Coarse Grain Research Articles

Enhanced cryogenic mechanical properties of heterostructured CrCoNi multicomponent alloy: Insights from in-situ neutron diffraction

Heterostructured materials (HSMs) has been shown to improve the strength-ductility trade-off of conventional alloys but their cryogenic performance has not been studied during real-time deformation. We investigated heterostructured CrCoNi medium-entropy alloy by in-situ neutron diffraction at cryogenic (77 K) and room (293 K) temperatures. The significant mechanical mismatch at interfaces between fine and coarse grains, due to pronounced grain size disparity, resulted in exceptional yield strength of 918 MPa at 293 K. The yield strength further increased to 1244 MPa at 77 K with an excellent uniform elongation of 34 %. The exceptional strength–ductility combination at 77 K can be attributed to enhanced geometrically necessary dislocation pile-up density boosted from high-mechanical mismatch interfaces, as well as higher planar faults, and martensitic phase transformation. Comparison with homogenous counterparts demonstrates the potential of HSMs as a new strategy to improve the mechanical performance of different materials, including medium-/high-entropy alloys for cryogenic applications.

Sintering process optimization of the additively manufactured pure copper parts through the metal paste deposited process

The fabrication process, sintering cycles through two sintering methods, microstructural and texture characterization, mechanical properties, and electrical conductivity of metal paste-deposited copper parts were investigated in this study. In the first condition, samples were air-debinded for carbon content removal followed by a sintering cycle. A sintering profile with the maximum sintering temperature and time of 1080 °C and 1 hr. was implemented after performing the air-debinding cycle at 250 °C for 2 hrs. In the second condition, samples were sintered in the environment of copper oxide for carbon removal in the early stages of the sintering cycle, i.e., 1070 °C for 1 hr and 1080 °C for 1, 2, and 3 hrs. The microstructural observations revealed coarser grains in the air-debinded samples, perhaps due to additional generated heat during carbon oxide formation, which may produce destructive effects on the boundary (HAGBs, twins, and CSL) volume and densification behavior of copper parts. However, through the second method, much finer grains and higher densities of boundaries were detected in the microstructure. Despite the significant effect of sintering conditions on the microstructure, texture interpretations revealed minor changes in the pole figures for different situations. Using the second sintering method and owing to the less carbon content and based on the density of the boundaries and their configurations, higher electrical conductivity (98.4±1.3 % IACS) was recorded by sintering the green parts. The comparison between the data from this study with other parts printed through other additive manufacturing techniques demonstrated a superior electrical conductivity level and acceptable balance between strain and strain notably with the sample sintered for 3 hrs.

Analysis of mapping atomic models to coarse-grained resolution.

Low-resolution coarse-grained (CG) models provide significant computational and conceptual advantages for simulating soft materials. However, the properties of CG models depend quite sensitively upon the mapping, M, that maps each atomic configuration, r, to a CG configuration, R. In particular, M determines how the configurational information of the atomic model is partitioned between the mapped ensemble of CG configurations and the lost ensemble of atomic configurations that map to each R. In this work, we investigate how the mapping partitions the atomic configuration space into CG and intra-site components. We demonstrate that the corresponding coordinate transformation introduces a nontrivial Jacobian factor. This Jacobian factor defines a labeling entropy that corresponds to the uncertainty in the atoms that are associated with each CG site. Consequently, the labeling entropy effectively transfers configurational information from the lost ensemble into the mapped ensemble. Moreover, our analysis highlights the possibility of resonant mappings that separate the atomic potential into CG and intra-site contributions. We numerically illustrate these considerations with a Gaussian network model for the equilibrium fluctuations of actin. We demonstrate that the spectral quality, Q, provides a simple metric for identifying high quality representations for actin. Conversely, we find that neither maximizing nor minimizing the information content of the mapped ensemble results in high quality representations. However, if one accounts for the labeling uncertainty, Q(M) correlates quite well with the adjusted configurational information loss, Îmap(M), that results from the mapping.

Dietary patterns related to attention and physiological function in high-altitude migrants.

