Pub Date : 2024-09-24DOI: 10.1016/j.jmrt.2024.09.189
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.
{"title":"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","authors":"","doi":"10.1016/j.jmrt.2024.09.189","DOIUrl":"10.1016/j.jmrt.2024.09.189","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.jmrt.2024.09.198
In this study, we report a novel high-Mn Fe–21Mn–6Al–4Si–1C (wt.%) duplex lightweight steel with concurrent chemical ordering and twinning-induced plasticity effects. This steel is capable of achieving an exceptional combination of strength and ductility following either cold-rolling and annealing at 1000 °C or subsequent short-term aging at 550 °C. In its as-annealed state, this steel primarily consists of γ-austenite and α-ferrite, with α-ferrite appearing as dispersed particles within fully recrystallized γ grains. Furthermore, L′12- and D03-type ordered nanodomains exist within these two phases, respectively. The aging treatment negligibly affects the size and volume fraction of both the γ-austenite and α-ferrite, yet it enhances the degree of ordering as well as the size and volume fraction of their ordered nanodomains, leading to a rise in yield strength from ∼800 to ∼1062 MPa and a decline in total elongation from ∼60.4% to ∼44.4%. The high yield strength of this steel originates from multiple strengthening mechanisms involving dislocation interactions with solute atoms, ordered nanodomains, γ grain boundaries and γ/α phase boundaries. This steel plastically deforms via planar slip during the initial stages. The rather small γ grain size, coupled with the presence of hard α-ferrite particles, fosters the dynamic slip band refinement (DSBR) effect, thereby enhancing the flow stress sufficiently to trigger deformation twinning in the steel during the later stages. The DSBR effect, combined with the progressive formation of deformation twins, stacking faults and Lomer-Cottrell locks, imparts pronounced strain hardenability to this steel, leading to its outstanding ductility.
{"title":"A novel high-Mn duplex twinning-induced plasticity lightweight steel with high yield strength and large ductility","authors":"","doi":"10.1016/j.jmrt.2024.09.198","DOIUrl":"10.1016/j.jmrt.2024.09.198","url":null,"abstract":"<div><div>In this study, we report a novel high-Mn Fe–21Mn–6Al–4Si–1C (wt.%) duplex lightweight steel with concurrent chemical ordering and twinning-induced plasticity effects. This steel is capable of achieving an exceptional combination of strength and ductility following either cold-rolling and annealing at 1000 °C or subsequent short-term aging at 550 °C. In its as-annealed state, this steel primarily consists of γ-austenite and α-ferrite, with α-ferrite appearing as dispersed particles within fully recrystallized γ grains. Furthermore, L′1<sub>2</sub>- and D0<sub>3</sub>-type ordered nanodomains exist within these two phases, respectively. The aging treatment negligibly affects the size and volume fraction of both the γ-austenite and α-ferrite, yet it enhances the degree of ordering as well as the size and volume fraction of their ordered nanodomains, leading to a rise in yield strength from ∼800 to ∼1062 MPa and a decline in total elongation from ∼60.4% to ∼44.4%. The high yield strength of this steel originates from multiple strengthening mechanisms involving dislocation interactions with solute atoms, ordered nanodomains, γ grain boundaries and γ/α phase boundaries. This steel plastically deforms via planar slip during the initial stages. The rather small γ grain size, coupled with the presence of hard α-ferrite particles, fosters the dynamic slip band refinement (DSBR) effect, thereby enhancing the flow stress sufficiently to trigger deformation twinning in the steel during the later stages. The DSBR effect, combined with the progressive formation of deformation twins, stacking faults and Lomer-Cottrell locks, imparts pronounced strain hardenability to this steel, leading to its outstanding ductility.</div></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-23DOI: 10.1016/j.jmrt.2024.09.178
