Coarse Si Particles Research Articles

High-pressure-torsion-induced segregation, precipitation and grain refinement of Al-(Si, Mg and Cu) binary alloys

To uncover the effects of segregation and precipitation on grain refinement of metals under severe plastic deformation, high-pressure-torsion (HPT) processing is performed on three binary Al-(Si, Mg, and Cu) alloys with different stability and segregation characteristics. Atom probe tomography analysis reveals that HPT processing induces significant decomposition of Al-1 at% Si and Al-1 at% Cu alloys with coarse Si particles and fine Al2Cu (θ) precipitates formed, but no decomposition of Al-1 at% Mg alloy, with dislocations segregated with Si, Cu, and Mg, and grain boundaries (GBs) only segregated with Cu and Mg. The GB segregation of Cu is stronger than that of Mg and Si, with Cu excess in the range of 1.5–7.0 atoms/nm2, Mg excess in the range of 0–4.0 atoms/nm2, but no Si excess. Interestingly, some GBs without Mg segregation develop a Mg-depletion zone along a single side. All evidences demonstrate that GB segregation and precipitation are responsible for HPT-induced grain refinement of Al-1Mg and Al-1Cu alloys but coarsening of the Al-1Si alloy. Engineering solute distribution is of significance in controlling the ultrafine grain of the Al alloys.

Effect of heat treatment on microstructure and mechanical properties of AlSi10Mg fabricated using laser powder bed fusion

Thermal heat treatment is an important step in many metal additive manufacturing processes, particularly laser powder bed fusion (PBF-LB), as it can homogenize the microstructure and enhance the properties of the resulting parts. The effects of post-processing via direct ageing (DA), stress-relieving (SR), and DA or SA followed by annealing or hot isostatic pressing (HIP), on the microstructure, porosity, and resultant mechanical properties of AlSi10Mg samples manufactured using PBF-LB were investigated in this study. Samples were fabricated over a range of processing conditions to probe different starting microstructures and pore features. Porosity and sub-grain solidification cells were characterized because these features are known to influence strength, ductility, and microhardness. DA increased strength at the expense of ductility due to the precipitation of Si-rich particles while SR improved ductility at the expense of strength due to the broken Al/Si eutectic microstructure. Subsequent annealing of DA samples resulted in further breakdown of the Al/Si eutectic microstructure as well as coarsening of Si-rich precipitates, resulting in lower strength and higher ductility than DA alone. HIP resulted in near fully dense and homogenized samples with coarse Si particles, significantly increasing elongation over all other heat treatments. This study shows that processing parameters and heat treatments can be used to tailor porosity, cell size, and resultant mechanical properties of PBF-LB AlSi10Mg.

Corrosion Behaviour of Recycled Aluminium AlSi9Cu3(Fe) Machining Chips by Hot Extrusion and Thixoforming

The corrosion properties of an EN AC AlSi9Cu3(Fe) alloy (reference sample (RS)) and samples produced by recycling chips of RS by direct hot extrusion (DHES) and subsequent thixoforming (TFS) were tested in 0.5 M NaCl solution. The plastic deformation changes the microstructure of RS, and brittle, coarse Si particles and intermetallic compounds (IMCs) were effectively broken into ultrafine-grained particles and redistributed homogeneously into the α-Al matrix in DHES. TFS exhibits a globular structure, and polyhedral clusters rich in Si and IMCs were observed along the grain boundary. Electrochemical measurements combined with surface characterisation show that the microstructure significantly influences the tested samples’ corrosive properties. It was confirmed that corrosion resistance increased in the following order: RS < TFS < DHES. Similarly, the corrosion potential becomes nobler, the corrosion current decreases, the passive area increases, and the oxide layer becomes more stable (higher resistance and thickness). Also, the percentage of the surface affected by corrosion and the volume of pits reduce. The effect of microstructure is particularly pronounced in the level of the corrosion current and the volume of pits formed. The corrosion current of DHES and TFS decreases by 4–5 times, while the pit volume of DHES and TFS decreases by several orders of magnitude compared to RS. The corrosion stability of DHES and TFS in relation to RS is a consequence of the comminution of the Si particles and the IMC. The refined and homogeneous microstructure contributes positively to forming a stable oxide film on DHES and TFS and increases their corrosion resistance in an aggressive environment. The applied recycling method represents an innovative and sustainable process for the recycling of semisolid materials, with lower energy consumption and less greenhouse gas emissions compared to conventional recycling. The fact that the products obtained through recycling have a significantly higher corrosion resistance further increases the economic and environmental impact of the process.

