Materialia最新文献

β-Grain refinement in WAAM Ti-6Al-4 V processed with inter-pass ultrasonic impact peening

IF 3

Materialia Pub Date : 2024-09-15 DOI: 10.1016/j.mtla.2024.102236

{"title":"β-Grain refinement in WAAM Ti-6Al-4 V processed with inter-pass ultrasonic impact peening","authors":"","doi":"10.1016/j.mtla.2024.102236","DOIUrl":"10.1016/j.mtla.2024.102236","url":null,"abstract":"<div><p>As-deposited Wire-Arc Additive Manufactured (WAAM) Ti-6Al-4V parts typically contain large columnar β-grains on a centimetre scale, with a strong 〈001〉 fibre texture, leading to anisotropic mechanical properties and unacceptable scatter in damage tolerance. Inter-pass deformation, introduced by the application of Ultrasonic Impact Peening (UIP) across each added layer, has been shown to be effective in refining the β-grain structure and achieving a weaker texture. The depth of deformation and the grain refinement mechanism induced by UIP have been investigated by combining advanced electron backscatter diffraction (EBSD) characterization with a ‘stop action’ observation technique. UIP facilitates a similar refinement mechanism and nearly the same depth of deformation as conventional machine hammer peening, with the advantages of a much higher strain rate, lower peak force, and two orders of magnitude lower impact energy, making it a faster and more economical process. β recrystallization is seen within the deformation zone during re-heating through the α → β transition. Although new recrystallized β-grains formed in the UIP surface-deformed layer to a shallower depth than that of remelting, recrystallization initiated ahead of the melt pool and the recrystallized grains grew downwards to a greater depth before remelting. These refined grains were thus able to survive and act as nucleation sites at the fusion boundary for epitaxial regrowth during solidification, greatly refining the grain structure.</p></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142243922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Confinement effects on microstructure length scale selection in chill-cast stainless steel 冷铸不锈钢微观结构长度尺度选择的约束效应

IF 3

Materialia Pub Date : 2024-09-12 DOI: 10.1016/j.mtla.2024.102229

{"title":"Confinement effects on microstructure length scale selection in chill-cast stainless steel","authors":"","doi":"10.1016/j.mtla.2024.102229","DOIUrl":"10.1016/j.mtla.2024.102229","url":null,"abstract":"<div><p>This study reports experimental measurements of spacing selection of confined dendrite growth in chill-cast stainless steel under transient cooling conditions. This phenomenon is also explored using phase-field simulations under non-steady state cooling conditions. Two phase-field models are employed, a ternary phase-field (PF) model where Ni and Cr are explicitly simulated, and a pseudobinary model which acts as a special case. Simulations reveal a strong finite-size dependence in the primary arm spacing (PAS) of cells and dendrites. This behavior is also observed experimentally within individual grains, where dendritic fronts evolve within parent grains that impose constraints on the solidification front. Quantifying PAS by a characteristic length <span><math><msub><mrow><mi>λ</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>, this metric is observed to exhibit a stick–slip behavior as the front advances, which corresponds to times in the solidification of slow (or no) change in <span><math><msub><mrow><mi>λ</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> followed by a rapid increase in <span><math><msub><mrow><mi>λ</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> caused by a succession of cell elimination events. The statistics of cell extinction are also analyzed, finding a correlation in the statistical time between extinction events and system size. Specifically, simulations reveal that the length of time of such PAS plateaus is stochastic, exhibiting a mean time that decays approximately exponentially with system size. As system size increases, this effect diminishes and a more monotonic relation between <span><math><msub><mrow><mi>λ</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> vs. front speed is observed, consistent with classic geometric theories.</p></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589152924002266/pdfft?md5=1e0411477b227b2ab7f63ec49dbd0f3d&pid=1-s2.0-S2589152924002266-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142229079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

AC electric field-induced changes in viscosity of aqueous ceramic suspensions and tuning of freeze-cast microstructure and compressive strength

