Coarse Grain Research Articles

Electrochemical corrosion behavior of Nbx(MoTaW)(1−x) (x = 0.25, 0.4, 0.55, and 0.7) refractory multicomponent alloys

The current study investigates the effect of increasing Nb concentration in Nbx(MoTaW)(1−x) refractory multicomponent alloys (RMCAs) on corrosion behavior in 3.5 wt% NaCl. The as-processed alloys showed a single-phase BCC crystal structure. With increasing Nb content, the open circuit potential values increase towards the positive direction, which indicates the formation of a stable oxide layer. In addition, polarization curves of RMCAs showed the passive layer formation, while pitting was not observed upto 2 V. The corrosion rate decreased as the Nb content increased, which may be attributed to the presence of coarse grains in high Nb-content RMCAs. Finally, the corrosion resistance of Nb0.7(MoTaW)0.3 is high compared to other alloys. Following the corrosion test, the presence of pits was not observed, indicating uniform corrosion, which is also corroborated by polarization data. X-ray photoelectron spectroscopy detected the presence of Nb2O5, Ta2O5, WO3 and MoO3 in the oxide layer, showing the active participation of all alloying elements in the corrosion process.

FtMYB163 Gene Encodes SG7 R2R3-MYB Transcription Factor from Tartary Buckwheat (Fagopyrum tataricum Gaertn.) to Promote Flavonol Accumulation in Transgenic Arabidopsis thaliana.

Tartary buckwheat (Fagopyrum tataricum Gaertn.) is a coarse grain crop rich in flavonoids that are beneficial to human health because they function as anti-inflammatories and provide protection against cardiovascular disease and diabetes. Flavonoid biosynthesis is a complex process, and relatively little is known about the regulatory pathways involved in Tartary buckwheat. Here, we cloned and characterized the FtMYB163 gene from Tartary buckwheat, which encodes a member of the R2R3-MYB transcription factor family. Amino acid sequence and phylogenetic analysis indicate that FtMYB163 is a member of subgroup 7 (SG7) and closely related to FeMYBF1, which regulates flavonol synthesis in common buckwheat (F. esculentum). We demonstrated that FtMYB163 localizes to the nucleus and has transcriptional activity. Expression levels of FtMYB163 in the roots, stems, leaves, flowers, and seeds of F. tataricum were positively correlated with the total flavonoid contents of these tissues. Overexpression of FtMYB163 in transgenic Arabidopsis enhanced the expression of several genes involved in early flavonoid biosynthesis (AtCHS, AtCHI, AtF3H, and AtFLS) and significantly increased the accumulation of several flavonoids, including naringenin chalcone, naringenin-7-O-glucoside, eriodictyol, and eight flavonol compounds. Our findings demonstrate that FtMYB163 positively regulates flavonol biosynthesis by changing the expression of several key genes in flavonoid biosynthetic pathways.

Elucidating the effects of metal transfer modes and investigating the material properties in wire-arc additive manufacturing (WAAM)

AbstractStudies have shown the influence of WAAM process parameters on mechanical properties, bead formation, dimensional accuracy, and microstructure. However, metal transfer modes and their interactions with input variables have not been investigated thoroughly. Therefore, short/spray, pulse and double pulse modes were investigated in this study at different current levels. Bead-on-plate trials were conducted by depositing ER70S-6 wire to investigate bead morphology, dilution, microstructure, and hardness. The study was supported by a detailed statistical approach, including analysis of variance (ANOVA) and regression analysis. Similarly, the combined effects of hatch distance and current were studied on bead formation in multi-layer deposits. Moreover, a thin wall and a cubic structure were deposited to realize the WAAM capability for larger depositions. The microstructures of thin wall and cubic structure were analyzed using optical microscopy (OM) and scanning electron microscopy (SEM). The study concludes that metal transfer modes at various currents significantly influence bead geometry, microstructure and hardness. The microstructure of bead-on-plate trials show fine lamellar structure at low current in all modes. Higher current results in coarse grains with a polygonal and columnar morphology. The hardness shows a decreasing trend as the current increases. The combined effects of current and hatch distance alter bead morphology; however, an optimized combination yields smoother surfaces. The microstructure of thin wall showed a slight anisotropy along the building direction. The presence of small pores was witnessed from OM and SEM images. Similarly, the cubic structure showed a more homogeneous microstructure with much lower porosity. The hardness profile of the thin wall exhibited small fluctuations along the building direction, while that of the cubic structure was more uniform.

