AlSi10Mg Alloy Research Articles

Effect of cooling rates and heat treatment time on Si phase of AlSi10Mg alloy manufactured by selective laser melting: Microstructure evolution and strengthening mechanism

As a processing technique to change the organization and properties of materials, heat treatment was widely used to strengthen metallic materials. This study examines the impact of varying cooling rates and heat treatment durations on the mechanical properties and microstructure of AlSi10Mg alloys produced through Selective laser melting (SLM). The heat treatment process was Solution Heat Treatment (SHT, 525 °C), and the heat treatment time includes 1 h, 2 h, and 3 h. Cooling methods consist of Refrigerant Cooling (RC), Water Cooling (WC), Air Cooling (AC), Oil Cooling (OC), and Furnace Cooling (FC). As the cooling rate decreases and the heat treatment time increases, the size of the formed Si phase particles varies from small to large, and the distribution deviates from inhomogeneous to homogeneous. In addition, the number of precipitated particles increases and then decreases. To investigate the impact of cooling rates and heat treatment time on the mechanical properties of AlSi10Mg alloys, quasi-static tensile and compression tests were performed. On the other hand, the tensile strength of the heat-treatment samples decreases while the ductility increases, and the Vickers hardness of the samples also decreases with decreasing cooling rate and increasing heat treatment time. The results of the study showed that the cooling rate and heat treatment time of the material had a greater effect on its tensile properties than on its compressive properties. The samples treated at 525 °C - 2 h - AC exhibited the highest tensile and compressive properties. Finally, the analysis of the strengthening mechanism of AlSi10Mg alloys through the presence of Si phase particles of varying sizes was conducted using transmission electron microscopy.

Evolution of mechanical properties and microstructure of selective laser melted AlSi10MgMn alloy with different post heat treatments

This study investigated the effects of various post heat treatments on the mechanical properties and microstructure evolution of an AlSi10MgMn alloy containing 0.5 wt% Mn produced by the selective laser melting process for the first time. The microstructures under different conditions were analyzed using optical microscopy, scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy. In the as-manufactured (F) condition, the alloy exhibited an ultimate tensile strength (UTS) of 486 MPa, a yield strength (YS) of 299 MPa, and an elongation of 10.3 %. After a T5 treatment, the UTS and YS increased to 532 MPa and 386 MPa, respectively, resulting in a remarkable 30 % improvement in YS compared to the F state. The tensile properties achieved by the new alloy were considerably higher than those reported for conventional AlSi10Mg alloys in the F, T5, and T6 conditions. The T5 treatment promoted the precipitation of a large fraction of Si-rich nanoparticles and MgSi-based precipitates without disrupting the Si-rich network. After a T6 treatment, the Si-rich network completely disappeared, and the main strengthening phase was MgSi-based precipitates accompanied by α-Al(Mn,Fe)Si dispersoids induced by the Mn addition. Using microstructure-based constitutive models, the strengthening contributions of various microstructural components to mechanical strength in different processing conditions were analyzed.

Role of TiC on the microstructure, tensile property and thermal stability of laser powder bed fusion fabricated AlSi10Mg alloy

The incorporation of ceramic particles is frequently employed to enhance the printability of high-strength aluminum (Al) alloys in laser powder bed fusion (L-PBF). However, their influence on the long-term thermal stability and elevated temperature mechanical properties of the Al alloy is seldom studied. This study aims to address this gap by investigating the role of micron-sized TiC particles in the microstructure, long-term thermal stability, and elevated temperature tensile properties of an L-PBF-fabricated AlSi10Mg alloy. The results indicate that highly dense TiC/AlSi10Mg samples can be fabricated, featuring fine equiaxed grains rather than the coarse columnar grains typically formed in the AlSi10Mg alloy. This columnar-to-equiaxed transition is attributed to the residual TiC and the in-situ formation of Al3Ti particles, which act as nucleating agents. Moreover, the incorporation of TiC significantly enhances the long-term thermal stability of the AlSi10Mg alloy by improving the stability of the eutectic network and retarding the coarsening of Si particles by inhibiting Si diffusion. Compared to the AlSi10Mg counterpart, the TiC/AlSi10Mg composite exhibits a higher hardness retention ratio (56 % versus 45 %) after thermal exposure at 400 °C for 192 h. The residual TiC and in-situ formed Al3Ti have high thermal stability and can impede dislocation motion, thereby contributing to enhanced long-term thermal stability. This study offers insights into the design of L-PBF ceramic-reinforced Al alloys with improved thermal stability for high-temperature applications.

The Influence of Post-Treatment on Micropore Evolution and Mechanical Performance in AlSi10Mg Alloy Manufactured by Laser Powder Bed Fusion.