Stimulating adequate strengthening effect through alloying regulation for powder metallurgy CNTs reinforced aluminum matrix composites

Carbon nanotubes (CNTs) reinforced aluminum matrix composites (AMCs) have light weight and high specific strength, showing great potentials for making key structural components in aerospace and transportation industries. Aiming to address the bottleneck problem of unsatisfactory strengthening effect caused by the weak intrinsic interface and adverse interface reaction between CNTs and Al matrix, Si alloying element was added into Al-CNTs system via powder metallurgy method in this study. It was found that the introduction of Si element led to an inhibitory effect on Al-CNTs interface reaction. The discontinuous Al/Si/CNTs composite interface formed by the precipitation of Si significantly improved the wettability of Al/CNTs interface and enhanced its interface bonding through the pinning effect of Si particles, effectively promoting the full play of the load-bearing effect of CNTs. Furthermore, Si particles were effectively refined and passivated through appropriate heat treatment, which facilitated its dispersion strengthening and dislocation strengthening effect, and significantly reduced cracks of coarse Si particles. As a result, the synergistic strengthening effect of CNTs and micro-nano Si particles was significantly exerted in AMCs, remarkably improving the performance of Al–Si-CNTs composites.

On microstructure and work hardening behavior of laser powder bed fused Al-Cu-Mg-Ag-TiB2 and AlSi10Mg alloys

In this paper, we investigate the correlation between microstructure and mechanical properties, including work hardening rates of two aluminum alloys, Al-Cu-Mg-Ag-TiB2 (A205) and AlSi10Mg, both additively manufactured using laser powder-bed fusion (LPBF) technique. Solutionizing followed by over-aging (T7) and artificial aging (T6) heat treatments were performed on as-built specimens of A205 and AlSi10Mg alloys, respectively, to investigate and compare the evolution of microstructure and tensile properties. Tensile tests based on ASTM E8/E8M standard were performed systematically on both materials in both as-built and heat-treated conditions. High-magnification microstructural characterizations including scanning electron and transmission electron microscopies and electron backscattered diffraction were performed to identify the microstructure-property correlations. The A205 alloy contains an ultrafine uniform equiaxed grain structure with no cell and/or epitaxial growth structure. However, the AlSi10Mg contains a cellular microstructure of primary α‐Al cells surrounded by a continuous cellular Si network. Tensile results on A205 (as-built) revealed discontinuous yielding, while the A205 (T7 HT) material serrated plastic flow instability. T7 heat treatment resulted in a 42.4% and 38% increase in yield stress (YS) and ultimate tensile strength (UTS), respectively, and elongation decreased from 12.5% to 9.5% consequently. However, considerable grain growth, coarsening of Si particles, and dissolution of some Mg2Si phases through solutionizing and T6 aging on AlSi10Mg resulted in increased elongation (5.49–14.20%) and decreased YS and UTS (14.5% and 19.4% respectively). The effect of distinct microstructural features of A205 and AlSi10Mg in as-built condition and their evolution in opposite directions upon aging (in terms of mechanical properties) is reflected in their work-hardening behavior. Considerably higher work hardening of AlSi10Mg alloy in both as-built and aged conditions compared to A205 is linked with the cellular structure containing hard eutectic-Si particles at the cell boundaries.

Synthesis mechanism of α-Si3N4 whiskers via SiO vapor in reaction bonded Si3N4-SiC composite

An indirect nitridation mechanism was designed to realize a high conversion rate to α-Si3N4 whiskers in reaction bonded Si3N4-SiC composite via VS mechanism, in which the dominant vapor-phase source of reactants is SiO vapor produced by the active oxidation of Si. The role played by the temperature-time program and addition of ultra-fine Si powder on the formation of SiO vapor and the resulting Si3N4 whiskers was clarified based on the experimental results and the thermodynamic calculations. The result shows that during sintering, in the presence of trace O2, ultra-fine Si particles preferentially undergo active oxidation and volatilized completely in the form of SiO(g). While an equilibrium of SiO(g) and Si(s) is formed on the surface of the coarse Si particle meanwhile. By stepped holding temperature further, this equilibrium is constantly upgraded, so the coarse Si particles is evaporated as SiO(g) shell layer by layer. Massive α-Si3N4 whiskers is formed by SiO(g) nitridation while the stepped holding temperature sintering. A reasonable model of the controllable indirect nitridation mechanism was established.