IF 3

Materialia Pub Date : 2024-09-12 DOI: 10.1016/j.mtla.2024.102232

{"title":"AC electric field-induced changes in viscosity of aqueous ceramic suspensions and tuning of freeze-cast microstructure and compressive strength","authors":"","doi":"10.1016/j.mtla.2024.102232","DOIUrl":"10.1016/j.mtla.2024.102232","url":null,"abstract":"<div><p>A systematic parametric study was conducted on alternating current (AC) electric field-assisted freeze-casting to enable a comprehensive understanding of tuning freeze-cast microstructure and compressive strength and provide insights into the role of AC field. A novel finding was that the AC field increased the viscosity of aqueous ceramic suspensions, where the viscosity increase was dependent on the ceramic loading of suspensions, dispersant concentration, and field duration. Viscosity increased with field duration for a fixed solid loading and dispersant concentration. It was suggested that AC field-induced dielectrophoretic (DEP) forces decreased interparticle distances and increased interparticle interactions in ceramic suspensions, hence viscosity. It was revealed that the increase in viscosity of ceramic suspensions due to the AC field could be reversed. It was demonstrated that simple magnetic stirring of the suspensions previously subjected to an AC field (which increased viscosity) reduced viscosity to the level of the as-prepared suspensions. For materials fabrication, an AC electric field was applied to aqueous ceramic suspensions for the desired duration, then turned OFF, followed by freeze-casting, which remarkably influenced freeze-cast sintered microstructure. The impact of the field on microstructure increased with solid loading, dispersant concentration, and field duration, and microstructure changes were associated with viscosity of suspensions prior to freeze-casting. With increasing viscosity, freeze-cast microstructure became increasingly dendritic, i.e., bridge density increased. A positive correlation was observed between bridge density and compressive strength for all the materials. Depending on the solid loading, dispersant concentration, and field duration, about 5- to 8-fold increase in strength was achieved.</p></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142243921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanical response of LPBFed TI64 thickness graded Voronoi lattice structures LPBFed TI64 厚度分级 Voronoi 网格结构的机械响应

IF 3

Materialia Pub Date : 2024-09-11 DOI: 10.1016/j.mtla.2024.102234

{"title":"Mechanical response of LPBFed TI64 thickness graded Voronoi lattice structures","authors":"","doi":"10.1016/j.mtla.2024.102234","DOIUrl":"10.1016/j.mtla.2024.102234","url":null,"abstract":"<div><p>The possibility to realize Additively Manufactured functionally graded lattice structure based on Voronoi tessellation enormously increases the possibility in tailoring the stiffness, mechanical properties and energy absorption capacity of the samples. The work presents the design and mechanical characterization of functionally thickness graded Voronoi lattice structures in comparison with constant thickness lattice structures for the evaluation of mechanical performance and energy absorption capacity. Firstly, the design and laser power bed fusion process are detailed. The dimensional deviation between designed models and Ti6Al4V specimens is quantified to assess the samples’ quality. Their mechanical performance is analyzed by quasi-static compression experimental tests, supported by numerical analysis for the evaluation of local stress distributions and deformation modes. The average dimensional deviation between CAD models and fabricated samples is 0.09 mm, likeminded with the literature optimum. The structures exhibit Young Modulus values ranging between 10 MPa and 21 MPa, compatible with biomedical applications. The compressive force for thickness graded structures tends to increase up to densification, while uniform thickness structures present an almost constant value of force in the platform stage. Additionally, the energy storage changes according to the presence of thickness gradient: the larger the thickness gradient, the larger the energy absorption capacity.</p></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S258915292400231X/pdfft?md5=492cb71c5b215d618f00acf63a8a1f9a&pid=1-s2.0-S258915292400231X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142229081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Compressive behavior of SLA open-cell lattices: A comparison between triply periodic minimal surface gyroid and stochastic structures for artificial bone SLA 开孔晶格的压缩行为：用于人工骨骼的三周期性最小表面陀螺结构与随机结构的比较