An effective method for fabricating copper-nickel bimetallic liquid rocket engine thrust chambers involves utilizing laser directed energy deposition (LDED) technology. However, the state of the substrate surface significantly impacts the LDED process. This study investigates the effects of various substrate treatments on LDED single tracks, using CuCr0.8 high-copper alloy as the substrate and Inconel 718 as the deposition material. The treatments include polishing, sandblasting, laser etching, and cold spraying. Substrate surface roughness, laser absorptivity, molten pool morphology, and microstructure were characterized, and the mechanisms of laser absorptivity change and the different LDED processes were analyzed. The results indicate that the laser-etched surface exhibits the worst surface roughness (Ra 15.20 ± 0.60 μm), the highest laser absorptivity(80.70% at 1080 nm wavelength), the largest deposition width (947.33 ± 29.85 μm), and the maximum number of fine grains among the four substrates. Additionally, the cold-sprayed surface shows the largest deposition depth (237.33 ± 39.04 μm), the minimum number of fine grains and a higher laser absorptivity (66.20% at 1080 nm wavelength). In situ observations of molten pool formation and flow during LDED was conducted using an in situ high-speed high-resolution imaging system. The mechanisms underlying the alteration in laser absorptivity primarily involve the "trapped light" effect and modifications to the surface material. This research is significant as it provides foundational insights for laser processing of highly reflective materials, offering important theoretical and practical implications for engineering applications.
{"title":"Influence of laser absorptivity of CuCr0.8 substrate surface state on the characteristics of laser directed energy deposition inconel 718 single track","authors":"","doi":"10.1016/j.jmrt.2024.09.178","DOIUrl":"10.1016/j.jmrt.2024.09.178","url":null,"abstract":"<div><div>An effective method for fabricating copper-nickel bimetallic liquid rocket engine thrust chambers involves utilizing laser directed energy deposition (LDED) technology. However, the state of the substrate surface significantly impacts the LDED process. This study investigates the effects of various substrate treatments on LDED single tracks, using CuCr0.8 high-copper alloy as the substrate and Inconel 718 as the deposition material. The treatments include polishing, sandblasting, laser etching, and cold spraying. Substrate surface roughness, laser absorptivity, molten pool morphology, and microstructure were characterized, and the mechanisms of laser absorptivity change and the different LDED processes were analyzed. The results indicate that the laser-etched surface exhibits the worst surface roughness (Ra 15.20 ± 0.60 μm), the highest laser absorptivity(80.70% at 1080 nm wavelength), the largest deposition width (947.33 ± 29.85 μm), and the maximum number of fine grains among the four substrates. Additionally, the cold-sprayed surface shows the largest deposition depth (237.33 ± 39.04 μm), the minimum number of fine grains and a higher laser absorptivity (66.20% at 1080 nm wavelength). In situ observations of molten pool formation and flow during LDED was conducted using an in situ high-speed high-resolution imaging system. The mechanisms underlying the alteration in laser absorptivity primarily involve the \"trapped light\" effect and modifications to the surface material. This research is significant as it provides foundational insights for laser processing of highly reflective materials, offering important theoretical and practical implications for engineering applications.</div></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.jmrt.2024.09.163
Lightweight bulletproof plate is highly demanded in the field of security field. A novel plate of carbon fiber reinforced plate (CFRP)/aramid filament bundles (AFB) sandwich plate is manufactured through winding methods in this paper. The ballistic performance is evaluated and failure mechanism is explored on the designed six CFRP/AFB sandwich plates. It is found that the sandwich structure of 3-4 × 16 is the best structure by comprehensively considering the energy absorption, Coefficient of Variation(CV) and shaping difficulty, of which the and the average energy absorption are 225.26 m/s and 150.60 J, respectively. In addition, for the case that the number of filaments in the first entanglement is more and the number of first entanglement in the secondary entanglement is less, the ballistic performance would be better. To the failure mechanism, the upper CFRP is damaged by shear failure and the bottom CFRP shows delamination and separation in the impact process. The filament bundle plate in the core layer is benefit in resistance to projectile impact and it fails mainly by the disintegration and bending. This novel CFRP/AFB sandwich plate is a new direction for producing ballistic proof plate.
