Pub Date : 2025-02-01DOI: 10.1016/j.matdes.2024.113572
Malaya Prasad Behera, Yifan Lv, Sarat Singamneni
Magnetism assisting the manufacturing process is well known within the energy coupled to matter realm and material processing assisting in the magnetic responses has also been in practice. The current research is an attempt to combine both approaches together in a multi-magnetic material consolidation process under the influence of external magnetic fields. Additive manufacturing by selective laser melting with controlled dispersion of multi-material magnetic powders and the application of controlled magnetic fields during material melting and consolidation are key features of the methodology. The melt-pool geometries, sub-granular structures, and the crystallographic orientations showed distinct responses with the use of external magnetic fields during laser consolidation of NdFeB and FeCo systems and their combinations with and without a third non-magnetic material matrix. As per the energy coupled to matter mechanisms and mechanics, the multi-magnetic material substrates consolidated by laser melting under external fields demonstrated patterned polar formations and predefined magnetic orientations. The directions and intensities of the north and south poles at different regions of the printed samples depend on the strengths and orientations of the external fields applied during consolidation and magnetisation fields employed after printing.
{"title":"Energy coupled to matter in additive manufacturing for controlled magnetic heterogeneity through multi-material consolidation","authors":"Malaya Prasad Behera, Yifan Lv, Sarat Singamneni","doi":"10.1016/j.matdes.2024.113572","DOIUrl":"10.1016/j.matdes.2024.113572","url":null,"abstract":"<div><div>Magnetism assisting the manufacturing process is well known within the energy coupled to matter realm and material processing assisting in the magnetic responses has also been in practice. The current research is an attempt to combine both approaches together in a multi-magnetic material consolidation process under the influence of external magnetic fields. Additive manufacturing by selective laser melting with controlled dispersion of multi-material magnetic powders and the application of controlled magnetic fields during material melting and consolidation are key features of the methodology. The melt-pool geometries, sub-granular structures, and the crystallographic orientations showed distinct responses with the use of external magnetic fields during laser consolidation of NdFeB and FeCo systems and their combinations with and without a third non-magnetic material matrix. As per the energy coupled to matter mechanisms and mechanics, the multi-magnetic material substrates consolidated by laser melting under external fields demonstrated patterned polar formations and predefined magnetic orientations. The directions and intensities of the north and south poles at different regions of the printed samples depend on the strengths and orientations of the external fields applied during consolidation and magnetisation fields employed after printing.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113572"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165642","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 : 2025-02-01DOI: 10.1016/j.matdes.2025.113585
Malachi Nelson , Shmuel Samuha , Dina Sheyfer , David Kamerman , David Yang , Kay Song , Felix Hofmann , Jon Tischler , Peter Hosemann
This work evaluates the microstructural evolution of cold-worked, stress-relieved Zircaloy-4 cladding from pristine to uniaxial and biaxial deformed states. Differential aperture Laue diffraction and electron backscatter diffraction techniques are used to characterize intragranular strains, strain gradients, and grain fragmentation as metrics of deformation microstructure. The effects of mechanical anisotropy on deformation microstructure are investigated by comparing characterization results of samples subjected to different applied loads, including biaxial internal pressure and uniaxial tension along the rolled direction at 400 °C. Quantitative comparisons are made between the pristine microstructure and deformation-induced microstructure under both loading modes. Viscoplastic self-consistent simulations are performed to further investigate the microstructural evolution. Results indicate that biaxial loading from internal pressurization increases the deformation microstructure more than uniaxial loading along the rolled direction due to the relationship between loading and texture symmetry. Additionally, characterization results and simulations show distinct deformation-induced micro-textures: axial loading promotes a prismatic fiber texture in the rolled direction, which strengthens the micro-texture inherited from pilgering, whereas pressure loading results in a texture fiber, weakening the original micro-texture inherited from pilgering.
