Coarse Grain Research Articles

Systematic Approach to Parametrization of Disaccharides for the Martini 3 Coarse-Grained Force Field.

Sugars are ubiquitous in biology; they occur in all kingdoms of life. Despite their prevalence, they have often been somewhat neglected in studies of structure-dynamics-function relationships of macromolecules to which they are attached, with the exception of nucleic acids. This is largely due to the inherent difficulties of not only studying the conformational dynamics of sugars using experimental methods but indeed also resolving their static structures. Molecular dynamics (MD) simulations offer a route to the prediction of conformational ensembles and the time-dependent behavior of sugars and glycosylated macromolecules. However, at the all-atom level of detail, MD simulations are often too computationally demanding to allow a systematic investigation of molecular interactions in systems of interest. To overcome this, large scale simulations of complex biological systems have profited from advances in coarse-grained (CG) simulations. Perhaps the most widely used CG force field for biomolecular simulations is Martini. Here, we present a parameter set for glucose- and mannose-based disaccharides for Martini 3. The generation of the CG parameters from atomistic trajectories is automated as fully as possible, and where not possible, we provide details of the protocol used for manual intervention.

CG modeling of nucleosome arrays reveals the salt-dependent chromatin fiber conformational variability.

Eukaryotic DNA is packaged in the cell nucleus into chromatin, composed of arrays of DNA-histone protein octamer complexes, the nucleosomes. Over the past decade, it has become clear that chromatin structure in vivo is not a hierarchy of well-organized folded nucleosome fibers but displays considerable conformational variability and heterogeneity. In vitro and in vivo studies, as well as computational modeling, have revealed that attractive nucleosome-nucleosome interaction with an essential role of nucleosome stacking defines chromatin compaction. The internal structure of compacted nucleosome arrays is regulated by the flexible and dynamic histone N-terminal tails. Since DNA is a highly negatively charged polyelectrolyte, electrostatic forces make a decisive contribution to chromatin formation and require the histones, particularly histone tails, to carry a significant positive charge. This also results in an essential role of mobile cations of the cytoplasm (K+, Na+, Mg2+) in regulating electrostatic interactions. Building on a previously successfully established bottom-up coarse-grained (CG) nucleosome model, we have developed a CG nucleosome array (chromatin fiber) model with the explicit presence of mobile ions and studied its conformational variability as a function of Na+ and Mg2+ ion concentration. With progressively elevated ion concentrations, we identified four main conformational states of nucleosome arrays characterized as extended, flexible, nucleosome-clutched, and globular fibers.

Tracking Cholesterol Flip-Flop in Mammalian Plasma Membrane through Coarse-Grained Molecular Dynamics Simulations.

Plasma membrane (PM) simulations at longer length and time scales at nearly atomistic resolution can provide invaluable insights into cell signaling, apoptosis, lipid trafficking, and lipid raft formation. We propose a coarse-grained (CG) model of a mammalian PM considering major lipid head groups distributed asymmetrically across the membrane bilayer and validate the model against bilayer structural properties from atomistic simulation. Using the proposed CG model, we identify a recurring pattern in the passive collective cholesterol transbilayer motion and study the individual cholesterol flip-flop events and associated pathways along with lateral ordering in the bilayer during a flip-flop event. We identify two discrete cholesterol flip-flop pathways: (i) a systematic rototranslational pathway and (ii) intraleaflet inversion followed by interleaflet translation (or reverse). We observe a periodic cholesterol enrichment in the exoplasmic leaflet of the PM bilayer and examine the underlying cholesterol-lipid affinities. We observe closer association between cholesterol and palmitoylsphingomyelin (PSM) lipid, relative to other lipids, and conclude that the cholesterol enrichment in the exoplasmic leaflet can be attributed to higher PSM content in that leaflet, together leading to formation of short-lived PSM-cholesterol-rich domains.

TIG Welding of EN AW-6082 Al Alloy: A Comparative Analysis of Filler Rods on Microstructural and Mechanical Performance

This study investigates the impact of different filler wires (ER5356, ER4043, and ER4047) on the microstructural and mechanical properties of EN AW-6082 Al alloy joints produced by tungsten inert gas (TIG) welding. Butt-welded samples with a single V-groove joint configuration were prepared using optimized welding parameters. The welded samples were subjected to visual inspection, microstructural analysis, hardness testing, tensile testing, and impact toughness evaluation. The results showed that all the welds were free of visible defects. Microstructural examination revealed that the ER5356 filler produced the finest grain structure of 18.03 ± 3 μm, while ER4047 resulted in the coarsest grains of 36.07 ± 5 μm. Correspondingly, the joints made with ER5356 exhibited the highest tensile stress of 278 ± 6 MPa, yield stress of 219 ± 5.4 MPa, hardness values of 72.7 ± 5 HV, and welding efficiency of 86.07%, whereas those made with ER4047 produced the lowest values. The hardness in the weld region was lower than that in the parent metal and heat-affected zone for all samples. However, ER4047 welds demonstrated superior impact toughness and strain-hardening capacity. The findings underscore the importance of filler metal selection in tailoring mechanical properties for high-performance applications.