High altitude exposure negatively affects human attentional function. However, no studies have explored the regulation of attentional and physiological functions from a dietary perspective. A total of 116 Han Chinese students from Tibet University who were born and raised in a plain area and had been living in Tibet for > 2 years were recruited. All participants were male migrants. A food frequency questionnaire, complete blood count, and attention network test were performed on the participants. Pearson's correlation was applied to assess the reliability and validity of the food frequency questionnaire. Principal component analysis was utilized to extract dietary patterns. A linear mixed model was employed to account for individual differences. The results showed that the five main dietary patterns were coarse grain, alcohol, meat, protein, and snacking dietary patterns. Furthermore, individuals who adhered to the coarse grain dietary pattern and had high mean corpuscular hemoglobin showed better attentional performance. Individuals with high alcohol consumption and systemic immune-inflammation index levels exhibited worse attentional performance. These findings imply that high-altitude migrants should include more coarse grains in their daily diet and avoid excessive alcohol consumption to improve attention.

Coarse-Graining the Recognition of a Glycolipid by the C-Type Lectin Mincle Receptor.

Macrophage inducible Ca2+-dependent lectin (Mincle) receptor recognizes Mycobacterium tuberculosis glycolipids to trigger an immune response. This host membrane receptor is thus a key player in the modulation of the immune response to infection by M. tuberculosis and has emerged as a promising target for the development of new vaccines against tuberculosis. The recent development of the Martini 3 force field for coarse-grained (CG) molecular modeling allows the study of interactions of soluble proteins with small ligands which was not typically modeled well with the previous Martini 2 model. Here, we present a refined approach detailing a protocol for modeling interactions between a glycolipid and its receptor at a CG level using the Martini 3 force field. Using this approach, we studied Mincle and identified critical parameters governing ligand recognition, such as loop flexibility and the regulation of hydrophobic groove formation by calcium ions. In addition, we assessed ligand affinity using free energy perturbation calculations. Our results offer mechanistic insight into the interactions between Mincle and glycolipids, providing a basis for the rational design of molecules targeting this type of membrane receptors.

Study on Dynamic Recrystallization under Thermal Cycles in the Process of Direct Energy Deposition for 316 L Austenitic Stainless Steel

In the process of directed energy deposition (DED), the grain structure of the deposited samples is determined by two aspects. The first is the initial solidification grain structure; the second is the effect of the upper thermal cycle on the solidified grain structure of the lower layer. Dynamic recrystallization and grain growth can be activated under suitable strain and the temperature resulting from thermal cycles. The evolution of grain size and the geometric dislocation density (GND) of austenitic stainless steel 316 L under different strains and temperatures caused by thermal cycles was investigated. It is found that dynamic recrystallization requires an appropriate level of accumulated strain, temperature, and initial grain size. Under <2% accumulated strain and 400–1200 °C conditions caused by 30 layers of thermal cycles, fully dynamic recrystallization occurs with coarse initial grains (CIG), leading to the complete coarsening of grains. However, relatively fine initial grains (FIG) under the same conditions only display partial dynamic recrystallization. The next 2–4% strain and 400–700 °C by 60 layers of thermal cycles make up the driving force of fully dynamic recrystallization, and the grains coarsen completely. Larger accumulated strain (4–6%) and lower temperature (400–600 °C) by 90 layers of thermal cycles and FIG provide more nucleation sites for dynamic recrystallization, which leads to little coarsening of grains even after fully dynamic recrystallization. Temperature, accumulated strain, and the amount of δ-ferrite promote the formation of sub-grains during dynamic recrystallization caused by thermal cycles, which leads to the increase in GND.