Investigation of the impact of process parameters and thermal treatments on mechanical properties and microstructure of ScanCromAl ® manufactured via powder bed fusion laser beam process

This study explores the processability window of a newly developed aluminium alloy for laser beam powder bed fusion (PBF-LB/M). The impact of the volumetric energy density on the melt pool shape, microstructure, and mechanical properties of manufactured parts are evaluated. Additionally, thermal treatments are optimized to tailor precipitation hardening mechanisms. The results demonstrate the promising potential of this material, exhibiting high relative density (>99.90%) and competitive mechanical properties for the thermally treated samples (UTS ranging from 486 MPa to 514 MPa with elongation of 11–30%). EBSD analysis reveals a characteristic bimodal microstructure of fine equiaxed grains at grain boundaries and elongated coarse grains aligned along the melt pool direction. This work provides valuable insights for tailoring the processing parameters and optimizing the performance of this novel material for diverse applications.

Microstructural evolution and hydrogen embrittlement in simulated reheated coarse-grained heat-affected zone of a high-strength naval steel

The influence of simulated reheated coarse-grained heat-affected zones (CGHAZ) on the microstructural evolution and hydrogen embrittlement in high-strength naval steel was investigated by scanning electron microscopy, microhardness testing, electron backscatter diffraction, slow strain rate tensile test and fracture morphology analysis. Twinned martensites were observed in both the intercritical and super-critically reheated CGHAZ, with a widely spaced region in the former. Intercritical reheated coarse-grained HAZ (ICCGHAZ) was the weakest zone of reheated CGHAZ when the peak temperature was 660 °C, exhibiting the intergranular cracking feature. Twinned martensite and coarsening grain size were therefore concluded to be the main reasons for high hydrogen embrittlement susceptibility in the reheated CGHAZ.

Effect of Laser Parameters on Fracture Properties of Laser-Repaired Cracks with Micro/NanoMaterial Addition: Multiscale Analysis.

In laser crack repair processes, laser parameters have significant influence on repair quality. Improper combination of laser process parameters may result in defects-such as porosity, ablation, and coarse grain size-in remelted zones. A trans-scale computational model is established by combining crystal plasticity finite elements and variable-node finite elements. The influence of microstructure characteristics such as grain size and porosity of the repair layer on the cumulative plastic slip (CPS) on the dominant slip system at the meso-scale and the J-integral at the macro-scale is studied to explore the effect of laser process parameters on repair quality. The results show that when the laser power is 1800 W and the heating time is 0.5 s, the grain size and porosity of the repaired specimen are the smallest. The J-integral of the repaired specimen is more than 8% smaller than that of the unrepaired specimen and about 3% smaller than that of the repaired specimen, with a laser power of 2000 W and a heating time of 1 s. Pores increase the CPS of the crystal around the pores, especially when a pore have sharp corners. Selecting appropriate laser process parameters can not only refine grain size but also reduce the volume fraction of pores and thus reduce the J-integral and eventually improve repair quality of repaired specimens. The study investigates the relationship of process parameter-microstructure-repair quality in the laser repair process and provides a method for studying the mechanical behavior of materials at macro and micro scales.

Effect of Ti, Mn and Mo on the microstructure and properties of CoCrFeNi high entropy alloy coatings prepared by laser cladding

CoCrFeNi-based High Entropy Alloys (HEAs) coatings, with additions of Ti, Mn, and Mo, were synthesized using laser cladding (LC). The pure CoCrFeNi HEA had a uniform FCC structure, exhibiting the lowest hardness and wear resistance but good corrosion resistance. The Ti-added HEA had an FCC+Laves+η phase structure, showing increased hardness and wear resistance due to abrasive and mild surface fatigue wear, though with the poorest corrosion resistance. The Mn-added HEA maintained a single FCC structure with coarser grain boundaries, exhibiting lower hardness and reduced wear resistance due to adhesive, abrasive wear, and minor surface fatigue wear, but with the best corrosion resistance.The Mo-added HEA developed a eutectic structure of FCC and σ phases, achieving the highest hardness and wear resistance due to oxidative wear, but showed moderately decreased corrosion resistance. The varying microstructures significantly impacted the coatings' mechanical properties and corrosion behavior, highlighting the critical role of alloying elements in customizing LCed-HEA coatings for specific applications.