Effect of growth orientation and heat treatment on the corrosion properties of AlSi10Mg alloy produced by additive manufacturing

Hypoeutectic Al–Si alloys are widely used due to its excellent castability, corrosion resistance and mechanical properties. Its corrosion resistance is limited by the presence of coarse Si particles. Additive Manufacturing (AM) processes is a powerful alternative to overcome such problems. Although mechanical properties of samples produced by AM have been extensively researched, corrosion resistance has received much less attention. In the present paper, Selective Laser Melting (SLM) was used to obtain cubes of AlSi10Mg using two different growth strategies. Corrosion properties are compared both the stress relief thermal treatment and the growth strategy for the manufacturing of the alloy.

Creep properties and microstructure evolution at 260–300 °C of AlSi10Mg manufactured via laser powder-bed fusion

The aging behavior and creep resistance of eutectic AlSi10Mg (Al–10Si-0.6Mg, wt.%) manufactured by laser powder bed fusion (L-PBF) are studied at 260 and 300 °C. The Si phase, which forms a fine interconnected network of 100–200 nm filaments in the as-printed alloy, coarsens into blocky, 2–3 μm particles after 1 month exposure at 260 and 300 °C, with hardness decreasing following a power-law with exponent n = 0.06–0.08. AlSi10Mg with ∼1 μm Si particles (achieved by aging at 300 °C for 96 h) exhibits creep resistance at 260 and 300 °C, for test durations of a few days, comparable to those of (i) cast alloys: hypereutectic Al–Si alloys with coarse Si particles and eutectic Al–Ce, Al–Ce–Ni with much finer, and more coarsening-resistant eutectics phases (e.g., Al11Ce3, Al3Ni); and (ii) L-PBF Al–Mg–Zr alloys. At 260 and 300 °C, our L-PBF AlSi10Mg shows a power-law creep behavior with high apparent stress exponents (na = 10–13, higher than n = 4.0 for Al–Mg) for strain rates between ∼10−8 and ∼10−4 s−1. Also, a high apparent creep activation energy Qa = 256 kJ/mol is measured between 200 and 320 °C at 45 MPa, compared to Q = 142 kJ/mol for Al. These high apparent stress exponent and activation energy are consistent with power-law dislocation creep with a threshold stress, originating from load-transfer from the creeping Al(Mg) matrix to non-creeping Si particles.

In situ alloying of AlSi10Mg-5 wt% Ni through laser powder bed fusion and subsequent heat treatment

In the current study, the effect of in-situ alloying of AlSi10Mg with 5 wt% Ni (pseudoeutectic composition) through the LPBF additive manufacturing technique was investigated. Fabricated samples underwent supplementary annealing treatment at 300 °C for 15 and 120 min, eventually. During the thermal treatment, the fish-scale grains created after printing inside the melt pools after printing vanished gradually. In the as-built sample, molten Ni particles settled as big chunks of Al3Ni in the center and a thin strip of tiny Ni-rich masses in the borders of the melt pools. FIB/SEM and AFM images revealed that after 15 min annealing, silicon cellular dendrites fragment into fine Si particles, and during annealing for 120 min, the aluminum matrix expels out the supersaturated solute silicon atoms. Consequently, Si atoms leave the substrate and diffuse to pre-existing Si particles in cell walls and the triple junctions. Such a collective diffusion of Si atoms leads to the formation of coarse Si particles widespread in the Al matrix. Based on the XRD outputs, annealing for 15 min had not any major effect on Ni-rich phases. however after 120 min, a more brittle intermetallic shell of a Ni-rich phase formed on pre-exist coarse phases. The comparison of the mechanical properties of the Ni-reinforced AlSi10Mg alloy with those reinforced via the addition of other elements/compounds revealed that in a size range close to AlSi10Mg particles, Ni could not be an appropriate candidate for in-situ alloying through the LPBF method. Furthermore, spheroidization of the silicon particles and formation of fragile Ni-rich intermetallic shells having weak interfacial bonding to the Al matrix during the long-term annealing results in a significant reduction in mechanical strength of the specimens.