A Neural-Network-Based Mapping and Optimization Framework for High-Precision Coarse-Grained Simulation.

The accuracy and efficiency of a coarse-grained (CG) force field are pivotal for high-precision molecular simulations of large systems with complex molecules. We present an automated mapping and optimization framework for molecular simulation (AMOFMS), which is designed to streamline and improve the force field optimization process. It features a neural-network-based mapping function, DSGPM-TP (deep supervised graph partitioning model with type prediction). This model can accurately and efficiently convert atomistic structures to CG mappings, reducing the need for manual intervention. By integrating bottom-up and top-down methodologies, AMOFMS allows users to freely combine these approaches or use them independently as optimization targets. Moreover, users can select and combine different optimizers to meet their specific mission. With its parallel optimizer, AMOFMS significantly accelerates the optimization process, reducing the time required to achieve optimal results. Successful applications of AMOFMS include parameter optimizations for systems such as POPC and PEO, demonstrating its robustness and effectiveness. Overall, AMOFMS provides a general and flexible framework for the automated development of high-precision CG force fields.

Mesoscopic Modeling of Bio-Compatible PLGA Polymers with Coarse-Grained Molecular Dynamics Simulations.

A challenging topic in materials engineering is the development of numerical models that can accurately predict material properties with atomistic accuracy, matching the scale and level of detail achieved by experiments. In this regard, coarse-grained (CG) molecular dynamics (MD) simulations are a popular method for achieving this goal. Despite the efforts of the scientific community, a reliable CG model with quasi-atomistic accuracy has not yet been fully achieved for the design and prototyping of materials, especially polymers. In this paper, we describe a CG model for polymers, focusing on the biocompatible poly(lactic-co-glycolic acid) (PLGA), based on a general parametrization strategy with a potentially broader field of applications. In this model, polymers are represented with finite-size ellipsoids, short-range interactions are accounted for with the generalized Gay-Berne potential, while electrostatic and long-range interactions are accounted for with point charges within the ellipsoids. The model was validated against its atomistic counterpart, obtained through a back-mapping process, by comparing physical properties such as glass transition temperature, thermal conductivity, and elastic moduli. We observed quantitative agreement between the atomistic and CG representations, thus opening up the possibility of adopting the proposed model to expand the domain size of typical MD simulations to dimensions comparable to those of experimental setups.

Elasticity of Swollen and Folded Polyacrylamide Hydrogel Using the MARTINI Coarse-Grained Model.

One of the key advantages of using a hydrogel is its superb control over elasticity obtained through variations of constituent polymer and water. The underlying molecular nature of a hydrogel is a fundamental origin of hydrogel mechanics. In this article, we report a Polyacrylamide (PAAm)-based hydrogel model using the MARTINI coarse-grained (CG) force field. The MARTINI hydrogel is molecularly developed through Iterative Boltzmann inversion (IBI) using all-atom molecular dynamics (AAMD), and its quality is evaluated through the experimental realization of the target hydrogel. The developed model offers a mechanically high-fidelity CG hydrogel that can access large-scale water-containing hydrogel behavior, which is difficult to explore through AAMD in practical time. With the modeled hydrogel, we reveal that the polymer conformation modulates the elasticity of the hydrogel from a folded state to a swollen state, confirmed by the Panyukov model. The results provide a robust bridge for linking the polymer conformations and alignment to their bulk deformation, enabling the multifaceted and material-specific predictions required for hydrogel applications.