{"title":"Deformation induced microstructure of stress relieved Zircaloy-4 cladding","authors":"Malachi Nelson , Shmuel Samuha , Dina Sheyfer , David Kamerman , David Yang , Kay Song , Felix Hofmann , Jon Tischler , Peter Hosemann","doi":"10.1016/j.matdes.2025.113585","DOIUrl":"10.1016/j.matdes.2025.113585","url":null,"abstract":"<div><div>This work evaluates the microstructural evolution of cold-worked, stress-relieved Zircaloy-4 cladding from pristine to uniaxial and biaxial deformed states. Differential aperture Laue diffraction and electron backscatter diffraction techniques are used to characterize intragranular strains, strain gradients, and grain fragmentation as metrics of deformation microstructure. The effects of mechanical anisotropy on deformation microstructure are investigated by comparing characterization results of samples subjected to different applied loads, including biaxial internal pressure and uniaxial tension along the rolled direction at 400 °C. Quantitative comparisons are made between the pristine microstructure and deformation-induced microstructure under both loading modes. Viscoplastic self-consistent simulations are performed to further investigate the microstructural evolution. Results indicate that biaxial loading from internal pressurization increases the deformation microstructure more than uniaxial loading along the rolled direction due to the relationship between loading and texture symmetry. Additionally, characterization results and simulations show distinct deformation-induced micro-textures: axial loading promotes a prismatic <span><math><mrow><mfenced><mrow><mn>10.0</mn></mrow></mfenced></mrow></math></span> fiber texture in the rolled direction, which strengthens the micro-texture inherited from pilgering, whereas pressure loading results in a <span><math><mrow><mfenced><mrow><mn>2</mn><mover><mrow><mn>1</mn></mrow><mrow><mo>¯</mo></mrow></mover><mo>.</mo><mn>0</mn></mrow></mfenced></mrow></math></span> texture fiber, weakening the original micro-texture inherited from pilgering.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113585"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165647","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 : 2025-02-01DOI: 10.1016/j.matdes.2024.113569
F.I. Azam , P.J. Tan , F. Bosi
Recent advances in small-scale fabrication enable the creation of architected metamaterials with tailored mechanical properties by manipulating their structures at the micro and nanoscale. In this study, the shape of 2D hexagonal honeycombs is modified by redistributing solid material to create stepped struts with two thicknesses. Analytical expressions are derived to show the effect of the geometric parameters on the unit cell stiffness, buckling and plastic strengths. An analytical multi-objective optimisation is performed to find the design parameters that simultaneously maximise stiffness and strength in the range of relative densities of cellular solids. Theoretical results show that a stepped strut can simultaneously enhance the stiffness of the uniform honeycomb by 36.3% and the plastic strength by 36.5%. For low relative densities, redistributing material does not significantly enhance the buckling strength of the uniform hexagonal architecture, but a stiffness gain of 29.1% is observed. Failure maps are provided to assess the influence of relative density and design parameters on the lattice failure mode. The analytical results are validated by finite element modelling and experiments, showing excellent agreement. Therefore, the study demonstrates a parametric shape optimisation approach, which can be extended to enhance the performance of other 2D and 3D mechanical metamaterials.
{"title":"Multi-objective parametric optimisation of architected hexagonal honeycomb with stepped struts","authors":"F.I. Azam , P.J. Tan , F. Bosi","doi":"10.1016/j.matdes.2024.113569","DOIUrl":"10.1016/j.matdes.2024.113569","url":null,"abstract":"<div><div>Recent advances in small-scale fabrication enable the creation of architected metamaterials with tailored mechanical properties by manipulating their structures at the micro and nanoscale. In this study, the shape of 2D hexagonal honeycombs is modified by redistributing solid material to create stepped struts with two thicknesses. Analytical expressions are derived to show the effect of the geometric parameters on the unit cell stiffness, buckling and plastic strengths. An analytical multi-objective optimisation is performed to find the design parameters that simultaneously maximise stiffness and strength in the range of relative densities of cellular solids. Theoretical results show that a stepped strut can simultaneously enhance the stiffness of the uniform honeycomb by 36.3% and the plastic strength by 36.5%. For low relative densities, redistributing material does not significantly enhance the buckling strength of the uniform hexagonal architecture, but a stiffness gain of 29.1% is observed. Failure maps are provided to assess the influence of relative density and design parameters on the lattice failure mode. The analytical results are validated by finite element modelling and experiments, showing excellent agreement. Therefore, the study demonstrates a parametric shape optimisation approach, which can be extended to enhance the performance of other 2D and 3D mechanical metamaterials.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113569"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164053","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 : 2025-02-01DOI: 10.1016/j.matdes.2025.113595
Alfred Amon , Glenn E. Bean , J.-B. Forien , Thomas Voisin , Joshua A. Hammons , Emily E. Moore , Emrah Simsek , Jibril Shittu , Katherine S. Shanks , Kelly E. Nygren , Aurélien Perron , Ryan Ott , Scott K. McCall , Hunter B. Henderson
The composition Al-16Ce-1Mg has been developed as a dedicated alloy for processing by laser powder bed fusion (LPBF). Guided by thermodynamic considerations and exploiting the unique conditions during LPBF, the strongly hypereutectic alloy features nm-scale aluminum dendrites reinforced by a continuous intermetallic network. The unique temperature stability of Al-Ce alloys as well as the microstructure topology and scale grant the alloy high strength in as-printed state with excellent thermal stability. The superior mechanical properties of the continuously reinforced nanocomposite were established by comparison with the spheroidized, microstructure of similar scale.