Enhancing fatigue crack propagation resistance of heterostructured Al composites and multistage crack mechanisms

High tensile strength and low fatigue crack propagation (FCP) rate are hard to achieve simultaneously in aluminium (Al) based materials, which has been a long-lasting topic. It is because the traditional strengthening mechanisms may lead to the increase in FCP rate. In this work, we developed dual-level heterostructures by incorporating the in-situ synthesized TiB2 particles into Al matrix, to create particle-lean zones (PLZs) and particle-rich zones (PRZs) by extrusion. Fine grains were introduced by particle-associated local recrystallization in PRZs. By means of particle and grain size distribution, a heterostructured Al composite featuring with the coarse grains in PLZs and fine grains in PRZs was fabricated. It was found that simultaneous enhancement of both the strength and FCP resistance of Al composite was achieved through the development of heterostructures. During FCP, the PRZs can retard the growth of slip bands and increase crack deflection frequency while the PLZs increase the crack deflection distance and plastic deformation capability at crack tip. The fracture behavior of composite during FCP depended on grain characteristics, particles and stress intensity range. The detailed cracking behavior for typical <100>Al and <111>Al grains in different FCP stages was identified. The associated models were developed for different FCP behaviors. Particularly, the quantitative relationship between Pairs parameters and microstructure features was established, which was critical to understand fatigue properties of Al composite reinforced by small particles. These findings can provide a strategy to design metal materials with an excellent combination of both static and dynamic mechanical properties.

Cryogenic tribological behavior of coarse, ultrafine grained and heterogeneous Fe-18Cr-8Ni austenitic stainless steel

Commonly used austenitic stainless steels (ASSs) have some limitation in sliding wear conditions due to their relatively low yield strength and hardness. To improve the wear resistance, three kinds of microstructure (coarse grain (CG), heterogeneous structure (HS), and ultrafine grain (UFG)) are prepared, to investigate the grain size on the dry sliding tribological behavior, as well as wear mechanisms of Fe-18Cr-8Ni ASSs at room temperature (RT) and cryogenic temperature (−120 °C). The results indicate that at RT the UFG specimen exhibits the lowest wear rate during the wear tests, where the wear mechanisms are mainly oxidation wear and abrasive wear. While, when tested at −120 °C, the CG specimen exhibits the best wear resistance compared with that of the other two specimens due to its superior plastic deformation ability and strain hardening ability. Moreover, the HS specimen exhibits the lowest coefficient of friction (CoF), which is due to the abrasive particles generated on the contact surface provide a certain level of friction reduction, while the wear rate increases as these particles serve as third-party abrasives, which further removing material.

Effect of laser parameters on microstructure and mechanical properties of Al–Ni–Sc–Zr alloys fabricated by laser powder bed fusion

The processability, microstructure and mechanical properties of a near eutectic AlNiScZr alloy fabricated by laser powder bed fusion (LPBF) are investigated. The optimal processing windows for the LPBF alloy are determined. The results indicate that laser power exerts a predominant influence on the relative density of the as-built alloy. Elevated laser power can lead to increased relative density. Laser scanning speed exerts a significant impact on the microstructure and mechanical properties of the as-built alloys. An increase in the laser scanning speed can facilitate the growth of coarse columnar grains in the coarse grain region and suppress the formation of ultrafine equiaxed grain bands. Furthermore, the increase in the laser scanning speed can result in a reduction in the size of the cells, which in turn leads to an enhancement in the strength of the alloys. This study examines the evolution of the microstructure and mechanical properties of the as-built alloy as a function of laser scanning speed. By elucidating the relationship between laser parameters, microstructure and mechanical properties, the objective is to provide fundamental guidance for tuning the solidification structures and mechanical properties of LPBF AlNiScZr alloys by selecting appropriate laser parameters.