Effect of longitudinal direct current magnetic field and heat treatment composite process on microstructure and mechanical properties of 2319 aluminum alloy WAAM

Wire arc additive manufacturing (WAAM) had been proven to be viable for producing large metal components. However, its optimal performance had been limited by defects such as porosity, elemental segregation, and coarse grains. This study had introduced a composite process of applying a direct current magnetic field along with heat treatment to improve the microstructure and mechanical properties of the specimens, while also comparing changes under four different conditions. The results had indicated that applying a direct current magnetic field had expanded the arc and improved the macroscopic morphology. With a direct current of 2A, the specimen had the fewest macropores, making it the optimal parameter. After applying the magnetic field alone, porosity had significantly decreased, with a reduction of 0.43% compared to the blank specimen, and the average pore volume had decreased by 10.45mm³ compared to the blank specimen. After the composite application of the magnetic field and heat treatment, the proportion of recrystallization had increased, Cu element segregation had been notably improved, maximum texture strength had decreased, the proportion of high-angle grain boundaries had increased, and porosity improved by the magnetic field had increased. In terms of mechanical properties, the average microhardness had reached 206.2 HV, an increase of 104.36% compared to the blank specimen. The longitudinal average tensile strength had reached 387.9MPa, a 63.3% improvement over the blank specimen. Anisotropy had decreased, while elongation had been reduced.

Study on size effect affected multi-stage micro deep drawing forming directly using pure titanium foils

In response to the problems of wrinkling and fracture in the single-stage micro deep drawing of TA1 pure titanium (Ti) foils, a blanking and multi-stage micro deep drawing (MMDD) forming system has been developed to facilitate the production of micro parts directly from sheet metal. In this study, the influence of size effect on the deformation behavior of TA1 pure Ti foils (50 μm) and the surface quality of the formed cups during MMDD was investigated. It is found that MMDD includes blank bending and the ironing effect during the continuous drawing stages. The deformation forces generated in the second and third stages exceed those resulting in the first stage, and the size effect appeared during the first stage. However, the uncertainty of the ironing effect leads to the attenuation of the size effect in the continuous stages. Moreover, {101̅0} and {112̅0} textures, are identified in the planar direction of the as-received material and contribute to wrinkling and earing, damaging the quality of parts. Subsequently, annealing at 600 °C for 60minutes results in a weakening of the {101̅0} and {112̅0} textures, with the emergence of the {0001} texture. This transformation improves the anisotropy of pure Ti and the quality of parts. But, annealing at 650 °C and 700 °C, the non-uniform plastic deformation of coarse grains adversely impacts the quality of parts, leading to wrinkling or even fracture. Consequently, the optimal annealing temperature for TA1 pure Ti foil blanks in MMDD is 600 °C.

A cellular automata model for recrystallization annealing of aged GH4169 superalloy and its application

For the forging of GH4169, there are often serious mixed and coarse grains that need to be uniformly refined through a multi-stage annealing process. However, it will need to take a lot of time and cost to explore suitable multi-stage annealing process parameters if we only employ the experimental method. The cellular automata (CA) simulation can reveal the evolution of microstructure during forming and annealing, which can obviously reduce the number of experiments. Therefore, in the study, a CA model to simulate the evolution of grain microstructure, dislocation density and δ phase is established. The results demonstrate that the established CA model can effectively predict the microstructural evolution of GH4169. The correlation coefficient exceeds 0.94. Furthermore, using the CA simulation, an optimized multi-stage annealing parameter of “1000 ℃×3min+1000 ℃-5 min-950 ℃+950 ℃×50min” has been identified, which is also verified by experiments. These findings further verify the accuracy and reliability of the model in simulating microstructural evolution during the annealing process of GH4169 forgings. Eventually, based on the CA simulation, the formation mechanism for the uneven grain growth in the annealed microstructure is revealed. At original deformed grain boundaries, dynamic recrystallization (DRX) grains grow slowly, whereas static recrystallization (SRX) grains at DRX boundaries or δ phase boundaries within original deformed grains grow rapidly.

Stress corrosion behavior and microstructure analysis of Al-Zn-Mg-Cu alloys fabricated by CMT wire arc additive manufacturing with different post-treatments

