As-cast Samples Research Articles

Local lattice distortions, phase stability, and mechanical properties of NbMoTaWHfx alloys: A combined theoretical and experimental study

Refractory high-entropy alloys (RHEAs) are of growing interest due to their potentially superior mechanical performances at elevated temperatures. Inherent lattice distortions are believed to be a major contributor to strength in solid solution phases of RHEAs. Here, we investigate the NbMoTaWHfx alloy series (x = 0, 0.27, 0.57, 0.92, 1.33, 1.82) using first-principles simulations, thermodynamic modeling, and experimental techniques. The first-principles results suggest that Hf alloying is an effective means to enhance atomic-scale lattice distortions in BCC NbMoTaWHfx solid solutions. X-ray diffraction on prepared as-cast samples shows that the alloys with Hf content x≤0.92 are single phase BCC alloys, whereas a dual BCC phase microstructure is observed for x = 1.33 and 1.82. Elemental mappings from scanning electron microscopy for the dual-phase alloys are checked with predictions from thermodynamic modeling for equilibrium and non-equilibrium solidifications. Room-temperature compressive mechanical tests reveal that yield and ultimate strengths increase strongly with the addition of Hf and saturate for x>0.92, whereas the compressive plasticity is slightly improved by Hf but remains limited. We predict the compositional effects on poly-crystal elastic moduli for the constituent BCC phases and the dual-phase composites and find a linear behavior between modulus-normalized yield strength and lattice distortion on average.

Effect of cerium on microstructure, texture and properties of ultrahigh-purity copper

The effects of Ce addition (310 ppm and 1500 ppm) on the microstructure, texture and properties of ultrahigh-purity copper (99.99999%) were systematically studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD) analyses, combined with the microhardness and conductivity tests. Regarding the microstructure of the as-cast and as-extruded samples, the addition of Ce refines the grain size of the ultrahigh-purity copper and the refinement effect of 310Ce alloy is greater than that of 1500Ce alloy. This is due to the stronger component supercooling and the accelerated recrystallization caused by lower Ce content. In addition, Ce can react with Cu to form the Cu–Ce eutectic phases, which are deformable during the hot deformation. Furthermore, the added Ce can weaken the texture, showing a variation of brass recrystallization (BR), rotated cube, copper and S texture components, which depends on the recrystallization, the particle stimulated nucleation (PSN) as well as the stacking fault energy (SFE). Most remarkably, the introduction of Ce enhances the hardness of the ultrahigh-purity copper without obviously reducing its conductivity. The major {111} orientations and the stress distributions are responsible for such a superior conductivity of the Ce-containing alloys.

The Impact of Plastic Deformation on the Microstructure and Tensile Strength of Haynes 282 Nickel Superalloy Produced by DMLS and Casting.

The article presents the results of research on the influence of plastic deformation on the microstructure and tensile strength of Haynes 282 nickel superalloy produced by direct metal laser sintering (DMLS) and a conventional technique (casting). Samples were tested for dimensional accuracy using a 3D scanner. Then, the samples were subjected to plastic deformation by rolling. The microstructures of the DMLS and the as-cast samples were analysed using a scanning electron microscope. The strength properties of the samples were determined in a static tensile test. Microhardness measurements of the samples were also performed. Based on the analysis of the dimensional accuracy, it was found that the surface quality of the components produced by DMLS is dependent on the input parameters of the 3D printing process. Using the DMLS method, it is possible to produce Haynes 282 with a fine-crystalline microstructure containing dendrites. The fine-crystalline dendritic microstructure and low porosity showed very good tensile strength compared to the as-cast material. It was also found that the increase in the degree of plastic deformation of the as-cast Haynes 282 and the samples produced by the DMLS technique resulted in an increase in the strength of the tested samples, with reduced ductility.

Rejuvenation by compressive elasto-static loading: The role of static stress on a Zr-based metallic glass

Calorimetric, mechanical, and microstructural characterizations are used to investigate the rejuvenation of Zr55Cu30Al10Ni5 (at%) bulk metallic glass (BMG) by elasto-static loading (ESL). The as-cast BMG samples are compressed at room temperature for 24 h while being subjected to static stresses that ranged from 40 %, 70 %, 80 %, and 90 % of the yield stress. The BMG undergoes structural rejuvenation as a result of the compressive ESL treatment, increasing the free volume content at all applied static stresses. The amount of energy that has been stored, as determined by the relaxation exotherms that precede glass transition, appears to be a function of static stress and reaches a maximum of 13.2 J g−1 at the highest applied stress, which is twice the stored energy of the as-cast sample. A steady increase in plastic strain, a decline in hardness, and a fall in Young's modulus are linked to enthalpy rejuvenation of the BMG. According to microstructural investigations, ESL introduces structural heterogeneities into the BMG that are linked to structural dilatation at the short- and medium-range atomic scales. This study emphasizes rejuvenation as the main effect of ESL treatment on the BMG under study.