{"title":"Experimental study on the ballistic performance of CFRP/AFB sandwich plate","authors":"","doi":"10.1016/j.jmrt.2024.09.163","DOIUrl":"10.1016/j.jmrt.2024.09.163","url":null,"abstract":"<div><div>Lightweight bulletproof plate is highly demanded in the field of security field. A novel plate of carbon fiber reinforced plate (CFRP)/aramid filament bundles (AFB) sandwich plate is manufactured through winding methods in this paper. The ballistic performance is evaluated and failure mechanism is explored on the designed six CFRP/AFB sandwich plates. It is found that the sandwich structure of 3-4 × 16 is the best structure by comprehensively considering the energy absorption, Coefficient of Variation(CV) and shaping difficulty, of which the <span><math><mrow><msub><mi>v</mi><mn>50</mn></msub></mrow></math></span> and the average energy absorption are 225.26 m/s and 150.60 J, respectively. In addition, for the case that the number of filaments in the first entanglement is more and the number of first entanglement in the secondary entanglement is less, the ballistic performance would be better. To the failure mechanism, the upper CFRP is damaged by shear failure and the bottom CFRP shows delamination and separation in the impact process. The filament bundle plate in the core layer is benefit in resistance to projectile impact and it fails mainly by the disintegration and bending. This novel CFRP/AFB sandwich plate is a new direction for producing ballistic proof plate.</div></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.jmrt.2024.09.171
High-entropy alloys are widely used as structural materials and hold potential as functional materials. This study aims to develop a soft magnetic medium entropy alloy FeCoNiSi0.2 (Si0.2 MEA) with excellent soft magnetic properties and higher ductility using additive manufacturing technology. The microstructure of Si0.2 MEA is characterized by texture and large grains, with a single FCC phase structure. The texture strength of MEA initially increases and then decreases with the addition of Si, with Si0.1 MEA exhibiting the strongest fiber texture. Among the four FeCoNiSix MEAs, Si0.2 MEA demonstrates the best tensile properties (i.e. δ ∼39 %, σ0.2–287 MPA, σb∼551 MPa). The correlation generalized stacking fault energy calculation model indicates that Si0.2 MEA has the lowest generalized stacking fault energy (∼7 mJ/m2), suggesting superior ductility. The synergistic effect of texture and large grains promotes the formation of a magnetization “easy axis”, which makes Si0.2 MEA exhibit the best soft magnetic properties (Ms:150emu/g, Hc:1.04Oe). These results provide a new paradigm for developing laser additively manufactured soft magnetic medium entropy alloy.