In this study, Al-Zn-Mg-Cu alloys components were fabricated by cold metal transfer (CMT) wire arc additive manufacturing (WAAM), and the stress corrosion cracking (SCC) behavior of the alloys with different post-treatments was studied by combining in-situ electrochemical impedance spectroscopy (EIS) with slow strain rate tensile. The hot-rolling process was employed to close the internal pores of the WAAM products, following by single-stage aging (T6) to further improve the mechanical properties of the products. The elongation loss and SCC susceptibility index of T6 sample are 38.0% and 43.0%, respectively, which exceed those of the hot-rolled sample at 35.5% and 37.0%. Furthermore, the corrosion fracture of the T6 sample exhibits intensive secondary cracks, indicating an increased SCC susceptibility. The stress corrosion process is classified into four stages based on the trend of the EIS: (Ⅰ) Initial stage of corrosion; (Ⅱ) Corrosion products accumulation stage; (Ⅲ) Corrosion products coverage stage; (Ⅳ) Approaching fracture stage. The hot-rolled samples have reduced SCC susceptibility due to the presence of coarse grain boundary precipitates (GBPs) which can act as the irreversible traps to capture hydrogen. The ultimate tensile strength and elongation of T6 sample reached 568.3 ± 11.5MPa and 9.1 ± 0.7%, respectively. However, the small-sized GBPs and wider precipitates-free zone reduced its SCC resistance. This study found that the hot-rolling process can fully exploit the mechanical property potential of Al-Zn-Mg-Cu alloys and improve their SCC resistance, which is an important guiding significance for the practical application of WAAM technology in Al-Zn-Mg-Cu alloys.

EFFECTIVENESS OF CITRONELLA (Cymbopogon nardus) HAND SANITIZER ESSENTIAL OIL ON THE ABILITY TO INHIBIT Escherichia coli PATHOGENIC BACTERIA

Introduction : Hand sanitizer is a hand cleaner that is used as a substitute for washing hands with soap and water. Washing handsproperly and correctly will eliminate bacteria on the palms of the hands, thereby minimizing a person's exposure to diseases such asdiarrhea. Hand sanitizer with additional essential oils is useful in inhibiting bacteria. Bacteria that cause diarrhea include Escherichia coli. This research aims to determine the effectiveness of lemongrass (Cymbopogon nardus) essential oil hand sanitizeron the ability to inhibit the pathogenic bacteria Escherichia coli. Method: This research was a true experimental research. The method stages in this research included refining citronella essential oil, testing the pH of the hand sanitizer, testing the homogeneity of the hand sanitizer, and testing the inhibitory power of the citronella essential oil hand sanitizer against the pathogenic bacteria of Escherichia coli. Result: The research results showed that hand sanitizer has a pH of 6 for each formulation. The homogeneity testing of the hand sanitizer showed a homogeneous composition and no coarse grains were visible. The diameter testing of the inhibition zone showed that the average results from 4 tests were 7.75 mm in formulation I, 10 mm in formulation II, 10.75 mm in formulation III, 11 mm informulation IV, and 14.75 mm in formulation V. Conclusion: Hand sanitizer formulations 1 (negative control) and2 (3%) have inhibition zone results that are classified as intermediate, which indicates that the preparation is less effective in inhibiting Escherichia coli bacteria. While formulation 3 (6%), 4 ( 9%), and 5 (positive control) had inhibition zone results that were classified as sensitive, indicating that the preparation was effective in inhibiting Escherchia coli bacteria.

Validation of a Coarse-Grained Martini 3 Model for Molecular Oxygen.

Molecular oxygen (O2) is essential for life, and continuous effort has been made to understand its pathways in cellular respiration with all-atom (AA) molecular dynamics (MD) simulations of, e.g., membrane permeation or binding to proteins. To reach larger length scales with models, such as curved membranes in mitochondria or caveolae, coarse-grained (CG) simulations could be used at much lower computational cost than AA simulations. Yet a CG model for O2 is lacking. In this work, a CG model for O2 is therefore carefully selected from the Martini 3 force field based on criteria including size, zero charge, nonpolarity, solubility in nonpolar organic solvents, and partitioning in a phospholipid membrane. This chosen CG model for O2 (TC3 bead) is then further evaluated through the calculation of its diffusion constant in water and hexadecane, its permeability rate across pure phospholipid- and cholesterol-containing membranes, and its binding to the T4 lysozyme L99A protein. Our CG model shows semiquantitative agreement between CG diffusivity and permeation rates with the corresponding AA values and available experimental data. Additionally, it captures the binding to hydrophobic cavities of the protein, aligning well with the AA simulation of the same system. Thus, the results show that our O2 model approximates the behavior observed in the AA simulations. The CG O2 model is compatible with the widely used multifunctional Martini 3 force field for biological simulations, which will allow for the simulation of large biomolecular systems involved in O2's transport in the body.