Anomalous In Vitro Corrosion Behaviour of Rolled Mg-1 wt. % Zn Alloy Due to Buffer-Microstructure Interactions

In this study, the influence of microstructure and buffer system on the corrosion behaviour of Mg-1 wt. % Zn is examined. The grain size of the alloy was refined from 700 µm to under 15 µm by rolling with varying reduction percentages per pass. The effects of the rolling procedure on the resulting corrosion profile were analysed with immersion and electrochemical methods. Though the rolling procedure resulted in significant grain refinement, the as-cast samples had the lowest corrosion rate of 2.8 mm/yr, while those of the rolled samples were as high as 15.8 mm/yr. The HEPES buffer system did not control the pH or support the formation of insoluble precipitates as well as the NaHCO3/CO2 buffer system, leading to more severe localised pitting corrosion in samples immersed in HEPES buffered media. While reducing grain size generally corresponds to a lower corrosion rate in Mg alloys, this study provides evidence that other factors such as texture and buffer system must also be considered to accurately test candidate alloys for biodegradable orthopaedic applications.

Enhanced mechanical properties of Zr65Cu15Ni10Al10 bulk metallic glass by simultaneously introducing surface grooves and multiple shear bands

Recent investigations have demonstrated that the plasticity of bulk metallic glasses (BMGs) at room temperature can be improved by artificially introducing both macroscopic and microscopic defects. In this work, both surface grooves and multiple shear bands (MLSBs) are concurrently introduced into the surface of a Zr65Cu15Ni10Al10 BMG employing an ultrasonic bonding machine, whose sizes are also tailored by tuning gas pressures and times. After surface treatment, MLSBs appear around grooves due to the pre-plastic deformation, while numerous nano-scale crystals resulting from thermal-induced nanocrystallization appear within the grooves, leading to the emergence of hierarchical structural heterogeneities. As a result, the strength and plasticity are effectively enhanced compared to as-cast samples when suitable experimental parameters are adopted. The plastic deformation mechanisms change from single main shear banding to multiple shear banding. Therefore, the serrated plastic behaviors exhibit a transition from chaotic to self-organized critical dynamics after surface treatment, confirming the modification of the shear banding instability. The present study provides a viable method to tailor the mechanical properties of BMGs and sheds light on their dynamic plastic deformation behaviors.

Effects of transient thermal shock on the microstructures and corrosion properties of a reduced activation high-entropy alloy

The devices would subject transient thermal shocks (TTS) during operation under extremely harsh conditions of nuclear fusion reactors, which inevitably exert significant impact on the microstructure and performance of structural materials. In this work, a reduced activation VCrFeTa 0.2 W 0.2 high-entropy alloy (HEA) was developed by vacuum arc melting. The effects of electron beam induced TTS on its microstructure, microhardness, and corrosion properties were investigated. The results indicate that the weight fraction of each phase changes after TTS, showing a significant decrease in the content of BCC1 phase and an increase in the content of BCC2 and Laves phases. The content of BCC1 phase continues to decrease slightly with increasing the power of TTS. Besides, the microhardness of the alloy increases from ~673 HV to ~714 HV after TTS treatments. In the reduced activation HEA, TTS results in a relatively low corrosion current density of ~0.472 μA/cm 2 in 3.5 wt% NaCl solution, around one-third of the current density observed in the as-cast sample. Furthermore, the VCrFeTa 0.2 W 0.2 HEA after TTS exhibits a pitting potential of ~1.165 V SCE , which is much higher than that of the as-cast sample. The refined composite multiscale entropy method is employed to analyze the influence of TTS on current fluctuation behavior during the corrosion process. The reduced activation VCrFeTa 0.2 W 0.2 HEA exhibits excellent properties in harsh environments after TTS, thereby showing advantageous property in the field of nuclear structural materials. Moreover, TTS is an efficient and controllable strategy for the improvement of the HEAs’ microstructures and performances. • A reduced activation VCrFeTa 0.2 W 0.2 high-entropy alloy is developed. • Transient thermal shock is used to change the microstructure. • Microhardness of the alloy increases from ~ 673 HV to ~ 714 HV. • The corrosion resistance of the alloy is improved by transient thermal shock. • Refined composite multiscale entropy method is used to analyze the corrosion behavior.