Effects of processing parameters and post-process heat treatment on selective laser melted SiC/AlSi10Mg composites

In this letter, SiC/AlSi10Mg composites have been fabricated under different selective laser melting (SLM) processing parameters, and then heat-treated for the microstructure and property tailoring. The resulted effects on densification responses, phase constituents, microstructure evolution and mechanical properties of the SiC/AlSi10Mg composites are analyzed and discussed in detail. The results showed that the highest densification and tensile strength were achieved due to the precipitation hardening of Si and Mg2Si, dispersion strengthening of SiC and solid-solution strengthening of α-Al. After kept at 300 °C for 2 h, the ductility of the sample improved significantly with certain sacrifice of tensile strength due to the precipitation of β-Al4.5FeSi, coarsening of Si particles and weakened solid-solution effects from supersaturated α-Al.

Hot dwell-fatigue behaviour of additively manufactured AlSi10Mg alloy: Relaxation, cyclic softening and fracture mechanisms

This paper presents the results of high temperature strain-range controlled low cycle fatigue tests of a laser powder bead fused AlSi10Mg alloy. Following stress relief (2hrs at 300 ℃), two cyclic loading waveforms (standard triangular and dwell-type trapezoidal waveforms) and three temperatures (100 ℃, 250 ℃ and 400 ℃) were applied to investigate both the mechanical response and the related microstructural changes of this additively manufactured (AM) aluminium alloy. The bulk mechanical responses were found to exhibit a continuous cyclic softening, decreasing stress relaxation and decreased energy dissipated per cycle. The stress relaxation is strongly affected by the test temperature rising to almost complete relaxation at 400 ℃. At lower temperatures (100 ℃ and 250 ℃), the higher the temperature the more subgrains are developed during cyclic loading. Up to 250 ℃, the subgrain size increases with temperature and laser powder bead fused defects preferentially act as the fatigue crack initiation sites. While at 400 ℃, coarse Si particles precipitate during cyclic deformation and a high density of microvoids are nucleated from these coarse Si precipitates, which grow and link up to cause failure, resulting in a dimple dominated ductile fracture.

A comparative study of tensile properties of eutectic Al-Si / ZrO2 composites fabricated by spray forming and stir casting methods

ABSTRACT The study aims to investigate the microstructural and mechanical properties of Al-12.5%Si matrix composites reinforced with ZrO2 were fabricated by spray forming method and stir casting (SC) technique by varying reinforcement of 2%, 6% and 10 wt.% ZrO2 powder (size 25 μm).The spray-formed (SD) composites were subjected to hot (400°C) isostatic pressing to reduce the porosity. The microstructure of spray-formed and SC composites were examined using optical and SEM/ EDS. The microstructure of the spray-formed composites showed uniform distribution of fine Si, eutectic phase and ZrO2 particles in the equiaxed Al-matrix. In contrast, SC composites consist of a coarse Si, needle like eutectic phase and clustering of reinforcement particles at grain junctions as a continuous network along the grain boundaries. The hardness, ultimate tensile strength of both spray-formed and SC composites improved as the ZrO2 content increased, while yield strength decreased. Spray-formed composites showed better mechanical properties. This was attributed to uniform distribution fine of Si particles, reinforced particles, equiaxed matrix induced during spray deposition process. Tensile fracture surface of spray-formed composites possess ductile and cleavage fractures. SC composites showed intragranular cracks in coarse Si particles and increase in micro-cracks with increasing reinforcement.

Microstructural evolution, dislocation density and tensile properties of Al–6.5Si–2.1Cu–0.35Mg alloy produced by different casting processes

Al–Si–Cu–Mg foundry alloys are used in casting process technologies. However, their strength properties remain low due to their microstructural characteristics and porosity. In this work, the microstructural characteristics, dislocation densities, and mechanical properties of Al–Si–Cu–Mg cast alloys prepared through different casting methods were studied experimentally. Four casting processes, namely, gravity casting (GC), rheocasting (RC), thixoforming (Thixo), and Thixo with heat treatment, were used. The GC and RC samples had mainly dendritic α-Al phase microstructures and exhibited coarse Si particles and intermetallic compounds in their interdendritic regions. By contrast, the Thixo and heat-treated Thixo (HT-Thixo) samples exhibited microstructural refinement with uniformly distributed α-Al globules, fine fibrous Si particles, and fragmented intermetallic compounds among α-Al globules. The accumulation of dislocation densities increased in the Thixo sample as the strain was increased due to plastic deformation. Furthermore, the ultimate tensile strength and yield strength of the HT-Thixo sample increased by 87% and 63%, respectively, relative to those of the GC sample. The cleavage fracture displayed by the GC and RC samples led to brittle failure. Meanwhile, the Thixo and HT-Thixo samples presented dimple-based ductile fracture.