A bimodal and heterogeneous laminate structure with alternately distributed copper-base and nickel-base alloys via multi-material laser powder bed fusion (MM-LPBF) additive manufacturing

A micro-laminated bimodal heterostructure with alternately distributed copper-base and nickel-base alloys was additively manufactured via the multi-material laser powder bed fusion (MM-LPBF) technique. The high melting point elements such as nickel act as the heterogeneous nucleation sites for the copper melt, promoting the generation of ultrafine grains and forming a multi-layered structure with alternating coarse and fine grains. The differentiated grain size, shape and orientation in the bimodal heterostructure lead to the diversity of deformation mechanisms in different localized areas, which helps to achieve the internal stress gradient distribution and plastic deformation harmonization, thereby overcoming the strength-ductility trade-off for the overall structure. This work provides a novel fabrication path and experimental basis for understanding bimetallic laminated heterostructures.

Knowledge, Behavior, and Influencing Factors of Coarse Grain Consumption among Chinese Adults: A Focus Group Study in Xi’an

BackgroundCoarse grains are rich in fiber, minerals, and other beneficial nutrients but are consumed at low levels in modern populations. The factors that influence coarse grain consumption in current living and dietary environments are not fully understood. ObjectiveThis study aimed to explore the knowledge and behavior related to coarse grain consumption and identify the influencing factors among Chinese citizens. MethodSix focus group discussions were conducted with 39 participants aged 18–65 years from diverse social backgrounds in Xi'an, China. All discussions were transcribed verbatim and analyzed using inductive thematic analysis. ResultsThe majority of participants demonstrated insufficient knowledge about coarse grains, including their definitions, health benefits, and recommended intake. A small number of the participants reported regular consumption. The barriers to coarse grain consumption were poor sensory properties, insufficient cooking skills and time, limited availability of ready-to-eat foods, established dietary habits, and high price. Additionally, the new barriers included psychological burden, concerns about food safety, the impact of processing methods on health benefits, and special health conditions. Health benefits and family influence emerged as the two primary factors motivating coarse grain consumption. Most participants expressed a positive attitude toward partially replacing staple foods with coarse grains. Enhancing health education, innovating food processing methods, improving labeling systems, and strengthening safety supervision have been recommended for increasing coarse grain consumption. ConclusionA gap exists between health awareness and healthy behaviors regarding in coarse grain consumption, thus, collaborative efforts among government agencies, educational institutions, nutrition societies, the food industry, policymakers, and health professionals are essential to overcome these challenges.

Mitigating adverse effects of Cu-containing intrauterine devices using a highly biocompatible Cu[sbnd]5Fe alloy

Copper-containing intrauterine devices (Cu-IUD) are adopted by worldwide women for contraception with the advantages of long-term effectiveness, reversibility and affordability. However, adverse effects occur in the initial implantation stage of Cu-IUD in uterine because of the burst release of Cu2+. To minimize the burst release, in this study, we designed a series of Cu–Fe alloys with 0.5 wt%, 1 wt% and 5 wt% Fe and also further produced ultrafine grained (UFG) structure for these alloys via equal-channel angular pressing. The microstructures and properties of the coarse grained (CG) Cu, CG Cu–Fe alloys and UFG Cu–Fe alloys were systematically investigated, including grain structure and phase compositions, metallic ions release behavior, electrochemical corrosion performance, and in vitro cytotoxicity. With careful comparison and selection, we chose the CG Cu–5Fe and UFG Cu–5Fe for in vivo tests using rat model, including tissue biocompatibility, in vivo corrosion behavior, and contraceptive effectiveness. Moreover, the corrosion mechanism of the Cu–5Fe alloy and its improved biocompatibility was discussed. Both CG and UFG Cu–5Fe alloys exhibited dramatic suppression of Cu2+ release in simulated uterine fluid for the long-term immersion process. The in vivo tissue compatibility was significantly improved with both CG and UFG Cu–5Fe alloys implanted in the rats’ uterine while the high contraceptive efficacy was well maintained. Due to the superior biocompatibility, the CG and UFG Cu–5Fe alloys can be the promising candidate material for Cu-IUD. Statement of significanceA highly biocompatible Cu–Fe alloy was designed and fabricated for Cu-containing intrauterine devices (Cu-IUD). With 5 wt% Fe, the burst release of Cu2+ is inhibited due to the formed galvanic cell of Cu and Fe, resulting in earlier release of Fe3+. As Fe is the most abundant essential trace element of human body, it can mitigate the toxic effects of Cu2+, thus significantly improving both in vitro cell compatibility and in vivo tissue compatibility. More importantly, the Cu–5Fe alloy exhibits 100 % contraceptive efficiency as the CG Cu, but with greatly reduced adverse effects to the uterus tissues. An advanced Cu-IUD can be developed using Cu–Fe alloys.