{"title":"Alloy design for additive manufacturing: Continuously reinforced Al-Ce nanocomposites","authors":"Alfred Amon , Glenn E. Bean , J.-B. Forien , Thomas Voisin , Joshua A. Hammons , Emily E. Moore , Emrah Simsek , Jibril Shittu , Katherine S. Shanks , Kelly E. Nygren , Aurélien Perron , Ryan Ott , Scott K. McCall , Hunter B. Henderson","doi":"10.1016/j.matdes.2025.113595","DOIUrl":"10.1016/j.matdes.2025.113595","url":null,"abstract":"<div><div>The composition Al-16Ce-1Mg has been developed as a dedicated alloy for processing by laser powder bed fusion (LPBF). Guided by thermodynamic considerations and exploiting the unique conditions during LPBF, the strongly hypereutectic alloy features nm-scale aluminum dendrites reinforced by a continuous intermetallic network. The unique temperature stability of Al-Ce alloys as well as the microstructure topology and scale grant the alloy high strength in as-printed state with excellent thermal stability. The superior mechanical properties of the continuously reinforced nanocomposite were established by comparison with the spheroidized, microstructure of similar scale.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113595"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164064","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 : 2025-02-01DOI: 10.1016/j.matdes.2025.113650
Said El Turk , Dileep Chekkaramkodi , Murad Ali , Abdulrahim A. Sajini , Haider Butt
Gold nanoparticles (Au NPs), renowned for their localized surface plasmon resonance (LSPR) based optical properties, are widely used in myriad photonics and healthcare applications. They are utilized for targeted drug delivery, biological sensing, antimicrobial systems, and for plasmonic optical devices. Here, we report an in-situ synthesis method to initiate the pre-programmed targeted incorporation of Au NPs into multi-material geometries, including 3D-printed multi-material devices and contact lenses (made from hydrogels). The existing residual Olefinic groups (C = C) present in the pHEMA hydrogels matrix were used to label the target sections for producing Au NPs. Au NPs (with LSPR wavelength near 550 nm) were discriminately formed only within the regions that were 3D printed with pHEMA hydrogels, demonstrating a new technique of selectively doping 3D geometries with nanoparticles. We demonstrate selective functionalization (with plasmonic Au NPs) of targeted regions on several centimeter-scaled 3D-printed geometries. The gold precursor solutions used do not undergo reduction and can be reused. Hence, the innovative green chemistry process is relatively fast and economical and can produce devices with multi-composite material combinations and multifunctional properties.