Dry sliding, slurry abrasion and cavitation erosion of composite layers reinforced by TiC fabricated in situ in cast steel and gray cast iron

To improve the wear resistance of low-carbon steel and gray cast iron, TiC/Fe-type composite layers were fabricated using reactive casting coatings. The in situ synthesis reaction of titanium carbide (TiC) was initiated by the high temperature of the liquid alloy (SHS – self-propagating high-temperature synthesis). The structure, microstructure, hardness, and wear properties of the composite layers were investigated. Wear examinations were carried out in various environments: dry sliding, slurry abrasion, and cavitation erosion in slurry. An observation of the microstructure revealed the presence of TiC particles that were well-bonded with both types of matrices. The mechanical properties showed an almost three-fold increase in the hardness within the area of the composite layer as compared to the base alloy (1000HV1). These results were reflected in a slurry abrasion test that indicated less than half of the weight loss as compared to the monolithic matrix of the composite castings. The cavitation erosion wear mechanism of the composite layers was examined for the first time taking the surface of the sample into consideration (after polishing and as cast – casting skin). The polished surfaces were characterized by higher resistance to cavitation erosion than the as-cast samples. On the other hand, the casting skin acted beneficially as an extra coating that prevented the castings’ cores from cavitation erosion damage. • Composite layers were fabricated in situ in cast steel and cast iron. • Hardness within area of composite zones reached more than 850 HV1. • Composite layers were testes by ball on disc method, Miller test and cavity erosion. • Composite layers were tested in as – cast state and after polishing process.

Novel precipitation strengthened Al-Y-Sc-Er alloy with high mechanical properties, ductility and electrical conductivity produced by different thermomechanical treatments

This study investigated the evolution of the microstructure, mechanical properties, and electrical conductivity of novel Al-0.2Y-0.2Sc-0.3Er alloy in as-cast, as-rolled, and annealed states. Aluminum solid solution and τ2 (Al75–76Er11–17Y7–14) eutectic phase particles with a size of 50–200 nm were identified in the as-cast alloy sample by scanning electron microscopy investigation and phase diagram analyses. A precipitation strengthening mechanism was implemented during annealing at 300 °C for 7 h due to L12 precipitates of Al3(Sc,Y,Er) phase with a maximum diameter of 10 nm. The same structure was formed in the samples annealed at 300 °C for 7 h after rolling the as-cast alloy without aging treatment. The samples aged before rolling formed a more homogenous and finer substructure, with a grain structure formed after annealing rolled sheets. Significantly more uniform structures facilitate achieving higher strength and electrical conductivity. Al-0.2Y-0.2Sc-0.3Er alloy aged at 300 °C for 7 h, hot and cold rolled, and annealed at 300 °C for 7 h exhibited a good combination of strength and electrical conductivity: YS = 191 MPa, UTS = 207 MPa, El. = 14 %, and EC = 59.7 % IACS.

Rejuvenation by enthalpy relaxation in metallic glasses

Structural relaxation can be induced by annealing and usually leads to embrittlement in metallic glasses (MGs). Here, we show that a relaxed MG obtained by annealing an as-cast MG at a temperature (annealing temperature, Ta) below its fictive temperature can be suitably rejuvenated by a thermal treatment of the relaxed MG at a temperature higher than Ta. The effect is driven by enthalpy relaxation, an endothermic reaction upon heating relaxed MG. This rejuvenation lifts the energy state of the relaxed MG towards that of the as-cast MG. Importantly, we found that the plasticity and fracture toughness of the optimally rejuvenated samples exceed those in the as-cast sample, reversing the relaxation-induced embrittlement in the relaxed sample. An analysis of the structural changes shows that the packing density, rather than the ordering of the atomic structure, is responsible for the effects of rejuvenation. The observed rejuvenation may originate from the recovery of loosely packed regions in the MG atomic structure that were densified during annealing. Our findings are significant for tailoring the mechanical properties of MGs.