Gas-induced porosity is almost inevitable in additively manufactured aluminum alloys due to the evaporation of low-melting point elements (e.g., Al, Mg, and Zn) and the encapsulation of gases (e.g., hydrogen) during the multiple-phase reaction in the melt pool. These micropores are highly unstable during post-heat treatment at elevated temperatures and greatly affect mechanical properties and service reliability. In this study, the AlSi10Mg samples prepared by LPBF were subjected to solution heat treatment at 560 °C for 0.5 and 2 h, followed by artificial aging at 160 °C, 180 °C and 200 °C, respectively. The defect tolerance of gas porosity and associated damage mechanisms in the as-built and heat treated AlSi10Mg alloy were elucidated using optical, scanning electron microscopic analysis, X-ray micro computed tomography (XCT) and room temperature tensile testing. The results showed the defect tolerance of AlSi10Mg alloy prepared by LPBF was significantly reduced by the artificial aging treatment due to the precipitation of Mg-Si phases. Fracture analysis showed that the cooperation of fine precipitates and coarsened micropores assists nucleation and propagation of microcracks sites due to stress concentration upon tensile deformation and reduces the tensile elongation at break.

Effect of Ultrasonic‐Assisted Treatment on Microstructure and Mechanical Properties of Laser Deposition Repairing AlSi7Mg Alloy

Effect of Ultrasonic‐Assisted Treatment on Microstructure and Mechanical Properties of Laser Deposition Repairing AlSi7Mg Alloy

In-situ laser surface remelting of laser powder bed fused AlSi10Mg alloy at argon and nitrogen protective gases: Multiscale analysis

In the recent decades, laser powder bed fusion (LPBF) of aluminum alloy has been widely used in many fields. However, the poor surface quality, inevitable defects, and limited mechanical performance are obvious obstacles. In-situ laser surface remelting (LSR) is a promising method to give a second opportunity for the defect elimination. In this work, the LSR protective gas (argon and nitrogen) on the surface roughness, porosity, and microstructure of LPBF-fabricated AlSi10Mg alloy are experimentally compared. The nitrogen shows significant superiority in the surface flatness and densification enhancement compared with argon gas. After LSR at nitrogen gas, the average grain size reduces by 8.7 % and the low-angle grain boundaries increases from 70.9 % to 99.7 %. Moreover, a two-dimension mesoscale FEM (Finite Element Method, FEM) model is established to investigate the movement of multi pores inside the molten pool. Attributed to the lower density and dynamic viscosity and larger thermal conductivity, the combination of multi pores is significantly drastic with obvious surface fluctuation during LSR at nitrogen gas. According to the density functional theory (DFT) calculation, the absolute adsorption energies of nitrogen on Al (100) and Al (110) surfaces are generally larger, revealing that the argon gas is easier to be adsorbed on the processing aluminum layer during LSR treatment. Furthermore, the vacancy defects in the aluminum layer play positive roles in the adsorption of gas. This work establishes the importance of the protective gas on the LSR treatment, and provides a multiscale analysis method for the pore evolution.

Mechanism of Grain Refinement in 3D-Printed AlSi10Mg Alloy Subjected to Severe Plastic Deformation.

In this article, the evolution of microstructural characteristics of selectively laser-melted AlSi10Mg alloy subjected to equal channel angular pressing (ECAP) is investigated. The microstructures were analyzed in detail using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission Kikuchi diffraction (TKD), and transmission electron microscopy (TEM). A heterogeneous ultrafine-grained microstructure was produced after one ECAP pass at 100 °C. This microstructure was composed of Al/Si cells and sub-micrometer grains. The grains were refined by conventional dislocation processes; however, evidence of dynamic recrystallization was also documented. Furthermore, it was revealed that the Al/Si cells contribute significantly to grain refinement. EBSD/TKD investigations showed that cell misorientation increased after ECAP processing, resulting in an increased fraction of grains with very low misorientation angles.

Comparative tribological studies of additive manufactured as-built and chemically polished AlSi10Mg alloy surfaces

Comparative tribological studies of additive manufactured as-built and chemically polished AlSi10Mg alloy surfaces

Evaluating the effect of heat input on residual stress, texture and corrosion resistance in friction-stir-welded L-PBF AlSi10Mg alloy

Evaluating the effect of heat input on residual stress, texture and corrosion resistance in friction-stir-welded L-PBF AlSi10Mg alloy

Structure and Mechanical Properties of AlMgSi(Cu) Extrudates Straightened with Dynamic Deformation.