{"title":"Programmed polymeric integration of gold nanoparticles into multi-material 3D printed hydrogels","authors":"Said El Turk , Dileep Chekkaramkodi , Murad Ali , Abdulrahim A. Sajini , Haider Butt","doi":"10.1016/j.matdes.2025.113650","DOIUrl":"10.1016/j.matdes.2025.113650","url":null,"abstract":"<div><div>Gold nanoparticles (Au NPs), renowned for their localized surface plasmon resonance (LSPR) based optical properties, are widely used in myriad photonics and healthcare applications. They are utilized for targeted drug delivery, biological sensing, antimicrobial systems, and for plasmonic optical devices. Here, we report an in-situ synthesis method to initiate the pre-programmed targeted incorporation of Au NPs into multi-material geometries, including 3D-printed multi-material devices and contact lenses (made from hydrogels). The existing residual Olefinic groups (C = C) present in the pHEMA hydrogels matrix were used to label the target sections for producing Au NPs. Au NPs (with LSPR wavelength near 550 nm) were discriminately formed only within the regions that were 3D printed with pHEMA hydrogels, demonstrating a new technique of selectively doping 3D geometries with nanoparticles. We demonstrate selective functionalization (with plasmonic Au NPs) of targeted regions on several centimeter-scaled 3D-printed geometries. The gold precursor solutions used do not undergo reduction and can be reused. Hence, the innovative green chemistry process is relatively fast and economical and can produce devices with multi-composite material combinations and multifunctional properties.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113650"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164520","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 : 2025-02-01DOI: 10.1016/j.matdes.2025.113618
Supreeth Gaddam , Surekha Yadav , Amit Kishan Behera , Noriaki Arai , Zaynab Mahbooba , Shikhar Krishn Jha , Qiaofu Zhang , Rajiv S. Mishra
Friction stir welding (FSW) of high temperature materials such as ferrous alloys, Ti-alloys, and Ni-alloys is challenging due to the high costs, short tool lives, and limited availability of tool materials. Commercially available cermets such as WC/Co are relatively cost-effective, yet their performance is largely compromised by subpar high temperature properties of the Co binder. To address this issue, an integrated computational materials engineering (ICME) approach was applied to design a WC/HEA cermet with high entropy alloy (HEA) binder for better mechanical properties and high temperature performance. The WC/HEA cermet was fabricated by powder metallurgy route using mechanical alloying and mixing followed by spark plasma sintering (SPS). The SPS-sintered WC/HEA cermet possessed good room temperature hardness-fracture toughness synergy and hot hardness property. FSW tools were fabricated using the WC/HEA material and the tools were benchmarked against a high strength low alloy grade 50 (HSLA-50) steel. The tools performed with no observed chemical interaction with the workpiece material. The HSLA-50 material showed improved microstructure, hardness, and tensile properties post FSW. This study is the first proof-of-concept for the design, fabrication, testing, and evaluation of a novel cermet FSW tool material with low-cost and high-performance synergy for high temperature FSW application.
{"title":"Thermodynamics guided design and processing of a WC/HEA cermet tool for high temperature friction stir welding","authors":"Supreeth Gaddam , Surekha Yadav , Amit Kishan Behera , Noriaki Arai , Zaynab Mahbooba , Shikhar Krishn Jha , Qiaofu Zhang , Rajiv S. Mishra","doi":"10.1016/j.matdes.2025.113618","DOIUrl":"10.1016/j.matdes.2025.113618","url":null,"abstract":"<div><div>Friction stir welding (FSW) of high temperature materials such as ferrous alloys, Ti-alloys, and Ni-alloys is challenging due to the high costs, short tool lives, and limited availability of tool materials. Commercially available cermets such as WC/Co are relatively cost-effective, yet their performance is largely compromised by subpar high temperature properties of the Co binder. To address this issue, an integrated computational materials engineering (ICME) approach was applied to design a WC/HEA cermet with high entropy alloy (HEA) binder for better mechanical properties and high temperature performance. The WC/HEA cermet was fabricated by powder metallurgy route using mechanical alloying and mixing followed by spark plasma sintering (SPS). The SPS-sintered WC/HEA cermet possessed good room temperature hardness-fracture toughness synergy and hot hardness property. FSW tools were fabricated using the WC/HEA material and the tools were benchmarked against a high strength low alloy grade 50 (HSLA-50) steel. The tools performed with no observed chemical interaction with the workpiece material. The HSLA-50 material showed improved microstructure, hardness, and tensile properties post FSW. This study is the first proof-of-concept for the design, fabrication, testing, and evaluation of a novel cermet FSW tool material with low-cost and high-performance synergy for high temperature FSW application.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113618"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165232","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 : 2025-02-01DOI: 10.1016/j.matdes.2025.113638
Xiaoke Liu , Kejing Yu , Pengwan Chen
In this study, based on polyurethane (PU) foam material, intelligent macromolecular material “shear thickening gel (STG)” with strain rate-dependent characteristic was chosen as the reinforcing material to strengthen the PU matrix, and water together with thermal expansion microspheres (TEMs) were used as double foaming agents to prepare STG/TEMs/PU foamed composites with bimodal cell structure and excellent mechanical properties. We examined the effects of varying STG and TEMs contents on the cell structure and investigated the contributions of the matrix material and cell structure to the strain rate-dependent properties. The results demonstrate that incorporating STG into the matrix is more beneficial for enhancing the strain rate-dependent behavior of the foamed composites than altering the cell structure. Moreover, loading-unloading test analyses revealed that STG-reinforced foam and TEMs-reinforced foam exhibit distinct softening and hysteresis behaviors. This finding not only enhances our understanding of the mechanisms by which STG and TEMs operate in PU foams but also establishes a foundation for improving the performance of these materials under various extreme application conditions. Finally, we elucidated the energy dissipation mechanism of STG/TEMs/PU foam composites under multi-cycle compression loads, providing clearer insights into the microscopic changes occurring within the materials.