Microstructural evolution and dynamic recrystallization mechanisms of additively manufactured TiAl alloy with heterogeneous microstructure during hot compression

Microstructural evolution and dynamic recrystallization (DRX) mechanisms of a Ti−48Al−2Cr−2Nb (at.%) alloy prepared by selective electron beam melting (SEBM) during hot deformation at 1150 °C and 0.1 s−1 were investigated by hot compression tests, optical microscope (OM), scanning electron microscope (SEM), electron back-scattered diffraction (EBSD) and transmission electron microscope (TEM). The results show that the initial microstructure of the as-SEBMed alloy exhibits layers of coarse γ grains and fine γ+α2+(α2/γ) lamellar mixture grains alternately along the building direction. During the early stage of hot deformation, deformation twins tend to form within the coarse grains, facilitating subsequent deformation, and a small number of DRX grains appear in the fine-grained regions. With the increase of strain, extensive DRX grains are formed through different DRX mechanisms in both coarse and fine-grained regions, involving discontinuous dynamic recrystallization mechanism (DDRX) in the fine-grained regions and a coexistence of DDRX and continuous dynamic recrystallization (CDRX) in the coarse- grained regions.

Crystallographic Study of Transformation Products of Heat-Affected Zone and Correlation with Properties of FH690 Heavy-Gauge Marine Steel by Multi-Pass Submerged Arc Welding

In this work, the microstructure–property relationship of the heat-affected zone (HAZ) of a FH690 ultra-heavy marine steel plate was investigated based on insight of microstructure and crystallographic features. After multi-pass welding with a heat input of ~30 kJ/cm, an ~8 mm wide HAZ was obtained with a coarse grain HAZ (CGHAZ) of ~3.8 mm, fine grain HAZ (FGHAZ) of ~3.4 mm, and intercritical HAZ (ICHAZ) of ~1 mm. High impact toughness values of ~120 and 140 J at -60 °C were obtained for coarse grain HAZ and fine grain HAZ, respectively. The microstructure of the CGHAZ and FGHAZ was fine lath bainite. Although the average prior austenite grain size for the CGHAZ was ~75 μm, which was five times that of the FGHAZ (15 μm), a high density of high-angle grain boundaries (HAGBs) with misorientation higher than 45° was obtained in the CGHAZ. This is the underlying reason for the excellent low-temperature toughness of the HAZ. Thermo-dynamic calculations indicated that the high density of HAGBs in the CGHAZ was attributed to the decreased bainitic transformation temperature due to the reduced phase transformation driving force via the high nickel addition, leading to weak variant selection. In addition, the high nickel addition offered high hardenability for high hardness in the FGHAZ. The outcome of this study could provide an experimental and fundamental basis for designing high-strength ultra-heavy steel plates with excellent weldability.

Improving comprehensive properties of Cu−11.9Al−2.5Mn shape memory alloy by adding multi-layer graphene carried by Cu51Zr14 inoculant particles

In order to improve the comprehensive properties of the Cu−11.9Al−2.5Mn shape memory alloy (SMA), multilayer graphene (MLG) carried by Cu51Zr14 inoculant particles was incorporated and dispersed into this alloy through preparing the preform of the cold-pressed MLG−Cu51Zr14 composite powders. In the resultant novel MLG/Cu−Al−Mn composites, MLG in fragmented or flocculent form has a good bonding with the Cu−Al−Mn matrix. MLG can prevent the coarsening of grains of the Cu−Al−Mn SMA and cause thermal mismatch dislocations near the MLG/Cu−Al−Mn interfaces. The damping and mechanical properties of the MLG/Cu−Al−Mn composites are significantly improved. When the content of MLG reaches 0.2 wt.%, the highest room temperature damping of 0.0558, tensile strength of 801.5 MPa, elongation of 10.8%, and hardness of HV 308 can be obtained. On the basis of in-depth observation of microstructures, combined with the theory of internal friction and strengthening and toughening theories of metals, the relevant mechanisms are discussed.