Investigating the role of Cu, Zr and V on the evolution of microstructure and properties of Al-Si-Mg cast alloys

Understanding the evolution of as-cast microstructure (especially eutectic Si and intermetallics) in Al-Si-Mg alloys is critical for improving the mechanical properties because they could be beneficial or detrimental depending on their size, morphology, and distribution. In this study, the effects of transition metal elements Cu, Zr, and V on the microstructure and mechanical properties of Al-Si-Mg cast alloys were investigated. It was found that the addition of Cu reduced the secondary dendrite arm spacing (SDAS) and led to the formation of coarse Si particles. However, SDAS was further refined when Zr and V were added. The yield tensile strength and ultimate tensile strength of Al-Si-Mg cast alloy was increased when Cu was added due to the solid solution and the decrease of SDAS, while additions of Zr and V led to the significant reduction in ductility and ultimate tensile strength of the Al-Si-Cu-Mg alloy due to the needle-shaped phases (Zr-Ti-V-containing phase). Such particles promoted stress concentration, leading to early fracture and reduced ductility.

Spheroidization and Coarsening of Eutectic Si Particles in Al‐Si‐Based Alloys

The present study was carried out on three Al‐Si cast alloys viz., 319, 356, and 413 alloys, solidified at 8°C/s. Samples from 319 and 413 alloys were solution heat‐treated at 510°C, whereas samples from 356 alloy were solutionized at 550°C, for up to 1200 h. The results reveal that complete spheroidization of eutectic Si particles in terms of achieving individual spherical particles cannot be achieved in most Al‐Si‐Cu‐Mg alloys even after a solutionizing time of 1200 h which contradicts with the existing theory. Addition of Sr to Cu‐free 356 alloy could lead to complete spheroidization after 1200 h at 550°C if the alloy was solidified at 8°C/s. Besides the dissolution theory of Ostwald, coarsening of Si particles can as well take place by impingement, fusion, and agglomeration. Increasing the Si content makes it difficult to achieve spheroidization, i.e., fragmentation and coarsening. Results obtained from observations of deeply etched samples (3D) contradict those obtained from polished samples (2D).

Tribological behavior of friction stir processed SiP/ZA40 in-situ composites

Abstract The effect of friction stir processing (FSP) at different rotation speeds (400, 630, 800, and 1000 r/min) and traverse speeds (25 and 50 mm/min) on the tribological properties of a Si particle reinforced Zn−40Al−2Cu-based in-situ composite was investigated. After preliminary optimization, 800 r/min and 25 mm/min were selected as optimum FSP parameters. According to the results, multi-pass FSP improved the tribological properties. For instance, at an applied pressure of 0.75 MPa, the wear rate and average coefficient of friction (COF) of four-pass FSPed composite were lower than those of base composite by 53% and 50%, respectively. SEM examinations of worn surfaces, wear debris, and worn subsurfaces revealed that the intensive refinement and uniform distribution of microstructural phases, especially the coarse Si particles, reduced Si particles interspacing, and elimination of casting defects were the most important factors enhancing the substrate resistance against sliding-induced deformation. This led to the formation of stable tribolayers that improved the tribological properties.

Effects of zinc content on strength and wear performance of Al−12Si−3Cu based alloy

Abstract The effects of Zn content on strength and wear performance of Al−12Si−3Cu alloy synthesized by gravity casting were systematically investigated. The microstructure and mechanical properties of the alloys were evaluated using OM, XRD, SEM as well as hardness, tension, compression and Charpy impact tests. Their dry sliding wear tests were carried out with a ball-on-disk tester. Microscopic examinations revealed that the microstructure of the base alloy consisted of the α(Al) dendrites, needle-type and coarse Si particles, and CuAl2 (θ) phase. The addition of Zn to this alloy resulted in the formation of α-solid solution phase and the increase of coarse Si particles. The hardness, yield, tensile and compressive strengths, elongation to fracture and impact toughness of the Al−12Si−3Cu−Zn alloys increased with increasing Zn content, but tendency in the tensile and compressive strengths and ductility reversed after adding 1.5%−2% Zn. In addition, the friction coefficient and volume loss of the Al−12Si−3Cu−Zn alloys decreased with increasing Zn content. The study showed that the addition of Zn to Al−12Si−3Cu alloy can improve its potential applications as tribological material.