{"title":"From polymer matrix to cell structure: STG/TEMs/PU energy-absorbing foamed composites with strain rate-dependent and bimodal cellular structure","authors":"Xiaoke Liu , Kejing Yu , Pengwan Chen","doi":"10.1016/j.matdes.2025.113638","DOIUrl":"10.1016/j.matdes.2025.113638","url":null,"abstract":"<div><div>In this study, based on polyurethane (PU) foam material, intelligent macromolecular material “shear thickening gel (STG)” with strain rate-dependent characteristic was chosen as the reinforcing material to strengthen the PU matrix, and water together with thermal expansion microspheres (TEMs) were used as double foaming agents to prepare STG/TEMs/PU foamed composites with bimodal cell structure and excellent mechanical properties. We examined the effects of varying STG and TEMs contents on the cell structure and investigated the contributions of the matrix material and cell structure to the strain rate-dependent properties. The results demonstrate that incorporating STG into the matrix is more beneficial for enhancing the strain rate-dependent behavior of the foamed composites than altering the cell structure. Moreover, loading-unloading test analyses revealed that STG-reinforced foam and TEMs-reinforced foam exhibit distinct softening and hysteresis behaviors. This finding not only enhances our understanding of the mechanisms by which STG and TEMs operate in PU foams but also establishes a foundation for improving the performance of these materials under various extreme application conditions. Finally, we elucidated the energy dissipation mechanism of STG/TEMs/PU foam composites under multi-cycle compression loads, providing clearer insights into the microscopic changes occurring within the materials.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113638"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165321","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 : 2025-02-01DOI: 10.1016/j.matdes.2025.113641
Wei Xiao , Can Xie , Yihua Xiao , Ke Tang , Zhangbo Wang , Dean Hu , Ruqi Ding , Zhongdong Jiao
Vacuum-powered actuators possess inherent security, reliability, and durability compared with positive-pressure-powered actuators. However, achieving the variable curvatures of such actuators with a single input is challenging and has rarely been reported so far. Herein, we develop a new vacuum-powered soft bending actuator (VPSBA) that can bend clockwise and anti-clockwise by tuning the interior angle of the chambers. The experimental results show that the actuator can yield a maximum bending angle of 127.7° and 171.5° for the interior angle of 76° and 104°, respectively. The finite element results show a great agreement with the experiment results. The maximum relative error between the FEM results and experiment results is about 8.8%. And we find that the maximum bending angle is affected by the geometrical parameters but actuating pressures. The actuating pressure and thickness of the front and back walls significantly affect the bending curvature. Consequently, a biarc approximation method, surrogate model, and multi-objective particle swarm algorithm are employed to realize the programmable variable curvatures of the VPSBA by tuning the actuating pressure and thickness of the front and back walls. We design successfully three VPSBAs whose deformation can accurately match arc and cosine curves with a single input.