Mechanical property, corrosion behavior and cytocompatibility of CoCrMo for dental application: A comparative study of cast and laser powder bed fusion

In this work, by employing powders sourced directly from the original ingot for additive manufacturing, we enabled a comparative overview of the performance between CoCrMo manufactured via laser powder bed fusion (LPBF) and those in their original cast condition. Microstructural analysis revealed that the cast (CT) alloy predominantly consisted of coarse grains with distribution of sigma phase, while the LPBF process resulted in a refined grain structure devoid of the sigma phase. The tensile strength tests demonstrated that the LPBF-derived CoCrMo alloy had substantially greater tensile strength, and ductility compared to CT alloy. Corrosion tests indicated superior corrosion resistance in the LPBF alloy, albeit with a lower metal ion release. In vitro assays confirmed that LPBF CoCrMo alloys displayed favorable cytocompatibility. Consequently, it is concluded that the CoCrMo alloy processed through laser powder bed fusion exhibited enhanced mechanical performance and corrosion resistance. These improvements are primarily attributed to the transformation of the original coarse columnar grain structure through the LPBF technique.

Unleashing the elastocaloric cooling potential of 3D-printed NiTi alloy with heterogeneous microstructures and Ni4Ti3 nanoparticles

Toward the development of elastocaloric (eC) refrigeration applications, this study examines how Ni4Ti3 nanoparticles improve the eC properties of laser powder bed-fused (LPBF) NiTi alloys, with a focus on the formation of a NiTi/Ni4Ti3 nanocomposite. The LPBF-produced microstructure offers significant advantages: i) a heterogeneous grain structure that provides complementary benefits—fine grains offer higher deformation resistance while coarse grains initiate phase transformation (PT) earlier, releasing more latent heat; ii) a strong <001>//building direction texture that enhances recoverability. However, these benefits are partially limited by grain boundary slip during PT, leading to lower cooling efficiency and increased energy dissipation in as-built NiTi alloys. To address these issues, Ni4Ti3 nanoparticles are introduced through aging treatment, forming a composite structure that strengthens grain boundaries. Given the challenges of applying severe plastic deformation to 3D-printed components, this approach may offer a more practical solution. The study also reveals that Ni4Ti3 nanoparticles contribute to: 1) reducing Ni content in the matrix, increasing lattice size and enthalpy, which enhances the temperature drop (ΔTad); and 2) promoting R phase formation, which hinders the B2↔B19' PT, reducing energy dissipation and improving the coefficient of performance (COPmat). The balance of these effects depends on nanoparticle size, with smaller particles (∼5–12 nm) amplifying the second effect, while larger particles (∼130 nm) increase the first effect. At 350°C aging, the optimized nanocomposite exhibits a maximum COPmat of 15 and ΔTad of 14K, representing a 163% improvement over the as-built alloy. This work highlights the potential of NiTi composites in 3D-printed eC components.

Mechanical and microstructural profiling of additively manufactured cobalt–nickel functional gradient structure

In this study, a functional gradient material (FGM) structure composed of a nickel alloy (IN718), and a cobalt alloy (CoCrMo) was additively manufactured using a co-axial powder-fed laser-directed energy deposition (L-DED) system. The high manufacturing flexibility of L-DED enabled the seamless deposition of IN718-CoCrMo FGM structure through interfacial bonding driven by thermal gradient and cool-down mechanisms. Microscopic analysis confirmed the absence of cracks or delamination in the CoCrMo-IN718 interfacial bonding region. The SEM-EBSD microstructural analysis and micro-hardness testing were performed on the as-printed CoCrMo-IN718 FGM primarily to correlate the hardness properties-microstructural grain phase morphology between the parent alloys and their interfacial bonding region. It was observed that the average hardness of the CoCrMo-IN718 interface zone (322.83 HV1) fell between IN718 (268.67 HV1) and CoCrMo (359.75 HV1) regions. The EBSD analysis reports indicated that along the build direction of CoCrMo-IN718 FGM, the preferential grain orientation aligned in [100] with grain structure transitioning from equiaxed → columnar → elongated columnar dendrites → equiaxed grain, predominantly comprised of face-centered cubic (FCC)-gamma (γ) phase crystal structures. Relatively, coarser grain structures were observed in the interface bonding region, attributed to the analogous crystallography space groups, and prolonged localized thermal gradients.