高熵合金被广泛用作结构材料，并具有作为功能材料的潜力。本研究旨在利用快速成型技术开发一种具有优异软磁性能和更高延展性的软磁中熵合金 FeCoNiSi0.2 (Si0.2 MEA)。Si0.2 MEA 的微观结构以纹理和大晶粒为特征，具有单 FCC 相结构。MEA 的纹理强度最初随着 Si 的添加而增加，然后降低，其中 Si0.1 MEA 的纤维纹理强度最高。在四种 FeCoNiSix MEA 中，Si0.2 MEA 的拉伸性能最好（即 δ∼39 %，σ0.2-287 MPA，σb∼551 MPa）。相关的广义堆积断层能计算模型表明，Si0.2 MEA 的广义堆积断层能最低（∼7 mJ/m2），这表明其延展性更好。纹理和大晶粒的协同作用促进了磁化 "易轴 "的形成，从而使 Si0.2 MEA 表现出最佳的软磁特性（Ms:150emu/g，Hc:1.04Oe）。这些结果为开发激光添加制造的软磁中熵合金提供了新的范例。
{"title":"Additively manufactured FeCoNiSi0.2 alloy with excellent soft magnetic and mechanical properties through texture engineering","authors":"","doi":"10.1016/j.jmrt.2024.09.171","DOIUrl":"10.1016/j.jmrt.2024.09.171","url":null,"abstract":"<div><div>High-entropy alloys are widely used as structural materials and hold potential as functional materials. This study aims to develop a soft magnetic medium entropy alloy FeCoNiSi<sub>0.2</sub> (Si<sub>0.2</sub> MEA) with excellent soft magnetic properties and higher ductility using additive manufacturing technology. The microstructure of Si<sub>0.2</sub> MEA is characterized by texture and large grains, with a single FCC phase structure. The texture strength of MEA initially increases and then decreases with the addition of Si, with Si<sub>0.1</sub> MEA exhibiting the strongest fiber texture. Among the four FeCoNiSi<sub>x</sub> MEAs, Si<sub>0.2</sub> MEA demonstrates the best tensile properties (i.e. δ ∼39 %, σ<sub>0.2</sub>–287 MPA, σ<sub>b</sub>∼551 MPa). The correlation generalized stacking fault energy calculation model indicates that Si<sub>0.2</sub> MEA has the lowest generalized stacking fault energy (∼7 mJ/m<sup>2</sup>), suggesting superior ductility. The synergistic effect of texture and large grains promotes the formation of a magnetization “easy axis”, which makes Si<sub>0.2</sub> MEA exhibit the best soft magnetic properties (M<sub>s</sub>:150emu/g, H<sub>c</sub>:1.04Oe). These results provide a new paradigm for developing laser additively manufactured soft magnetic medium entropy alloy.</div></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1016/j.jmrt.2024.09.121
The effects of sintering temperatures on the microstructures and mechanical properties of titanium carbide particles reinforced iron matrix composites (TiC/Fe MCs) fabricated by the spark plasma sintering (SPS) process with pure element powders have been systematically investigated. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron back scattering diffractometer (EBSD), and energy dispersive spectroscopy (EDS) have been conducted for microstructural analysis. The results show that with increasing sintering temperatures, the porosity of the composites initially decreases and then increases. Simultaneously, the grain size gradually diminishes while element diffusion becomes more uniform. Upon reaching a critical sintering temperature (1120 °C), the original grain size disappears and carbides undergo decomposition and reprecipitation to reach an equilibrium state, with which optimal comprehensive properties can be achieved (porosity decreases to a minimum of 3.85%, grain size of 2.69 μm, Vickers hardness reaches 595 HV0.5, bending strength is at 662 MPa, coefficient of friction is at 0.74, and wear loss to 0.21 mg). These property enhancements have been attributed to reduced porosity in the composites, decreased grain size, and improved anchoring effect of carbides within the matrix. Additionally, the primary fracture mechanisms and wear mechanisms of TiC/Fe MCs with different process parameters have been analyzed. When the temperature is below 1080 °C, intergranular fracture predominates, whereas transgranular and ductile fractures become predominant above this threshold. When the temperature is below 1120 °C, fatigue wear, oxidation wear, and abrasive wear are predominantly observed. Conversely, when the temperature exceeds 1120 °C, oxidation wear and abrasive wear become the primary mechanisms.