{"title":"A new vacuum-powered soft bending actuator with programmable variable curvatures","authors":"Wei Xiao , Can Xie , Yihua Xiao , Ke Tang , Zhangbo Wang , Dean Hu , Ruqi Ding , Zhongdong Jiao","doi":"10.1016/j.matdes.2025.113641","DOIUrl":"10.1016/j.matdes.2025.113641","url":null,"abstract":"<div><div>Vacuum-powered actuators possess inherent security, reliability, and durability compared with positive-pressure-powered actuators. However, achieving the variable curvatures of such actuators with a single input is challenging and has rarely been reported so far. Herein, we develop a new vacuum-powered soft bending actuator (VPSBA) that can bend clockwise and anti-clockwise by tuning the interior angle of the chambers. The experimental results show that the actuator can yield a maximum bending angle of 127.7° and 171.5° for the interior angle of 76° and 104°, respectively. The finite element results show a great agreement with the experiment results. The maximum relative error between the FEM results and experiment results is about 8.8%. And we find that the maximum bending angle is affected by the geometrical parameters but actuating pressures. The actuating pressure and thickness of the front and back walls significantly affect the bending curvature. Consequently, a biarc approximation method, surrogate model, and multi-objective particle swarm algorithm are employed to realize the programmable variable curvatures of the VPSBA by tuning the actuating pressure and thickness of the front and back walls. We design successfully three VPSBAs whose deformation can accurately match arc and cosine curves with a single input.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113641"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165325","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 : 2025-02-01DOI: 10.1016/j.matdes.2025.113584
Chun Hu , Stanislav Mráz , Peter J. Pöllmann , T. Wojcik , M. Podsednik , B. Hajas , A. Limbeck , Nikola Koutná , Jochen M. Schneider , Paul H. Mayrhofer
Despite AlB2 is the most typical structure prototype of transition metal diborides (TMB2), studies on AlB2 thin films are scarce. Furthermore, although Al is the primary alloying element for TMB2 to improve their oxidation resistance, no such data are available for AlB2 thin films. Here, we develop AlBx thin films through non-reactive magnetron sputtering of an AlB2 compound target and investigate their microstructure, mechanical properties, thermal stability and oxidation resistance. Keeping the substrate temperature at 700 °C and increasing the Ar pressure during deposition from pAr = 0.4 to 0.8 to 1.2, Pa, the films‘ chemistry slightly varies between x = 1.99, 1.97, and to 2.27, respectively. Detailed transmission electron microscopy shows that the highly (0001)-oriented AlB2.27 thin film exhibits small platelet-like amorphous B regions next to the large columnar α-structured AlB2 crystals. In the as deposited state, this film exhibits an indentation hardness and elastic modulus of 19.2 ± 1.2 GPa and 331.8 ± 14.4 GPa, respectively. Between 850 and 900 °C, the AlB2.27 thin film starts to decompose into tetragonal (t-) AlB12, but still maintains dominant α structure up to 950 °C. At 1000 °C, the thin film is completely decomposed into t-AlB12 and hexagonal AlB10. The AlB2.27 thin film also shows exceptional oxidation-resistance with an onset temperature for the formation of oxides (α-Al2O3 and o-Al18B4O33) between 950 and 1000 °C when exposed to lab-air.
{"title":"Microstructure, mechanical properties, thermal decomposition and oxidation sequences of crystalline AlB2 thin films","authors":"Chun Hu , Stanislav Mráz , Peter J. Pöllmann , T. Wojcik , M. Podsednik , B. Hajas , A. Limbeck , Nikola Koutná , Jochen M. Schneider , Paul H. Mayrhofer","doi":"10.1016/j.matdes.2025.113584","DOIUrl":"10.1016/j.matdes.2025.113584","url":null,"abstract":"<div><div>Despite AlB<sub>2</sub> is the most typical structure prototype of transition metal diborides (TMB<sub>2</sub>), studies on AlB<sub>2</sub> thin films are scarce. Furthermore, although Al is the primary alloying element for TMB<sub>2</sub> to improve their oxidation resistance, no such data are available for AlB<sub>2</sub> thin films. Here, we develop AlB<sub>x</sub> thin films through non-reactive magnetron sputtering of an AlB<sub>2</sub> compound target and investigate their microstructure, mechanical properties, thermal stability and oxidation resistance. Keeping the substrate temperature at 700 °C and increasing the Ar pressure during deposition from <em>p</em><sub>Ar</sub> = 0.4 to 0.8 to 1.2, Pa, the films‘ chemistry slightly varies between x = 1.99, 1.97, and to 2.27, respectively. Detailed transmission electron microscopy shows that the highly (0001)-oriented