Enhancing metallurgical and mechanical properties of friction stir lap welding of aluminum alloys by microstructure reconstruction

Friction stir processing (FSP) is successfully employed to alleviate their hook defects of friction stir lap welding (FSLW) of aluminum alloys. The mechanical properties and microstructural characteristics are compared and analyzed between the FSLW&FSP joint fabricated by FSLW and FSP and the FSLW joint. The microstructural analysis shows that the hook defect zone at the advancing side of the FSLW joint is changed into the overlap zone (OZ) of the FSLW&FSP joint due to microstructure reconstruction caused by performing the FSP. The heterogeneous and coarse grains at the hook defect zone of the FSLW joint are transformed into refined and equiaxed grains at the OZ of the FSLW&FSP joint as a result of dynamic recrystallization. The results of tensile tests show that tensile strength and fracture toughness of the FSLW&FSP joint are 85.7% and 220% higher compared to those of the FSLW joint, respectively. The cross sections of broken lap joints reveal that their failure location is shifted from the hook defect at AS of the FSLW joint to the thermo-mechanically affected zone of the FSP zone of FSLW&FSP joint. The combined action of effective sheet thickness increasement, microstructure uniformity, grain refinement, and local stress concentration reduction act as the strengthening mechanism of the lap joint of aluminum alloys.

OPTIMIZING SOIL PARTICLE DISTRIBUTION FOR IMPROVED COMPRESSED EARTH BLOCK PERFORMANCE: A MIXING APPROACH

This study presents a soil mixing approach to enhance particle distribution for compressed earth block (CEB) construction. Significant improvements in soil composition were achieved through detailed analysis of soil characteristics and iterative adjustments. Our method involved optimizing curves for the maximal soil diameter to suit different CEB production needs, ensuring applicability across soil types. Supplementary soil from a beach area rich in coarse grains was key in correcting the initial soil’s grain distribution. A systematic method for determining soil mixture percentages using various sieve diameters ensured consistency. The corrected soil showed an increased dry density of 2032 kg/m3 at 8.25% water content, compared to 1965 kg/m3 for the initial soil, demonstrating the practical benefits of this approach. Future research should explore alternative techniques and real-world applications to promote sustainable construction practices and eco-friendly materials.

Investment casting of Cr–Si alloys with liquidus temperatures up to 1900 °C

AbstractIn previous studies, chromium–silicon-based alloys have shown promising material properties for high-temperature applications. For chromium–silicon alloys to be processed on a large scale, primary shaping processes must be adapted to the requirements of these alloys. In this work, binary chromium–silicon alloys are primarily shaped using an investment casting process. Ceramic shell molds made of hafnium oxide stabilized zirconium oxide are developed to withstand the thermal, mechanical and chemical stresses resulting from pouring melts with liquidus temperatures of up to 1900 °C. The layered construction of the shell molds leads to a sufficient thermal shock stability. Energy-dispersive X-ray spectroscopy shows that chemical interactions between the shell mold and the melt do not occur, nor oxides are formed to a detectable extent. Microstructure investigations reveal that casting binary chromium–silicon alloys lead to a coarse grain structure with grain diameters above 300 µm. Strength-increasing precipitations of the intermetallic phase Cr3Si (A15 phase) can be detected from a silicon content of seven-atom percent in the as-cast state.

Molecular dynamics studies of knotted polymers.

Molecular dynamics calculations have been used to explore the influence of knots on the strength of a polymer strand. In particular, the mechanism of breaking 31, 41, 51, and 52 prime knots has been studied using two very different models to represent the polymer: (1) the generic coarse-grained (CG) bead model of polymer physics and (2) a state-of-the-art machine learned atomistic neural network (NN) potential for polyethylene derived from electronic structure calculations. While there is a broad overall agreement between the results on the influence of the pulling rate on chain rupture based on the CG and atomistic NN models, for the simple 31 and 41 knots, significant differences are found for the more complex 51 and 52 knots. Notably, in the latter case, the NN model more frequently predicts that these knots can break not only at the crossings at the entrance/exit but also at one of the central crossing points. The relative smoothness of the CG potential energy surface also leads to stabilization of tighter knots compared to the more realistic NN model.

An in silico framework to visualize how cancer-associated mutations influence structural plasticity of the chemokine receptor CCR3.