Before artificial ageing, extruded aluminium profiles are subjected to stretching with a small cold deformation in the range of 0.5-2%. This deformation improves the geometrical stability of the extruded product and causes changes in the microstructure of the profile, which leads to the strain hardening of the material after artificial ageing. The work has resulted in the creation of the prototype of an original device, which is unique in the world, for the dynamic stretching of the extruded profiles after quenching. The semi-industrial unit is equipped with a hydraulic system for stretching and a pneumatic system for cold dynamic deformation. The aim of this research paper is to produce advantageous microstructural changes and increase the strength properties of the extruded material. The solution of the dynamic stretching of the profiles after extrusion is a great challenge and an innovation not yet practised. The paper presents the results of microstructural and mechanical investigations carried out on extruded AlMgSi(Cu) alloys quenched on the run-out table of the press, dynamically stretched under different conditions, and artificially aged for T5 temper. Different stretching conditions were applied: a static deformation of 0.5% at a speed of 0.02 m/s, and dynamic deformation of 0.25%, 0.5%, 1%, and 1.5% at speeds of 0.05 and 2 m/s. After the thermomechanical treatment of the profiles, microstructural observations were carried out using an optical microscope (OM) and a scanning electron microscope (SEM). A tensile test was also carried out on the specimens stretched under different conditions. In all the cases, the dynamically stretched profiles showed higher strength properties, especially those deformed at a higher speed of 2 m/s, where the increase in UTS was observed in the range of 7-18% compared to the classical (static) stretching. The microstructure of the dynamically stretched profiles is more homogeneous with a high proportion of fine dispersoids.

Strain rate dependence of mechanical behavior in an AlSi10Mg alloy with different states fabricated by laser powder bed fusion

The strain rate dependence of mechanical behavior in an AlSi10Mg alloy with different states fabricated by laser powder bed fusion (LPBF) was investigated systematically via thermodynamic calculations, microstructure characterization and mechanical characteristic evaluation in the present study. The results show that there is a close relationship among the material state, microstructure and dynamic mechanical behavior. Before tensile deformation, the as-built specimen possesses a fine equiaxed grain structure and a typical cellular structure surrounded by continuously distributed particles; the annealed specimen has coarser equiaxed grain structures and particles, but no cellular structure is present. Both the as-built and annealed specimens exhibit weak strain rate sensitivity, and the strain rate sensitivity parameters are 0.01 and 0.024, respectively. Under specific strain rate conditions, the as-built specimen has a higher strength and lower elongation than the annealed specimen. After tensile deformation, there is a significant increase in the dislocation density. Independent of the material state, the dislocation density increases with increasing strain rate. Compared with the as-built specimen, the annealed specimen has a stronger strain rate sensitivity because of the greater dislocation density variation.

Microstructure and Properties of Deformed AlSi7Mg Alloy

Herein, the effects of hot deformation on the mechanical properties and microstructure of AlSi7Mg alloys were investigated. The microstructure of the alloys with deformation were observed. It can be found that the Si grains of the deformed alloy undergo segregation; however, a suitable heat treatment can be employed to effectively eliminate the segregation. The alloy deformation was 40% at 300 °C, and the mechanical properties of the alloy increased significantly after the heat treatment; the AlFeSi phase was found at the inside of the Si grain and the boundary between eutectic Si and α-Al grains. The AlFeSi phase was found at the inner grain and grain boundaries, and the main strengthening mechanisms of the alloy were precipitation strengthening and deformation strengthening.

Understanding fatigue crack propagation pathways in Additively Manufactured AlSi10Mg

Abstract Alloys produced through additive manufacturing (AM) offer substantial advantages, particularly in controlling material utilisation and precisely manipulating processing parameters, resulting in finely tuned material properties. However, the grain structure of AM material is typically complex, influenced by factors such as solidification dynamics, processing parameters, thermal gradients, and residual stress. Fatigue analysis shows considerable scatter due to entrained defects which limits their use as structural components. In this study, fatigue-failed samples from selective laser melted (SLM) AlSi10Mg alloy, oriented horizontal and vertical to the build direction were analysed to understand crack propagation paths. Here X-ray Computed Tomography (CT) was used to examine internal porosity from which fatigue cracks initiate, complemented by electron backscattered diffraction (EBSD) mapping. This enabled us to recognize the crucial role of the complex grain microstructure in controlling fatigue crack propagation.

Effect of multi-pass shot peening on the microstructure of LPBF AlSi10Mg alloy

Effect of multi-pass shot peening on the microstructure of LPBF AlSi10Mg alloy

Challenges in characterizing additively manufactured AlSi10Mg using X-ray Laue micro-beam diffraction

Abstract Additive manufacturing of metals using for example laser powder bed fusion systems generally results in grains of complex shapes with cellular structure of submicron sizes, accompanied by a high dislocation density. This paper presents preliminary results from characterizing an AlSi10Mg alloy manufactured by L-PBF using non-destructive three-dimensional X-ray Laue micro-beam diffraction. Both synchrotron and laboratory X-ray methods are used. The aim is to identify challenges in characterizing these microstructural features and to propose future research directions to address them.