A high magnetic energy product obtained in hot-deformed Nd-Fe-B magnet by chemical plating Fe-Co bilayer films

This study investigates a novel method, chemical plating, with the goal of integrating nano-sized ferromagnetic materials into hot-deformed Nd-Fe-B magnets, potentially enhancing their magnetic properties. Coating Fe-Co double layers on Nd-Fe-B magnetic powder resulted in a significant improvement in the remanence over 10 %, increasing from 1.37 to 1.45 T, as well as an increase in the maximum magnetic energy product from 45.95 to 52.02 MGOe in hot-deformed Nd-Fe-B magnets. Microstructure observations revealed that the coarse non-oriented grains at the interface of powder ribbons were suppressed and the texture of grain alignment in the interior of powder ribbons was enhanced after the coating of Fe-Co. Additionally, there was a noticeable increase in the concentrations of ferromagnetic elements in intergranular phases. The reduced coarse grain regions, the enhanced grain alignment and the increased ferromagnetic intergranular phases are considered to be the main reasons for the enhancement of remanence and maximum magnetic energy product in hot-deformed magnets.

Enhancing the mechanical properties and corrosion resistance of biomedical Ti15Mo alloy with ultra-finer {332} twins via cyclic deformation

Mechanical properties, passivation behaviors and corrosion resistance of biomedical Ti15Mo alloy with ultra-finer twins were investigated. Cyclic deformation was conducted to activating more {332} twin variants via periodic changes of tension and compression. Microstructural refinement via numerous twins with the stable boundaries is different from other mechanisms, resulting in a higher hardness and maintaining the low elastic modulus after deformation and annealing. The results of electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy tests, revealed that twin boundaries are beneficial to enhancing passivation behaviors via forming a thicker oxide film in PBS solution. The alloy with ultra-finer {332} twins exhibit a better corrosion resistance due to a lower passivation current. The expected biomedical performance was obtained in the alloy after ±3 % amplitude cyclic deformation and 730 °C/7 min annealing, in contrast to the initial alloy with coarse grains, increasing 8.8 % of the hardness, decreasing 46 % of the corrosion current and maintaining the low elastic modulus.

A Small Molecule Impedes the Aβ1-42 Tetramer Neurotoxicity by Preserving Membrane Integrity: Microsecond Multiscale Simulations.

Amyloid-β (Aβ1-42) peptides aggregated into plaques deposited in the brain are the main hallmark of Alzheimer's disease (AD), a social and economic burden worldwide. In this context, insoluble Aβ1-42 fibrils are the main components of plaques. The recent trials that used approved AD drugs show that they can remove the fibrils from AD patients' brains, but they did not halt the course of the disease. Mounting evidence envisages that the soluble Aβ1-42 oligomers' interactions with the neuronal membrane trigger higher cell death than Aβ1-42 fibril interactions. Developing a compound that can alleviate the oligomer's toxicity is one of the most demanding tasks for curing the disease. We performed two molecular dynamics (MD) simulations in an explicit solvent model. In the first case, 55-μs of multiscale all-atom (AA)/coarse-grained (CG) MD simulations were carried out to decipher the impact of a previously described small anti-Aβ molecule, termed M30 (2-octahydroisoquinolin-2(1H)-ylethanamine), on an Aβ1-42 tetramer structure in close contact with a DMPC bilayer. In the second case, 15-μs AA/CG MD simulations were performed to rationalize the dynamics between Aβ1-42 and Aβ1-42-M30 tetramer complexes embedded in DMPC. On the membrane bilayer, we found that the Aβ1-42 tetramer penetrates the bilayer surface due to unrestricted conformational flexibility and many contacts with the membrane phosphate groups. In contrast, no Aβ1-42-M30 tetramer penetration was observed during the entire course of the simulation. In the case of the membrane-embedded Aβ1-42 tetramer, the integrity of the bottom bilayer leaflet was severely affected by the interactions between the negatively charged phosphate groups and the positively charged residues of the Aβ1-42 tetramer, resulting in a deep tetramer penetration into the bilayer hydrophobic region. These contacts were not observed in the case of the membrane-embedded Aβ1-42-M30 tetramer. It was noted that M30 molecules bind to Aβ1-42 tetramer through hydrogen bonds, resulting in a conformational stable Aβ1-42-M30 complex. The associated complex has reduced conformational changes and an enhanced rigidity that prevents the tetramer dissociation by interfering with the tetramer-membrane contacts. Our findings suggest that the M30 molecules could bind to Aβ1-42 tetramer resulting in a rigid structure, and that such complexes do not significantly perturb the membrane bilayer organization. These observations support the in vitro and in vivo experimental evidence that the M30 molecules prevent synaptotocity, improving AD-affected mice memory.