{"title":"Effect of temperature on the microstructure and mechanical properties of TiC/Fe matrix composites fabricated by spark plasma sintering","authors":"","doi":"10.1016/j.jmrt.2024.09.121","DOIUrl":"10.1016/j.jmrt.2024.09.121","url":null,"abstract":"<div><p>The effects of sintering temperatures on the microstructures and mechanical properties of titanium carbide particles reinforced iron matrix composites (TiC/Fe MCs) fabricated by the spark plasma sintering (SPS) process with pure element powders have been systematically investigated. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron back scattering diffractometer (EBSD), and energy dispersive spectroscopy (EDS) have been conducted for microstructural analysis. The results show that with increasing sintering temperatures, the porosity of the composites initially decreases and then increases. Simultaneously, the grain size gradually diminishes while element diffusion becomes more uniform. Upon reaching a critical sintering temperature (1120 °C), the original grain size disappears and carbides undergo decomposition and reprecipitation to reach an equilibrium state, with which optimal comprehensive properties can be achieved (porosity decreases to a minimum of 3.85%, grain size of 2.69 μm, Vickers hardness reaches 595 HV0.5, bending strength is at 662 MPa, coefficient of friction is at 0.74, and wear loss to 0.21 mg). These property enhancements have been attributed to reduced porosity in the composites, decreased grain size, and improved anchoring effect of carbides within the matrix. Additionally, the primary fracture mechanisms and wear mechanisms of TiC/Fe MCs with different process parameters have been analyzed. When the temperature is below 1080 °C, intergranular fracture predominates, whereas transgranular and ductile fractures become predominant above this threshold. When the temperature is below 1120 °C, fatigue wear, oxidation wear, and abrasive wear are predominantly observed. Conversely, when the temperature exceeds 1120 °C, oxidation wear and abrasive wear become the primary mechanisms.</p></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2238785424021264/pdfft?md5=17b9fe0d470706d98f374f2899ddaa23&pid=1-s2.0-S2238785424021264-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1016/j.jmrt.2024.09.146
Additive manufacturing (AM) has emerged as a pioneering method for fabricating high entropy alloys (HEAs), yet a comprehensive comparison of their nanoscale mechanical properties with those produced by the conventional casting method remains unexplored. In this study, the nanoindentation was utilized to investigate the nanoscale elastic and plastic characteristics in both additive-manufactured (AM-ed) and as-casted single-phase face-centered cubic (FCC) equiatomic CrMnFeCoNi HEAs. Herein, the hardness, reduced modulus, indentation size effect (ISE), yield strength, fracture toughness, and strain rate sensitivity were comprehensively investigated. The results indicated that the hardness of AM-ed HEA was higher than the as-casted HEA, and the reduced modulus values showed no notable distinction between the two samples. The AM-ed HEA demonstrated simultaneous enhancements in yield strength and fracture toughness compared to the as-casted HEA. The as-casted HEA possessed a more distinct indentation size effect (ISE) than the AM-ed HEA. It was observed that the AM-ed HEA exhibited relatively lower strain rate sensitivity and a larger activation volume. This direct comparison of the mechanical properties and deformation mechanisms from a nanoscale view offers unique insights for optimizing and advancing AM techniques in the fabrication of HEAs.
增材制造（AM）已成为制造高熵合金（HEAs）的一种开创性方法，但其纳米级机械性能与传统铸造方法所产生的纳米级机械性能的全面比较仍有待探索。本研究利用纳米压痕法研究了添加剂制造（AM-ed）和铸造单相面心立方（FCC）等原子铬锰铁钴镍（CrMnFeCoNi）高熵合金的纳米级弹性和塑性特征。在此，对硬度、还原模量、压痕尺寸效应（ISE）、屈服强度、断裂韧性和应变速率敏感性进行了全面研究。结果表明，AM-ed HEA 的硬度高于原铸 HEA，而还原模量值在两种样品之间没有明显差别。与原样浇铸的 HEA 相比，AM-ed HEA 同时提高了屈服强度和断裂韧性。与 AM-ed HEA 相比，原样铸造的 HEA 具有更明显的压痕尺寸效应 (ISE)。据观察，AM-ed HEA 的应变速率敏感性相对较低，活化体积较大。这种从纳米尺度直接比较机械性能和变形机制的方法为优化和推进 HEA 制造中的 AM 技术提供了独特的见解。
