grade clean aluminum alloy melts. The results indicate that the argon bubble floating process adsorbs inclusions and hydrogen, achieving an aerospace-grade ultra-clean melt. The solid-liquid interface between the tube wall and the melt provides a diffusion channel for hydrogen atoms, and the bubbles rising up along the wall lead to a higher hydrogen content in the melt. The argon refining dross is primarily composed of Al and Al2O3, which can be recycled as a raw material for aluminum electrolysis. Argon refining can decrease the hydrogen content and the number of inclusions with particle size ≥40 μm in the recycled aluminum melt to the level of aerospace aluminum alloy melt. Nonetheless, the particle size ≥20 μm remains 1.5–2.5 times that of primary aluminum.

Fabrication and tunable reinforcement of net-shaped aluminum matrix composite parts via 3D printing

Advanced materials, such as metal matrix composites (MMCs), are important for innovation, national security, and addressing climate change. MMCs are used in military, aerospace, and automotive applications because of their exceptional mechanical and thermal properties, however adoption has been slow due to costly and onerous manufacturing processes. A new process using fused filament fabrication 3D printing has been developed to make net shape MMCs without tooling or machining. The process involves printing an alumina preform and then using pressure-less infiltration with a molten aluminum alloy to form the composite. Arbitrary shapes can be formed in this process—a brake lever and a flange are demonstrated—and the properties can be tuned by varying the ceramic infill geometric pattern and ceramic loading. By using 35 vol% continuous fiber reinforcement over 800 MPa strength and 140 GPa modulus are achieved for the aluminum composite, 3.4 × and 2 × the matrix aluminum properties.