Relationship between grain structure evolution and tensile anisotropy in Al-Zn-Mg-Cu cylindrical part formed by additive friction stir deposition

The thick-walled Al-Zn-Mg-Cu cylindrical part was obtained by additive friction stir deposition, and the relationship between grain structure evolution and tensile anisotropy was investigated in detail. The intra-layer grains are significantly refined due to continuous dynamic recrystallization (CDRX), and the grains at the interface are further refined by 30%-45% due to geometric dynamic recrystallization (GDRX). The early cracking and ductility deterioration under Z direction loading are caused by strain localization due to coarse and fine grain distribution and pre-existing strain at the interface. The grain growth rates for specific orientations (Cube, P, Q, and Rotated Goss) are higher than average, and the mismatch in elastic modulus between these grown grains and the matrix results in ductility differences in the X and Y directions. Texture components and residual stresses affect yield strength in the X and Y directions. Meanwhile, dissolution of η/η' and the coarsening of the particles due to the thermal cycling effect leads to a decrease in the yield strength in the building direction. The average ultimate tensile strength (UTS) and elongation (El) of the part could reach 370 MPa and 20%, respectively. The tensile properties of the as-deposited Al-Zn-Mg-Cu cylindrical part are generally higher than those of melt-based additive manufacturing, but lower than those of the extruded and forged states due to the dissolution and coarsening of the strengthening precipitates during thermal cycling.

Demographic and food frequency survey of a marginalized community in Almora, Uttarakhand, India

The demography and eating behaviour of the marginalized communities residing in the Almora district of Uttarakhand, India, was investigated. It was observed that agriculture was the main income source along with other work such as labourer, black-smith, etc. Food consumption was mainly dependent upon either the Government Public Distribution System or on traditional coarse grains which were being produced only for their own consumption. Traditional food crops were being neglected in the Himalayan region due to the deterioration of local food systems, changing food habits, and lack of awareness of the uses and nutritional value of traditional crops.

Preparation of Cu nanolayers by magnetic field-assisted electrodeposition and research on the nucleation and growth mechanism

Electrodeposition technology is widely used in the surface treatment of copper foil, and the core of this technology is roughening and curing treatment. During the electrodeposition process, the deposited layers often exhibits some problems, such as coarse grain size, uneven thickness and difficult control of crystal morphology. The magnetohydrodynamic (MHD) effect of magnetic field can obviously control the electrodeposition of Cu and improve the micro-morphology and performance of deposited layers. In this paper, Linear Sweep Voltammetry (LSV), Cyclic Voltammetry (CV) and Chronocoulometry (CC) curves were adopted to investigate the electrochemical behavior of deposited Cu in ultra-high acidity sulfate systems under different magnetic field conditions. The nucleation and growth mechanism were discussed, and the micro-morphology of deposited layers was analyzed. The results show that the electrodeposition of Cu follows the three-dimensional (3D) growth mechanism of progressive nucleation and diffusion control under the static condition, and the deposits appear cylindrical shape formed by spherical agglomerated. The magnetic field significantly improves the mass transfer rate, and the deposited layers will be more uniform and dense, following 3D growth mechanism under the electrochemical control. With the increasing of magnetic field intensity, the nucleation mechanism gradually shifts from progressive to transient nucleation. At the early stage of nucleation, the high-intensity magnetic field can significantly increase the number of grains and refine them, obtaining uniform and dense deposited nanolayers.

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.