{"title":"A comparative study on nanoscale mechanical properties of CrMnFeCoNi high-entropy alloys fabricated by casting and additive manufacturing","authors":"","doi":"10.1016/j.jmrt.2024.09.146","DOIUrl":"10.1016/j.jmrt.2024.09.146","url":null,"abstract":"<div><p>Additive manufacturing (AM) has emerged as a pioneering method for fabricating high entropy alloys (HEAs), yet a comprehensive comparison of their nanoscale mechanical properties with those produced by the conventional casting method remains unexplored. In this study, the nanoindentation was utilized to investigate the nanoscale elastic and plastic characteristics in both additive-manufactured (AM-ed) and as-casted single-phase face-centered cubic (FCC) equiatomic CrMnFeCoNi HEAs. Herein, the hardness, reduced modulus, indentation size effect (ISE), yield strength, fracture toughness, and strain rate sensitivity were comprehensively investigated. The results indicated that the hardness of AM-ed HEA was higher than the as-casted HEA, and the reduced modulus values showed no notable distinction between the two samples. The AM-ed HEA demonstrated simultaneous enhancements in yield strength and fracture toughness compared to the as-casted HEA. The as-casted HEA possessed a more distinct indentation size effect (ISE) than the AM-ed HEA. It was observed that the AM-ed HEA exhibited relatively lower strain rate sensitivity and a larger activation volume. This direct comparison of the mechanical properties and deformation mechanisms from a nanoscale view offers unique insights for optimizing and advancing AM techniques in the fabrication of HEAs.</p></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2238785424021513/pdfft?md5=d76c39e9a1111ee92034e6047e150351&pid=1-s2.0-S2238785424021513-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1016/j.jmrt.2024.09.143
Since their advent in 2004, high-entropy alloys have allured the field of materials science and engineering. Laser cladding technology, with its advantages of a small heat-affected zone and rapid heating and cooling, has become a popular technique for preparing high-entropy alloy coatings. Traditional high-entropy alloys have the problem of strength-plasticity mismatch, which limits the further application of laser cladding high-entropy alloys in industry. As a method to solve these challenges, hard particle reinforced alloy coating technology can effectively control the comprehensive properties of high-entropy alloy coatings. This paper first explores and analyzes the five strengthening mechanisms and four main influencing factors of hard particle reinforced laser cladding alloy coatings. Then, from the perspective of introducing particle types, the research status of ceramic particles, rare earth particles and other types of hard particle reinforced laser cladding high entropy alloy coatings is introduced. Finally, the characteristics of hard particle reinforced laser cladding high-entropy alloy coatings are summarized, and future recommendations for hard particle reinforced alloy coatings technology and its application in laser cladding high-entropy alloys are proposed, which will be helpful for researchers and producers in this field.
{"title":"Review on hard particle reinforced laser cladding high-entropy alloy coatings","authors":"","doi":"10.1016/j.jmrt.2024.09.143","DOIUrl":"10.1016/j.jmrt.2024.09.143","url":null,"abstract":"<div><p>Since their advent in 2004, high-entropy alloys have allured the field of materials science and engineering. Laser cladding technology, with its advantages of a small heat-affected zone and rapid heating and cooling, has become a popular technique for preparing high-entropy alloy coatings. Traditional high-entropy alloys have the problem of strength-plasticity mismatch, which limits the further application of laser cladding high-entropy alloys in industry. As a method to solve these challenges, hard particle reinforced alloy coating technology can effectively control the comprehensive properties of high-entropy alloy coatings. This paper first explores and analyzes the five strengthening mechanisms and four main influencing factors of hard particle reinforced laser cladding alloy coatings. Then, from the perspective of introducing particle types, the research status of ceramic particles, rare earth particles and other types of hard particle reinforced laser cladding high entropy alloy coatings is introduced. Finally, the characteristics of hard particle reinforced laser cladding high-entropy alloy coatings are summarized, and future recommendations for hard particle reinforced alloy coatings technology and its application in laser cladding high-entropy alloys are proposed, which will be helpful for researchers and producers in this field.</p></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2238785424021483/pdfft?md5=0c9d7babc69b4330e6c8faa967c8428e&pid=1-s2.0-S2238785424021483-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1016/j.jmrt.2024.09.133