Microstructure evolution, deformation mechanism, and mechanical properties of biomedical TiZrNb medium entropy alloy processed using equal channel angular pressing

Equal channel angular pressing (ECAP) was applied to a biomedical TiZrNb medium entropy alloy (MEA) with an equal atomic ratio at 480 °C with 1, 2, 4, and 6 deformation passes in route C to enhance the mechanical properties and exploit the plastic deformation mechanism of the MEA. As the applied strain increased, dendritic grains first tended to merge and form equiaxed grains, which eventually elongated and formed coarse grains. Simultaneously, many straight dislocations and dislocation loops occurred and coalesced into a line during the early stages. Then, they rearranged to construct highly dense dislocation walls (HDDWs) and evolved into shear bands, maintaining the continuity of the deformation. After a 6-pass deformation, the TiZrNb MEA exhibited a yield strength of 1170 ± 21 MPa, higher than that of the as-cast sample of 830 ± 21 MPa, and a maximum hardness of 389 ± 11 HV0.2, which enhanced its wear resistance.

Improved corrosion resistance achieved in a friction stir processed Mg-5Zn-0.3Ca alloy with fragmented precipitates

The microstructure of an as-cast Mg-5Zn-0.3Ca alloy was significantly modified by friction stir processing, which improved the alloy’s corrosion resistance. In electrochemical results, the corrosion current density of the FSPed sample at the open circuit potential in 3.5 wt% NaCl aqueous solution decreased to 4.3 μA/cm2 (about 1/7 that of the as-cast sample). The improved corrosion resistance was attributed to the weakening of galvanic corrosion caused by precipitate fragmentation. In addition, a large number of fine cathodic precipitates tended to accumulate on the corroded surface, thereby forming a denser deposition layer and enhancing the shielding effect against corrosion propagation.

Thermal cycles behavior and microstructure of AZ31/SiC composite prepared by stir casting

In the present work, the effect of thermal cycles on the physical and thermal properties of AZ31 alloy and AZ31/5wt%SiC and AZ31/10wt%SiC composites was investigated. Samples were prepared using the stir casting method and then subjected to precipitation hardening. Thermal cycles were done for as-cast and aged samples with V-shaped notch under 300, 600, and 900 heating and cooling cycles at 150 and 350 °C. The crack length (CL) was evaluated using optical microscope (OM), scanning electron microscope (SEM), and energy-dispersive scanning electron (EDS) analysis. Also, density, porosity, thermal expansion coefficient of the samples were evaluated. X-ray diffraction (XRD) analysis was employed to assess the phases present in the material. The results demonstrated that by increasing the number of thermal cycles up to 600 at 150 °C and 350 °C, the porosity and density of the as-cast and aged AZ31 alloy decreased and increased, respectively; however, the density and open porosity were remained constant for the composite samples. The crack's length enlarged with increasing the thermal cycles from 300 to 600 µm at 150 °C and 300 to 900 µm at 350 °C. It was found that the reinforcement and precipitates prevented the rapid growth of the crack in the magnesium matrix. All in All, composite and the aged samples demonstrated better thermal fatigue resistance compared with that of the unreinforced alloy and as-cast samples, respectively.

Ultrasonic-assisted fabrication of metallic glass composites

Metallic glass composites (MGCs) inherit the high strength of their glassy matrix and exhibit remarkable plastic deformation, hence have great potential in engineering applications. However, their preparation often relays on arduous component exploration or involves elusive technological process. Here, we report a facile route to fabricate MGC using ultrasonic vibration (UV) and the fabrication process can be manually controlled. By appropriately modulating the amplitude and time of UV, the MGCs with different proportion of crystalline phase can be obtained readily and accurately in seconds under low-pressure at room temperature owing to the unique soften behavior of MG under UV. The deformation behavior and the hardness were evaluated using nanoindentation testing, demonstrating better ductility when compared with the as-cast sample and reduced hardness for the MGCs as increased proportion of crystalline phase. These results may provide a new approach for the rapid and controllable fabrication of MGCs with designed properties.