Microstructure and corrosion characteristics of AA5083 alloy weld beads produced by GTAW and SpinArc-GMAW

In this study, bead-on-plate welding was performed on a sheet of AA5083 alloy using two distinct welding techniques: gas tungsten arc welding (GTAW) and SpinArc-gas metal arc welding (SA-GMAW). This study compares the microstructural, mechanical, and corrosion characteristics of processed weld beads. The microstructural features of the weld beads were characterized using optical microscope (OM), scanning electron microscope (SEM) and high-resolution transmission electron microscope (HR-TEM). The corrosion characteristics of weld beads were determined by potentiodynamic polarization method, and the corrosion morphology of the specimens were observed under SEM. In addition, a microhardness study was performed on the weld beads across the base metal (BM), heat affected zone (HAZ), and fusion zone (FZ). The findings indicate that the weld bead produced by GTAW exhibited superior corrosion resistance compared to the weld bead processed by SA-GMAW. The presence of porosities in the latter facilitated the corrosive medium to penetrate and break the passive layer easily that developed deeper corrosive pits. The presence of Fe and Mn rich intermetallics in FZ of GTAW processed weld bead assisted in better rate of corrosion observed at 0.1259 mm/yr. The hardness observed in the FZ of the SA-GMAW bead was found to be lower compared to the GTAW weld bead due to the presence of porosities and coarser grains.

Optimizing heterostructure parameters towards enhanced toughening in micro/nano-reinforced bimodal-grained Al alloy composites

We manipulated soft coarse-grained (CG) domains to design optimized and toughened B4Cp/6061Al composites, featuring bimodal domains with in-situ MgO nanoparticles (n-MgO) and ex-situ carbon nanotubes (CNTs). Manipulating CG fractions influenced heterostructure parameters such as CG band width and domain distribution. A systematic optimization strategy integrating intrinsic/extrinsic toughening and strengthening mechanisms identified optimal conditions for maximizing strength-ductility-toughness. The optimal 20:80 CG-to-ultrafine-grain (UFG) weight ratio offered an ultimate strength of 550 MPa and ∼7 % elongation. Intrinsic toughening mechanisms enhanced UFG domain dislocation storage capacity. Multiscale analysis of crack behavior revealed pronounced crack-blunting in well-dispersed CG domains. Extrinsic toughening mechanisms included nanobridge formation, crack-deflection, micro-crack proliferation, and crack-branching. Micromechanical behavior was examined using the strain gradient model. Designing strong and ductile micro/nano-reinforced bimodal grained composites requires selecting a smaller amount of CG domains, a CG band width larger than double the interface affected zone (IAZ), and larger grain sizes in the CG domains.

The combined effects of carbides and martensite blocks heterogeneity on the fatigue life scatter in bearing steel

With the mitigation of inclusion-related harm through purifying methods, the fatigue life scatter of bearing steels is now predominantly governed by microstructural heterogeneity. This work employs an integrated experimental-numerical approach to elucidate the microstructure-related localized plastic strain in 52100 bearing steel under cyclic loading. We observed significant localized plastic strain in the coarse grains adjacent to aggregated carbides after unloading, which may act as a precursor to fatigue cracks and contribute to fatigue life scatter. This strain arises from two primary factors: stress concentration due to aggregated carbides and the relatively lower strength of coarse matrix grains, which is usually overlooked. Enhancing the homogeneity of both carbide distribution and matrix grain size will be a strategy to reduce the fatigue life scatter of bearing steels.

Enhanced corrosion resistance of harmonic structured β-type Ti-25Nb-25Zr alloy in aerated Fusayama-Meyer’s simulated saliva solution

In this study, the microstructure of the β-type Ti-25Nb-25Zr alloy is modified to a bimodal harmonic design, exhibiting fine and coarse grains of ∼3 μm and ∼70 μm, respectively. The high-angle grain boundary density of the harmonic Ti-25Nb-25Zr alloy increases nearly fourfold over its coarse-grained counterpart. Both the harmonic and course-grained Ti-25Nb-25Zr alloys show excellent passivation and corrosion resistance when studied electrochemically in Fusayama-Meyer’s simulated saliva solution. The harmonic structure in the Ti-25Nb-25Zr further improves corrosion resistance, almost six times the coarse-grained counterpart. The improved corrosion resistance is attributed to the excessive high-angle grain boundary, which binds the corrosion product to the substrate, restricting further corrosion.