IF 3

Materialia Pub Date : 2024-09-11 DOI: 10.1016/j.mtla.2024.102233

{"title":"Compressive behavior of SLA open-cell lattices: A comparison between triply periodic minimal surface gyroid and stochastic structures for artificial bone","authors":"","doi":"10.1016/j.mtla.2024.102233","DOIUrl":"10.1016/j.mtla.2024.102233","url":null,"abstract":"<div><p>This study evaluates the compressive properties of stereolithography (SLA) fabricated open-cell lattices, specifically triply periodic minimal surface (TPMS) gyroid and stochastic structures, for artificial bone applications. Two resins, Standard White and BioMed Amber, were tested across four relative densities (0.2, 0.3, 0.4, 0.5). Mechanical characterization of horse tuber coxae trabecular bone used as a biological comparator showed an average elastic modulus of 0.05 GPa and a yield strength of 3.369 MPa. Gyroid structures exhibited higher elastic modulus and yield strengths, with BioMed Amber gyroid at a density of 0.5, achieving an elastic modulus of 0.623 GPa and yield strength of 14.149 MPa. Stochastic structures showed lower and more variable mechanical properties. The highest yield strength for stochastic structures was observed in BioMed Amber at a density of 0.5 (14.199 MPa). Comparative analysis indicated that high-performing synthetic structures approach the lower bounds of natural bone properties. Using a field-driven design approach, variable relative density structures were developed to emulate the mechanical properties of natural bone. SEM analysis provided insights into failure mechanisms, highlighting the impact of relative density on structural integrity and material ductility. This research supports the development of 3D-printed bone-like structures as viable substitutes for cadaveric specimens in preclinical tests, with implications for material science and orthopedic applications.</p></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589152924002308/pdfft?md5=b779b782de0d11c984d0433c5356e158&pid=1-s2.0-S2589152924002308-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142229080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermal behavior of coated powder during directed energy deposition (DED)

IF 3

Materialia Pub Date : 2024-09-11 DOI: 10.1016/j.mtla.2024.102235

{"title":"Thermal behavior of coated powder during directed energy deposition (DED)","authors":"","doi":"10.1016/j.mtla.2024.102235","DOIUrl":"10.1016/j.mtla.2024.102235","url":null,"abstract":"<div><p>In powder-based additive manufacturing (AM), the quality of the feedstock material is critical for obtaining enhanced mechanical properties. Recently, the application of coated powders during directed energy deposition (DED) has been prompted by the goal of fabricating composite and functional materials in-situ. The complex temperature and momentum fields established during DED render direct experimental characterization of coated powder behavior challenging. To address this challenge, this study reports on the thermal behavior of coated powders during interactions with the molten pool by constructing three-dimensional heat transfer and phase distribution models using the finite elements method (FEM). Transient temperature and phase distributions were calculated for coated and uncoated stainless steel 316L and ZnAl powders under various particle size, coating thickness, molten pool temperature, and coating material conditions. Particle residence time values were extracted from the calculations, defined as time spent by the particle before a phase change. The results show large variations in particle residence time (85 μs to 2670 μs for stainless steel 316L particles, and 48 μs to infinity for ZnAl particles) as a function of the variables considered, especially the thermal diffusivity of the coating materials, thereby highlighting the potential value of coatings as an additional design parameter in DED. Significant increases in particle residence time for both stainless steel 316L and ZnAl particles were found when contact angle increases from 0° (submergence regime) to 180° (floating regime).</p></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142243920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of multi-scale microstructural heterogeneities on the mechanical behavior of additively manufactured and post-processed Nb-based C103 alloy 多尺度微结构异质性对添加制造和后处理铌基 C103 合金力学行为的影响

IF 3

Materialia Pub Date : 2024-09-10 DOI: 10.1016/j.mtla.2024.102230

引用次数: 0

Defect evolution in pure iron under simultaneous in-situ irradiation with Fe+-He+-H2+: Impact of hydrogen & helium-dose ratios 用 Fe+-He+-H2+ 同时原位辐照纯铁时的缺陷演化：氢和氦剂量比的影响