Controlling the relaxation versus rejuvenation behavior in Zr-based bulk metallic glasses induced by elastostatic compression

Elastostatic compression (ESC) has received considerable research attention as a tool to study rejuvenation and relaxation processes for bulk metallic glasses (BMGs). However, little is understood about the conditions that control whether rejuvenation or relaxation will occur, and whether conditions exist that can give structural stability. We address these questions by applying ESC at 90% of the yield stress to both cast and laser powder bed fusion (LPBF) manufactured Zr-based BMG samples in the as-cast, as-built, and different annealed states. The structural state and mechanical properties for each material condition were characterized by differential scanning calorimetry and microhardness, respectively, and two representative groups were also used for compression testing. Initial relaxation or rejuvenation was observed for elastostatically compressed as-cast samples, and the behavior reversed over 72 h of ESC. In contrast, no ESC effect was observed for the as-built LPBF samples. It was found that the onset of either relaxation or rejuvenation by ESC could be better predicted if samples were annealed into a controlled initial state. Five different types of initial response to ESC were observed, corresponding to different initial energy state ranges. Materials in the highest and lowest initial energy states were stable against structural changes by ESC. Close to the highest energy state, rejuvenation was dominant, while relaxation took place close to the lowest energy state. At intermediate initial energy states, both relaxation and rejuvenation were observed after ESC loading, suggesting that the glass structure easily finds different local minima in the potential energy landscape. In all cases, relaxation was associated with BMG hardening and rejuvenation was associated with softening. Overall, the results of this study provide new insights into how ESC impacts the structural state and mechanical properties of BMGs.

Effect of Zirconium micro-addition and multi-pass friction stir processing on microstructure and tensile properties of Mg–Zn–Si alloys

The aim of this study is to investigate the microstructure and tensile properties of Mg-0.5Zn-0.2Si-XZr (X: 0, 0.25, 0.5 wt.%) in the as-cast and multi-pass friction stir processed (FSPed) conditions. Micro addition of Zr element resulted in the average grain size (AGS) reduction from 1.65 ± 0.3 mm in Mg-0.5Zn-0.2Si alloy to less than 700 μm through the formation of Zr-rich particles evenly distributed in the structure and constitutional supercooling effect. However, the refinement efficiency of Zr was reduced by the formation of Si-containing intermetallic phases through the Si poisoning effect. Thus, agglomeration of these brittle compounds, specifically at the grain boundaries, resulted in quasi-brittle fracture mode in the as-cast samples. On the other hand, applying the FSP on Zr-free alloy improved both microstructure and mechanical properties due to grain refinement and porosity content reduction. In other words, in the optimum condition, the AGS reduced to about 5 μm and yield strength (YS), ultimate tensile strength (UTS) and total elongation percentage (EL%) improved up to 70%, 90%, and 566%, respectively, compared to the as-cast sample. On the other hand, in the Zr-modified alloys, the fragmentation and even redistribution of Zr-rich and Si-rich phases, particularly after the 2nd FSP pass, enhanced the dynamic recrystallization (DRX) through the particle stimulated nucleation (PSN) mechanism and restricted the grain growth through the Zener pinning effect. Therefore, the AGS of 2 ± 0.1 μm, UTS of 182 Mpa, and EL of 36% were achieved.

Microstructure, mechanical and corrosion properties of biodegradable Zn-Mg-Zr alloys for biomedical applications

• Biodegradable HR Zn-1Mg-xZr alloys are fabricated via alloying and hot-rolling. • HR Zn-1Mg-0.05Zr alloy shows YS of 218.0 MPa, UTS of 263.2 MPa, and EL of 12.1% • Hot-rolling enhances the YS, UTS, and EL due to the dynamic recrystallization. • HR Zn-1Mg-0.05Zr alloy possesses a degradation rate of 71 μm/y in Hanks’ solution. Zn-1Mg-xZr alloys were prepared via alloying with different Zr contents and hot-rolling, and their microstructures, mechanical properties, and corrosion behaviors were assessed systematically. The results indicated that the mechanical strength of as-cast and hot-rolled (HR) samples initially increased and subsequently decreased with increasing Zr addition. HR samples showed a substantial increase in yield strength (YS), ultimate tensile strength (UTS) and elongation (EL) compared with their as-cast counterparts. HR Zn-1Mg-0.05Zr alloy showed higher mechanical property matching (218.0 MPa for YS, 263.2 MPa for UTS, 12.1% for EL) and an appropriate corrosion rate of 455 μm/y in Hanks’ solution among the Zn-1Mg-xZr alloys for biomedical applications.