On microstructure and early stage corrosion performance of heat treated direct metal laser sintered AlSi10Mg

This study examines the impact of low-temperature heat-treatment on the microstructure and corrosion performance of direct metal laser sintered (DMLS)-AlSi10Mg alloy. Differential scanning calorimetry (DSC) was used to determine the phase(s) transition temperatures in the alloy. Two exothermic phenomena were detected and associated with the Mg2Si precipitation and Si phase precipitation in the as-printed alloy. Based on DSC results, thermal-treatments including below and above the active Si precipitation temperature at 200 °C and 300 °C, respectively, and 350 °C as an upper limit temperature for 3 h were applied to the as-printed samples. Scanning electron microscopy and X-ray diffraction analysis confirmed that heat-treatment from 200 °C to 350 °C promotes the homogeneity of the microstructure, characterized by uniform distribution of eutectic Si in α-Al matrix. To investigate the impact of the applied heat-treatment cycles on corrosion resistance of DMLS-AlSi10Mg at early stage of immersion, anodic polarization testing and electrochemical impedance spectroscopy were performed in aerated 3.5 wt.% NaCl solution. The results revealed more uniformly distributed pitting attack on the corroded surfaces by increasing the heat-treatment temperature up to 300 °C, attributed to the more protective nature of the spontaneously air-formed passive layer on the surface of the alloy at initial immersion time. Further increase of the heat treatment temperature to 350 °C induced severe localized corrosion attacks near the coarse Si particles, ascribed to the increased potential difference between the coalesced Si particles and aluminum matrix galvanic couple. In comparison, the corrosion of the as-printed and 200 °C heat treated samples was characterized by a penetrating selective attack along the melt pool boundaries, leading to a higher corrosion current density and an active surface at early exposure, associated with the weakness of the existing passive film on their surfaces.

Ultrasonication Effects on the Microstructure Characteristics of the A380 Die Cast Alloy

This investigation is an attempt to optimize the ultrasonic treatment (UST) temperature to refine the microstructure of A380 diecastings. As a preliminary estimation, isothermal UST was performed at the liquidus temperature, slightly above and at elevated temperature. This was followed by filling in a permanent mold. The ultrasonic vibrations were also applied to A380 at the same temperatures before being injected into the shot sleeve for diecasting. It was observed that in the isothermal treatment of both grain-refined and ungrain-refined alloys the UST at 600 °C and 595 °C changed the microstructure to a much finer and non-dendritic compared to UST at 620 °C. The effect was higher in the grain-refined alloy where Fe-phase transformed to a more globular form with UST at 600 °C and 595 °C. In case of diecasting without ultrasonic, coarse Si particles and massive Fe-intermetallics were observed. Applying UST to the melt of grain-refined alloy at high pouring temperatures (700 and 670 °C) did not show substantial effects on either Fe-intermetallics or Si particles. On the other hand, the grain-refined A380 alloy showed much finer grain sizes, highly globular Fe-phase and modified Si particles when UST is at lower pouring temperatures (640 and 620 °C). However, at pouring temperature of 675 °C, the unrefined alloy showed some grain refining while no effects on Fe-particles were observed.

Aluminium Matrix Composites Produced by Laser Based Additive Manufacturing

3D laser metal deposition (LMD) based on the laser cladding is an established technique for additive manufacturing tasks. Also the laser cladding is a well-known technique to produce aluminum matrix composites reinforced by Si particles. High cooling rates typical for laser treatment enable to eliminate coarse Si particles formation which is a substantial disadvantage of in-situ Al-Si composites produced by traditional manufacturing processes like casting. The coarse Si particles formation reduces Al-Si composites mechanical properties. Extremely non-equilibrium solidification conditions typical for micro LMD process allow to obtain a further structure refinement and its mechanical properties improvement. In this paper the in-situ Al-Si composites produced by micro LMD process with different parameters sets were investigated by fine structure X-ray analysis. The structure and phase composition of in-situ Al-Si composites were described. The influence of cladding parameters on Al-Si composites structure was investigated.