In this work, the resistance spot welding (RSW) process was performed to join aluminum alloy and low-alloy carbon steel plates. The macro characteristics including nugget diameters and indentation rates, microstructure and tensile-shear strength of RSW joints were investigated. The results showed that the nugget of the RSW joints comprises a ‘bowl’ shape nugget on the aluminum side and an elliptical shape nugget on the steel side. Also, the intermetallic compound (IMC) layers containing Fe4Al13 and Fe2Al5 were formed around the aluminum/steel interface with the steel side having a tongue-shape and the aluminum side having a needle-shape. According to metallurgical evaluation and temperature distribution of RSW joints analyzed by the finite element method, the nugget on the aluminum side contained the dendritic grains and equiaxed dendritic grains. The nugget on the steel side consisted of a large amount of bainite and a small amount of coarse lath martensite. The nugget diameters and the indentations rates of RSW joints increased when increasing either welding current or welding time, and decreased when increasing the electrode pressure. The maximum values of nugget diameter and indentation rate of RSW joints were 9.076 mm and 4.144% when using the welding current of 16 kA, welding time of 450 ms and electrode force of 3 kN. In tensile-shear tests, the RSW joints showed a shear-off fracture mode. When increasing the welding current, welding time or electrode force, the tensile-shear strength of RSW joints increased first, and then reached a maximum, and finally decreased. The welding current of 16 kA, the welding time of 300 ms, and the electrode pressure of 3 kN were considered as the optimal welding parameters in the present study which resulted in the maximum tensile-shear strength of 2.24 kN. In addition, the IMC layers of the RSW joints exhibited a uniform and continuous appearance with a thickness of approximately 1.9 μm, and the IMC layer in the central area was thicker than that in the edge area.
{"title":"Dissimilar joining of aluminum alloy and low-alloy carbon steel by resistance spot welding","authors":"","doi":"10.1016/j.jmrt.2024.09.133","DOIUrl":"10.1016/j.jmrt.2024.09.133","url":null,"abstract":"<div><p>In this work, the resistance spot welding (RSW) process was performed to join aluminum alloy and low-alloy carbon steel plates. The macro characteristics including nugget diameters and indentation rates, microstructure and tensile-shear strength of RSW joints were investigated. The results showed that the nugget of the RSW joints comprises a ‘bowl’ shape nugget on the aluminum side and an elliptical shape nugget on the steel side. Also, the intermetallic compound (IMC) layers containing Fe<sub>4</sub>Al<sub>13</sub> and Fe<sub>2</sub>Al<sub>5</sub> were formed around the aluminum/steel interface with the steel side having a tongue-shape and the aluminum side having a needle-shape. According to metallurgical evaluation and temperature distribution of RSW joints analyzed by the finite element method, the nugget on the aluminum side contained the dendritic grains and equiaxed dendritic grains. The nugget on the steel side consisted of a large amount of bainite and a small amount of coarse lath martensite. The nugget diameters and the indentations rates of RSW joints increased when increasing either welding current or welding time, and decreased when increasing the electrode pressure. The maximum values of nugget diameter and indentation rate of RSW joints were 9.076 mm and 4.144% when using the welding current of 16 kA, welding time of 450 ms and electrode force of 3 kN. In tensile-shear tests, the RSW joints showed