Rejuvenation behaviors of recovery-annealed Cu–Zr metallic glass with different thermal treatment conditions: a molecular dynamics study

The recovery annealing process, which reheats the relaxed metallic glass (MG) to a certain temperature above glass transition temperature and subsequently rapid quenched, could tailor the sample to a less relaxed state, called as rejuvenation process. During the recovery annealing process, the final cooling rate, isothermal time and annealing temperature all affect the obtained rejuvenated state. In the present study, we investigated the changes of configurational potential energy and atomic structure of Cu–Zr MG under various different parameters by using molecular dynamics simulation. We found that when the final cooling rate after recovery annealing exceeds the cooling rate of the as-cast sample, a transition point from ageing to rejuvenation exists in the annealing temperature ranging from 900 to 1000 K. Meanwhile, the degree of ageing when annealed at 900 K, as well as the degree of rejuvenation when annealed at 1000 K, improves with a longer isothermal time. The transition behavior from ageing to rejuvenation at different annealing temperatures is mainly caused by the variation of proportions of Cu-centered and Zr-centered polyhedra in the supercooled liquid region. This work provides a profound understanding of the change in configurational potential energy and atomic structure during recovery annealing with different thermal parameters.

Measurements of high phase transition temperatures and construction of Ni-Si-Zr phase diagram

There is a hindrance in modeling Gibbs energies of high melting alloys via the CALPHAD approach because of the scarcity of experimental results. All the conventional methods suffer to overcome the practical difficulties at high temperatures. Despite these setbacks, this paper provides a reliable way of using an arc-melting device in conjunction with a pyrometer to measure high-temperature phase transitions and developing a hybrid approach to construct a Ni-Si-Zr phase diagram. First, the preparation of Ni-Si-Zr alloy is via arc-melting technique. Forty-two as-cast sample analyses provide the primary solidifying phase encompassing the Ni-Si-Zr composition domain. Heat-treatment of fifteen samples at 1073 K refines the isothermal section, emphasizing the Zr-rich corner. Ni-Si-Zr alloy’s temperature recording using pyrometer in the arc-melting device while cooling after melting reveals novel Ni-Si-Zr’s invariant reactions. The time versus temperature graph comparison with its as-cast electron micrograph reveals several phase transitions. The notable research output of this research work is the hybrid approach, including the experiments circumventing hurdles at high temperatures and the first-principles method to calculate the intermetallic phase’s formation energy. The hybrid approach in the present work has established a phase diagram and the thermodynamic description over the extensive temperature and composition ranges for a highly complicated ternary system. The presently developed hybrid methodology is also applicable to construct a phase diagram for other complex ternary systems up to ≈ 3700 K.

Influence of silicon morphology on direct current plasma electrolytic oxidation process in AlSi10Mg alloy produced with laser powder bed fusion

In this work, plasma electrolytic oxidation (PEO) process was applied on AlSi10Mg samples, produced with laser powder bed fusion (L-PBF), in the as printed condition and after different heat treatments, and, for comparison, on as-cast samples of AlSi10Mg. PEO process was performed in direct-current mode using high current densities and short time in a basic silicate electrolyte. For the first time, the effects of silicon morphology in L-PBF AlSi10Mg samples, in as printed condition and after different heat treatments, on the obtained PEO coating were investigated in terms of microstructure and corrosion properties. The microstructure of the substrate was characterized with optical and electron microscopy observations (optical microscopy OM, scanning electron microscopy SEM, and transmission electron microscopy TEM) and with X-ray diffraction (XRD). The analysis showed that heat treatments of annealing and solution treating modified the morphology and distribution of silicon in the samples obtained through L-PBF. The PEO coated samples were characterized with SEM, both on the surface and in the cross-section, and compositional analysis were performed with energy dispersive spectroscopy (EDS) analysis and elemental mapping. The coatings were also analyzed with XRD and the corrosion properties evaluated through electrochemical impedance spectroscopy (EIS) tests. Also microhardness tests were performed on the substrates and on the coatings. The microstructure of the coatings was strongly influenced by the silicon distribution. In particular, a non-uniform distribution of silicon and the presence of iron-rich intermetallic (obtained in the as-cast and solution treated samples) induced the formation of more porous and thinner coatings in comparison with the ones obtained in the as printed and annealed samples. The not-uniform silicon distribution produced a not-homogenous distribution of silicon into the coatings. The particular cellular structure of the as printed sample induced the formation of a coating with a higher amorphous fraction, in comparison with the ones produced on the other samples. The higher thickness and lower porosity of the coatings obtained on the annealed and as printed samples resulted in an increase of the corrosion resistance.