Thermal Analysis of ALSI10MG Alloy and Heat Treatment Hardening

Thermal Analysis of ALSI10MG Alloy and Heat Treatment Hardening

Synthesis of an Ultra-high Hardness Nanostructured AlSi10Mg Alloy via A Hybrid Laser Powder Bed Fusion/High-Pressure Torsion Approach

The hybrid combination of laser powder bed fusion (L-PBF) and high-pressure torsion, respectively an additive manufacturing (AM) and severe plastic deformation (SPD) has recently emerged as an important field of study due to the ability to produce novel nanostructured metals/alloys with simultaneous enhancements in mechanical (hardness, yield and tensile strengths) and functional (corrosion and wear) performances. Pioneering studies on the hybrid L-PBF/HPT approach was focused on 316L stainless steel (316L SS) and AlCuMg alloys due to their widespread engineering applications. AlSi10Mg, an alloy widely used in the automotive industry is expected to benefit from this hybrid combination but has not been investigated before. Thus, this study aims to investigate the microstructural features and hardness of the nanostructured AlSi10Mg attained by the hybrid L-PBF/HPT technique via transmission electron microscopy (TEM) and Vickers microhardness (HV) measurements, respectively. The results showed novel microstructures, including nano-scale grain sizes (< 200 nm), nano-sized Mg2Si precipitates (~200 nm), and dense dislocation networks. The average hardness value was determined as 230 ± 20 HV, homogeneously distributed throughout the disk surface as indicated by the low deviation (error bar). The microstructures of L-PBF/HPT-synthesised AlSi10Mg are different and significantly refined than conventionally cast AlSi10Mg, which contributed to the two- to four-fold hardness (typical HV values of as-cast AlSi10Mg ranges from 60 – 68 HV) increase via grain boundary and dislocation strengthening mechanisms.

Effects of Building Direction, Process Parameters and Border Scanning on the Mechanical Properties of Laser Powder Bed Fusion AlSi10Mg.

The variability arising from the LPBF process, the multitude of manufacturing parameters available, and the intrinsic anisotropy of the process, which causes different mechanical properties in distinct building directions, result in a wide range of variables that must be considered when designing industrial parts. To understand the effect of these variables on the LPBF manufacturing process, the performance of the AlSi10Mg alloy produced through this technique has been tested through several mechanical tests, including hardness, tensile, shear, and fracture toughness. The results have been correlated with the microstructure, together with manufacturing parameters, building directions, border scanning strategy, and layer height. Significant differences were observed for each mechanical behavior depending on the configuration tested. As a result, an anisotropic material model has been developed from tested samples, which allows to numerically model the alloy and is unique in the current literature.

Multimodal and Correlated STEM Analysis to Generate Stress Maps of Additive Manufactured AlSi10Mg Alloy

Multimodal and Correlated STEM Analysis to Generate Stress Maps of Additive Manufactured AlSi10Mg Alloy

Balloonless spinning spindle head shape optimisation

Abstract The article presents a procedure for assessing and selecting the shape of the ring spinner spindle head that is optimum for yarn manufacturing using the balloonless system, considering multiple criteria. This procedure consists of two stages: the Pareto-optimal method and the distance function method. Twelve spindle head variants were designed and manufactured of 100Cr6 bearing steel composed of C (0.93–1.05%), Si (0.15–0.35%), Mn (0.25–0.45%) along with aluminium alloys EN AW-6060 (AlSi1MgMn) containing Si (0.70–1.3%), Mg (0.6–1.2%), Mn (0.4–1.0%) and EN AW-6060 (AlMgSi) containing Si (0.30–0.60%) and Mg (0.35–0.60%). The shapes of the heads were developed on the basis of the design solutions used previously by the leading ring-spinning machine and spinning spindle manufacturers. Four design variants of spindle heads, made of AlMgSi wrought aluminium alloy, have a unique shape that enables shaping their teeth (notches) by extrusion on a hydraulic press. The assessment criteria were production cost per unit, head weight, maximum surface hardness HV0.1, and four yarn technological quality criteria: maximum yarn tension values during the formation of the base, body and head of the package, and the tension amplitude. The assessment values for the criteria obtained through calculations and measurements were normalized. Then, a set of Pareto-optimal solutions was determined using seven criteria. Due to the fact that this set consisted of six variants, the distance function was used to select the best one. The best design variant of the head is the one corresponding to the lowest distance function value. In our case, the variant is a unique shape, made of AlMgSi alloy, with teeth thickened on the outer diameter of the head, ensuring the lowest yarn tension value at the height during the formation of the package.