G protein Coupled Receptors (GPCRs) are the largest family of cell surface receptors in humans. Somatic mutations in GPCRs are implicated in cancer progression and metastasis, but mechanisms are poorly understood. Emerging evidence implicates perturbation of intra-receptor activation pathway motifs whereby extracellular signals are transmitted intracellularly. Recently, sufficiently sensitive methodology was described to calculate structural strain as a function of missense mutations in AlphaFold-predicted model structures, which was extensively validated on experimental and predicted structural datasets. When paired with Molecular Dynamics (MD) simulations, these tools provide a facile approach to screen mutations in silico. We applied this framework to calculate the structural and dynamic effects of cancer-associated mutations in the chemokine receptor CCR3, a Class A GPCR involved in cancer and autoimmune disorders. Residue-residue contact scoring refined effective strain results, highlighting significant remodeling of inter- and intra-motif contacts along the highly conserved GPCR activation pathway network. We then integrated AlphaFold-derived predicted Local Distance Difference Test scores with per-residue Root Mean Square Fluctuations and activation pathway Contact Analysis (CONAN) from coarse grain MD simulations to identify statistically significant changes in receptor dynamics upon mutation. Finally, analysis of negative control mutants suggests false positive results in AlphaFold pipelines should be considered but can be mitigated with stricter control of statistical analysis. Our results indicate selected mutants influence structural plasticity of CCR3 related to ligand interaction, activation, and G protein coupling, using a framework that could be applicable to a wide range of biochemically relevant protein targets following further validation.

Computational Characterization of the Structure, Energy, Strengths, and Fracture Resistances of Symmetric Tilt Grain Boundaries in Ice.

Using an interatomic potential that can capture the tetrahedral configuration of water molecules (H2O) in ice without the need to explicitly track the motion of the O and H atoms, coarse-grained (CG) atomistic simulations are performed here to characterize the structures, energy, cohesive strengths, and fracture resistance of the grain boundaries (GBs) in polycrystalline ice resulting from water freezing. Taking the symmetric tilt grain boundaries (STGBs) with a tilting axis of ⟨0001⟩ as an example, several main findings from our simulations are (i) the GB energy, EGB, exhibits a strong dependence on the GB misorientation angle, θ. The classical Read-Shockley model only predicts the EGB - θ relation reasonably well when θ < 20° or θ > 45° but fails when 20° < θ < 45°; (ii) two "valleys" appear in the EGB-θ landscape. One occurs at θ = 22° for Σ14(2̅31̅0) GB, and the other is at θ = 32° for Σ26(3̅41̅0) GB. These two GBs might be the most common in polycrystalline ice; (iii) all the STGB structures under consideration here are found to be a collection of edge dislocations with a Burgers vector of b = 1/3⟨112̅0⟩. The core structure of this edge dislocation is composed of a pentagon and a heptagon atomic ring. The separation and orientation of the structure units (SUs) at the GB exhibit a strong dependence on θ; (iv) the length of an atomic bond within the SUs, rather than EGB and θ which are often used in the literature, is identified as one controlling parameter that dictates the intrinsic GB cohesive strength; (v) characterization of the fracture resistance of the GB containing an initial crack is beyond the reach of nanoscale atomistic simulations but is feasible in concurrent atomistic-continuum (CAC) simulations that can simultaneously retain the atomic GB structure together with the long-range stress field within one model. The above findings provide researchers with a stepping stone to understand the complex microstructure of polycrystalline ice and its response to external forces from the bottom up. Such knowledge may be consolidated into constitutive rules and then transferred into the higher length scale models, such as cohesive zone finite element models (CZFEMs), for predicting how polycrystalline ice fractures at laboratory and even geophysical length scales.

Effect of Laser Energy on Anisotropic Material Properties of a Novel Austenitic Stainless Steel with a Fine-Grained Microstructure

Laser powder bed fusion (LPBF) provides a novel approach with high complexity and freedom for material processing and design, and its special thermal history endows the material with anisotropic properties. By adding micro-alloying elements Nb and Ti into conventional 316L, the anisotropy of the novel austenitic stainless steel fabricated by LPBF, which is related to the laser heat input, was investigated. The refined microstructure of this steel was further strengthened with in situ-generated Nb-, Cr-, and Ti-rich nanoprecipitates at a specific location. The heat input affects the material anisotropy, and a lower heat input leads to stronger anisotropy in this steel. The as-built parts at a low heat input in the horizontal and vertical planes exhibited finer microstructures compared to those fabricated at a high heat input. The epitaxial growth of the grains associated with the thermal gradient resulted in the vertical-section grain size being generally larger than that of the horizontal section. As a result, the low-heat-input parts with a finer grain are also stronger in the horizontal direction, with yield and tensile strengths approaching 0.9 and 1.2 GPa, respectively. Meanwhile, the microstructural changes due to the high heat input imparted a better ductility of parts in different sections (a 3.15% and 4.4% increase in the horizontal and vertical directions, respectively). Its mechanical properties depend mainly on the direction of stress coupled with intergranular friction during deformation in both coarse and fine grains.