IF 3

Materialia Pub Date : 2024-09-08 DOI: 10.1016/j.mtla.2024.102227

{"title":"Defect evolution in pure iron under simultaneous in-situ irradiation with Fe+-He+-H2+: Impact of hydrogen & helium-dose ratios","authors":"","doi":"10.1016/j.mtla.2024.102227","DOIUrl":"10.1016/j.mtla.2024.102227","url":null,"abstract":"<div><p>The properties of materials in irradiation environments are significantly influenced by hydrogen and helium. However, the effects of gas-dose ratio on the evolution of defects, which are crucial for material application assessment in various nuclear reactors and for understanding fundamental irradiation mechanisms, remain unclear. In this paper, defect evolution within pure iron was investigated in-situ through simultaneous triple-beam irradiation at 723 K using 400 keV Fe<sup>+</sup>, 50 keV He<sup>+</sup> and 50 keV H<sub>2</sub><sup>+</sup>. Four different gas-dose ratios were used: 10 appm He/dpa & 45 appm H/dpa, 10 appm He/dpa & 100 appm H/dpa, 100 appm He/dpa & 100 appm H/dpa, and 45 appm He/dpa & 10 appm H/dpa. It was observed that the gas-dose ratio significantly influenced the evolution of defects, including the size and density of dislocation loops and bubbles. It was found that an increased hydrogen-dose ratio, when paired with a constant helium-dose ratio, resulted in smaller loop sizes, but increased the density of loops and bubbles. Conversely, maintaining a constant hydrogen dose ratio while increasing the helium dose ratio proved advantageous for raising the density of loops and bubbles, and for reducing loop size. Additionally, an increase in both hydrogen and helium-dose ratios was associated with heightened swelling due to bubble formation. Moreover, hydrogen was found to have a less impact on loop nucleation compared to helium, and helium exhibited a more pronounced inhibitory effect on loop migration than hydrogen.</p></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142164473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Translucent persistent luminescence glass matrix composite obtained by pressureless viscous sintering 通过无压粘性烧结获得半透明持久发光玻璃基复合材料

IF 3

Materialia Pub Date : 2024-09-05 DOI: 10.1016/j.mtla.2024.102222

{"title":"Translucent persistent luminescence glass matrix composite obtained by pressureless viscous sintering","authors":"","doi":"10.1016/j.mtla.2024.102222","DOIUrl":"10.1016/j.mtla.2024.102222","url":null,"abstract":"<div><p>Translucent persistent luminescence glass matrix composites (PeL-GMCs) were successfully obtained for the first time using a pressureless viscous sintering method with silicate glass as the host material. Initially, persistent luminescence microparticles (PeL-MPs) of SrAl<sub>2</sub>O<sub>4</sub>: Eu<sup>2+</sup>; Dy<sup>3+</sup> were prepared by microwave-assisted synthesis under a reducing atmosphere. To obtain persistent luminescent glass matrix composites, 1 wt. % of these particles were mixed with soda-lime-silicate glass beads and pressed into pellets. Subsequently, the disk-shaped samples were heat-treated through pressureless viscous sintering. Despite some material porosity, the PeL-GMCs exhibited translucency and prolonged persistent luminescence <span><math><mrow><mo>(</mo><mrow><mo>∼</mo><mspace></mspace><mn>12</mn><mspace></mspace><mi>m</mi><mi>i</mi><mi>n</mi></mrow><mo>)</mo></mrow></math></span>. Additionally, we noted excellent compatibility between the PeL-MPs and the glass host, since no chemical interaction was found, as verified by optical microscopy, energy dispersive X-ray (EDX) mapping analysis and cathodoluminescence (CL) in SEM. Furthermore, the afterglow intensity of the particles was maintained after the preparation of materials.</p></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142173526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of sulfur impurity on the nucleation of α-Cr precipitates in nickel-based alloys 硫杂质对镍基合金中 α-Cr 沉淀成核的影响

IF 3

Materialia Pub Date : 2024-09-04 DOI: 10.1016/j.mtla.2024.102220

引用次数: 0