a shear-off fracture mode. When increasing the welding current, welding time or electrode force, the tensile-shear strength of RSW joints increased first, and then reached a maximum, and finally decreased. The welding current of 16 kA, the welding time of 300 ms, and the electrode pressure of 3 kN were considered as the optimal welding parameters in the present study which resulted in the maximum tensile-shear strength of 2.24 kN. In addition, the IMC layers of the RSW joints exhibited a uniform and continuous appearance with a thickness of approximately 1.9 μm, and the IMC layer in the central area was thicker than that in the edge area.</p></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2238785424021380/pdfft?md5=6ef108ad2d04d3c2b04db7623239e4cd&pid=1-s2.0-S2238785424021380-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1016/j.jmrt.2024.09.145
The present study investigated the impact of 20–80 ppm Nb on the microstructure and properties of hypereutectoid pearlite steel. Remarkably, even trace amounts of Nb exhibited a favorable effect on the refinement of austenite grain. The addition of the Nb element resulted in a reduction of pearlite transition temperature, leading to a decrease of approximately 13% in lamellar spacing and 11% in the size of pearlite colonies. Furthermore, the dragging effect of the Nb element on the carbon atoms in hypereutectoid steel facilitated the control and refinement of network carbides. These findings offer valuable theoretical guidance for the production of ultra-high-strength wire rods. When the Nb content reached 80 ppm, it promoted the precipitation of (Ti, V)C, while simultaneously improving the morphology of square carbides. The grain refining strengthening mechanism accounted for about 70% of the overall strengthening effect observed in high carbon wire rods, with the influence of the Nb element primarily targeting grain refinement. Consequently, the incorporation of minute quantities of Nb presents a promising avenue for the development of ultra-high-strength hypereutectoid wire rods, offering significant potential for enhancing their strength properties.
本研究探讨了 20-80 ppm Nb 对超共晶珠光体钢微观结构和性能的影响。值得注意的是，即使是微量的铌元素也会对奥氏体晶粒的细化产生有利影响。铌元素的加入降低了珠光体转变温度，使片层间距减少了约 13%，珠光体菌落大小减少了 11%。此外，铌元素对超共析钢中碳原子的拖曳作用促进了网络碳化物的控制和细化。这些发现为生产超高强度线材提供了宝贵的理论指导。当 Nb 含量达到 80 ppm 时，它促进了 (Ti, V)C 的析出，同时改善了方形碳化物的形态。晶粒细化强化机制约占高碳线材整体强化效果的 70%，Nb 元素的影响主要针对晶粒细化。因此，掺入微量的铌元素为开发超高强度过共晶线材提供了一条前景广阔的途径，为提高线材的强度性能提供了巨大的潜力。
{"title":"Effect of trace niobium on the microstructure and properties of full-pearlite steel used in the high-strength hypereutectoid wire rods","authors":"","doi":"10.1016/j.jmrt.2024.09.145","DOIUrl":"10.1016/j.jmrt.2024.09.145","url":null,"abstract":"<div><p>The present study investigated the impact of 20–80 ppm Nb on the microstructure and properties of hypereutectoid pearlite steel. Remarkably, even trace amounts of Nb exhibited a favorable effect on the refinement of austenite grain. The addition of the Nb element resulted in a reduction of pearlite transition temperature, leading to a decrease of approximately 13% in lamellar spacing and 11% in the size of pearlite colonies. Furthermore, the dragging effect of the Nb element on the carbon atoms in hypereutectoid steel facilitated the control and refinement of network carbides. These findings offer valuable theoretical guidance for the production of ultra-high-strength wire rods. When the Nb content reached 80 ppm, it promoted the precipitation of (Ti, V)C, while simultaneously improving the morphology of square carbides. The grain refining strengthening mechanism accounted for about 70% of the overall strengthening effect observed in high carbon wire rods, with the influence of the Nb element primarily targeting grain refinement. Consequently, the incorporation of minute quantities of Nb presents a promising avenue for the development of ultra-high-strength hypereutectoid wire rods, offering significant potential for enhancing their strength properties.</p></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2238785424021501/pdfft?md5=59ecc8defec7b68b667f2e0e242ba7c5&pid=1-s2.0-S2238785424021501-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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