Microstructural evolution and strength enhancement in laser powder bed fusion Al-Mg-Yb-Zr alloys

Al-Mg alloys fabricated by laser powder bed fusion (L-PBF) usually suffer from poor processability and strength response. In this work, the effect of Yb and Zr in Al-Mg alloys was studied using Al-3Mg-0.7Zr and Al-3Mg-0.5Yb-0.7Zr alloys fabricated by L-PBF. The size of average grain along the building direction was measured to be 3.6 μm, of which 94.2 % consisted of equiaxed grains. The formation of Al3(Yb,Zr) phase in the L-PBF was revealed through single-track and multi-track melt pools and the formation of Al3Zr, Al/Al3Yb eutectics, in couple with the L12-Al3(Yb,Zr) phase were found to be responsible for the high-volume fraction of refined equiaxed grains. After aging at 375 ℃ for 14 h, a high-volume fraction L12-Al3(Yb,Zr) (4.5 nm) was formed within the relatively coarse grains (5.8 μm), which showed strong thermal stability and precipitation strengthening. As such, the as-aged Al-3Mg-0.5Yb-0.7Zr alloy can deliver a good combination of strength-ductility, in which ultimate tensile strength (UTS) and elongation (El) are 401 MPa and 15.1 %, respectively.

Anisotropic microstructure and tensile property of laser powder bed fusion fabricated Al–Mn–Mg–Sc–Zr alloy built at different layer thickness

Laser powder bed fusion (LPBF) fabricated Al–Mn–Mg-Sc-Zr alloy generally possesses a bi-modal microstructure of columnar grains and equiaxed grains. Such an anisotropic microstructure would introduce varied tensile performance in different orientations. To date, few study on the microstructure and tensile property anisotropy have been reported for LPBF fabricated Al–Mn–Mg-Sc-Zr alloys built at different layer thicknesses, which limits the exploration in mechanical property optimization. In this work, the microstructure anisotropy and room-temperature tensile properties of LPBF produced and peak-aged Al–Mn–Mg-Sc-Zr alloys built at 30 and 60 μm layer thicknesses were systematically investigated by scanning electron microscope, transmission electron microscope, and tensile testing. A higher layer thickness of 60 μm resulted in coarser grains with the precipitates size remained similarly compared to the 30 μm specimens. This led to a reduced yield strength in 60 μm specimens (492–509 MPa) comparing to those in 30 μm specimens at 502 MPa–510 MPa. In addition, the existence of columnar grains within melt pools contributed to a larger effective slip length in the vertical direction than that in the horizontal orientation. Such difference in effective slip length in the loading direction contributed to a lower strength in vertical orientations. For ductility, the slightly higher defect level in 60 μm specimens (0.58%) resulted in reduced elongations of 3%–6% compared to those of 30 μm specimens (0.10%). The ductility anisotropy was attributed to the preferential distribution of gas pores and keyhole defects at melt pool boundaries.

Enhancing microstructure and mechanical properties of laser directed energy deposited AlSi10Mg alloy by friction stir processing

The low strength-plastic properties of AlSi10Mg alloy prepared by laser directed energy deposition (LDED) have limited its application in aerospace and related fields, prompting researchers to explore friction stir processing (FSP) as a viable post-treatment solution. This study investigated the effects of FSP on the microstructure and mechanical properties of AlSi10Mg alloy formed by LDED, revealing that FSP effectively eliminated pores and refined grains, transforming the coarse and uneven grains in base material (BM) into fine and uniform equiaxed grains. Consequently, the thermal mechanical affected zone presented a microstructure gradient due to the uneven distribution of material flow and frictional heat. Additionally, the yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of LDEDed specimens were determined to 91.98 MPa, 158.57 MPa, and 4.29 %, respectively. YS and UTS of LDED-FSPed specimens were increased about 20 % and 30 %, and EL was greatly improved approximately 2–3 times compared with LDEDed specimens. Consequently, the grain refinement and porosity elimination caused by FSP improve the mechanical properties and microstructure evolution of LDED-FSPed specimens.