AlB<sub>2.27</sub> thin film exhibits small platelet-like amorphous B regions next to the large columnar α-structured AlB<sub>2</sub> crystals. In the as deposited state, this film exhibits an indentation hardness and elastic modulus of 19.2 ± 1.2 GPa and 331.8 ± 14.4 GPa, respectively. Between 850 and 900 °C, the AlB<sub>2.27</sub> thin film starts to decompose into tetragonal (t-) AlB<sub>12</sub>, but still maintains dominant α structure up to 950 °C. At 1000 °C, the thin film is completely decomposed into t-AlB<sub>12</sub> and hexagonal AlB<sub>10</sub>. The AlB<sub>2.27</sub> thin film also shows exceptional oxidation-resistance with an onset temperature for the formation of oxides (α-Al<sub>2</sub>O<sub>3</sub> and o-Al<sub>18</sub>B<sub>4</sub>O<sub>33</sub>) between 950 and 1000 °C when exposed to lab-air.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113584"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164051","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 : 2025-02-01DOI: 10.1016/j.matdes.2025.113621
Aleksandra Królicka , José Antonio Jimenez , Francisca G. Caballero
The comparative analysis of two ways to achieve ultra-fine bainitic steels considering isothermal heat treatment above and below martensite start (Ms) temperature was formulated. Although the presence of pre-martensite below the Ms temperature accelerates the nucleation time of the bainitic transformation, the time to finish the transformation is longer (∼11.5 h) compared to the treatment above Ms (∼5 h). A qualitative and quantitative analysis of the morphology of the bainitic structure demonstrated that there are no significant differences in the thickness of the bainitic ferrite laths in both cases. However, a clear refinement of the retained austenite blocks of the steel treated below Ms was observed. Moreover, TEM and STEM/EDS studies revealed precipitation processes associated with the decomposition of the metastable bainitic and bainitic-martensitic structures during the tempering. It was shown that both heat treatment routes lead to secondary hardening during the tempering at 550 °C. At lower tempering temperatures, the bainitic matrix obtained above Ms was characterized by higher thermal stability, while the presence of pre-martensite in the steel treated below Ms has greater effectiveness in the secondary hardening effect at higher tempering temperatures and therefore in thermal stability of bainite at the high-temperature tempering range. These results provide a new perspective for designing heat treatment processes for advanced bainitic steels in applications subjected to operation at elevated temperatures.
{"title":"Pre-martensite and bainite reactions: A thermal stability study","authors":"Aleksandra Królicka , José Antonio Jimenez , Francisca G. Caballero","doi":"10.1016/j.matdes.2025.113621","DOIUrl":"10.1016/j.matdes.2025.113621","url":null,"abstract":"<div><div>The comparative analysis of two ways to achieve ultra-fine bainitic steels considering isothermal heat treatment above and below martensite start (M<sub>s</sub>) temperature was formulated. Although the presence of pre-martensite below the M<sub>s</sub> temperature accelerates the nucleation time of the bainitic transformation, the time to finish the transformation is longer (∼11.5 h) compared to the treatment above M<sub>s</sub> (∼5 h). A qualitative and quantitative analysis of the morphology of the bainitic structure demonstrated that there are no significant differences in the thickness of the bainitic ferrite laths in both cases. However, a clear refinement of the retained austenite blocks of the steel treated below M<sub>s</sub> was observed. Moreover, TEM and STEM/EDS studies revealed precipitation processes associated with the decomposition of the metastable bainitic and bainitic-martensitic structures during the tempering. It was shown that both heat treatment routes lead to secondary hardening during the tempering at 550 °C. At lower tempering temperatures, the bainitic matrix obtained above M<sub>s</sub> was characterized by higher thermal stability, while the presence of pre-martensite in the steel treated below M<sub>s</sub> has greater effectiveness in the secondary hardening effect at higher tempering temperatures and therefore in thermal stability of bainite at the high-temperature tempering range. These results provide a new perspective for designing heat treatment processes for advanced bainitic steels in applications subjected to operation at elevated temperatures.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"250 ","pages":"Article 113621"},"PeriodicalIF":7.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164517","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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