Pub Date : 2025-03-22DOI: 10.1016/j.matdes.2025.113858
Indira Dey , Raphael Floeder , Karsten Kunze , Christian Roth , Konrad Wegener
This study investigates laser welding of additively (AM) and conventionally manufactured (CM) parts, aiming to enhance cost and energy efficiency for a diverse product range. In this context, hybrid specimens combining AM/CM subparts were produced, where AM subparts were created using DED, CM parts by hot forming, and the two were joined using laser welding. The material analysed is soft martensitic stainless steel. Mechanical characterisation was performed through tensile testing and hardness measurements and microstructure characterisation through EBSD, SEM, EDS, and light microscopy. The study reveals the presence of ultra-fine grains in the heat treated laser weld segments which suggests grain subdivision due to martensite deformation. As built hybrid specimens exhibited lower toughness due to the laser welds and lower strength due to the CM segments. The weakest point after the heat treatment was the HAZ of the CM segment. The best mechanical performance was observed in homogeneously heat-treated AM specimens. Moreover, the variability in grain size were examined but did not conform grain boundary strengthening, particularly after the heat treatment. This study highlights the critical influence of microstructural variations on the mechanical properties of hybrid welds, emphasizing the need for further investigation into strengthening mechanisms and individual heat treatments.
{"title":"Mechanical properties and microstructure analysis of laser welded hybrid parts made of additively and conventionally manufactured 1.4313 soft martensitic steel","authors":"Indira Dey , Raphael Floeder , Karsten Kunze , Christian Roth , Konrad Wegener","doi":"10.1016/j.matdes.2025.113858","DOIUrl":"10.1016/j.matdes.2025.113858","url":null,"abstract":"<div><div>This study investigates laser welding of additively (AM) and conventionally manufactured (CM) parts, aiming to enhance cost and energy efficiency for a diverse product range. In this context, hybrid specimens combining AM/CM subparts were produced, where AM subparts were created using DED, CM parts by hot forming, and the two were joined using laser welding. The material analysed is soft martensitic stainless steel. Mechanical characterisation was performed through tensile testing and hardness measurements and microstructure characterisation through EBSD, SEM, EDS, and light microscopy. The study reveals the presence of ultra-fine grains in the heat treated laser weld segments which suggests grain subdivision due to martensite deformation. As built hybrid specimens exhibited lower toughness due to the laser welds and lower strength due to the CM segments. The weakest point after the heat treatment was the HAZ of the CM segment. The best mechanical performance was observed in homogeneously heat-treated AM specimens. Moreover, the variability in grain size were examined but did not conform grain boundary strengthening, particularly after the heat treatment. This study highlights the critical influence of microstructural variations on the mechanical properties of hybrid welds, emphasizing the need for further investigation into strengthening mechanisms and individual heat treatments.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113858"},"PeriodicalIF":7.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705764","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 : 2025-03-22DOI: 10.1016/j.matdes.2025.113871
Shunrong Chen , Chunyue Zhao , Wei Wang , Songyuan Yang , Chengjiang Zhou
This paper proposes a convolutional neural network (CNN)-assisted method for both forward optimization and inverse design of terahertz metamaterial sensors (TMSs), addressing the limitations imposed by reliance on manual trial-and-error processes. A hollow n-shaped TMS based on copper foil was developed, exhibiting two distinct resonance peaks between 0.3 and 1.4 THz. The formation mechanisms of resonance peaks were analyzed based on electric field and current distribution, while the sensing performance of the TMS was investigated. In the forward optimization stage, the n-shaped unit of TMS was converted into a data matrix, and the CNN was developed to predict the resonance frequency. In the inverse design stage, a predictive model for estimating the size of the TMS was developed by applying one-dimensional convolution to the transmission coefficients. The training dataset employed for forward optimization and inverse design achieved coefficients of determination (R2) of 0.99 and 0.99, respectively, with corresponding mean absolute error (MAE) values of 3.90 and 1.04. The efficacy of the proposed method was validated through terahertz time-domain spectroscopy (THz-TDS) measurements of TMS. Experimental assessments were conducted on glucose solutions of varying concentrations to ascertain the sensing capabilities. The proposed method contributes to the efficient design and optimization of TMS.
{"title":"Convolutional neural network-assisted design and validation of terahertz metamaterial sensor","authors":"Shunrong Chen , Chunyue Zhao , Wei Wang , Songyuan Yang , Chengjiang Zhou","doi":"10.1016/j.matdes.2025.113871","DOIUrl":"10.1016/j.matdes.2025.113871","url":null,"abstract":"<div><div>This paper proposes a convolutional neural network (CNN)-assisted method for both forward optimization and inverse design of terahertz metamaterial sensors (TMSs), addressing the limitations imposed by reliance on manual trial-and-error processes. A hollow n-shaped TMS based on copper foil was developed, exhibiting two distinct resonance peaks between 0.3 and 1.4 THz. The formation mechanisms of resonance peaks were analyzed based on electric field and current distribution, while the sensing performance of the TMS was investigated. In the forward optimization stage, the n-shaped unit of TMS was converted into a data matrix, and the CNN was developed to predict the resonance frequency. In the inverse design stage, a predictive model for estimating the size of the TMS was developed by applying one-dimensional convolution to the transmission coefficients. The training dataset employed for forward optimization and inverse design achieved coefficients of determination (R<sup>2</sup>) of 0.99 and 0.99, respectively, with corresponding mean absolute error (MAE) values of 3.90 and 1.04. The efficacy of the proposed method was validated through terahertz time-domain spectroscopy (THz-TDS) measurements of TMS. Experimental assessments were conducted on glucose solutions of varying concentrations to ascertain the sensing capabilities. The proposed method contributes to the efficient design and optimization of TMS.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113871"},"PeriodicalIF":7.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724434","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}
To develop a highly wear-resistant coating with self-lubricating characteristics, this study reports the use of laser cladding to fabricate WC/MoS2 composite coatings on the surface of 65Mn steel plates. Here, we investigated the effects of different laser powers and MoS2 contents on the phase composition, phase distribution, microstructure, and friction/wear properties of the coatings, focusing on heat and element competition mechanisms, as well as the wear mechanism of the Ni-based WC/MoS2 composite coatings. The results show that compared with MoS2, WC remains disadvantaged in terms of heat competition in the molten pool. However, during MoS2 thermal decomposition, the free Cr atoms in the pool are also captured, not only changing the type and morphology of the MxCy carbides and inhibiting WC heat damage but also resulting in a decreased content of MxCy carbides within the coating. When a significant amount of CrxSy gathers on the coating surface, a stable and continuous lubricating film is formed, allowing the coating to balance the wear resistance with lubrication.
{"title":"Laser cladding Ni-based WC/MoS2 composite coatings: Particle competition mechanism and tribological performance","authors":"Kepeng Huang , Changjiang Zheng , Zexi Chen, Dayou Wu, Xuemei Yi","doi":"10.1016/j.matdes.2025.113868","DOIUrl":"10.1016/j.matdes.2025.113868","url":null,"abstract":"<div><div>To develop a highly wear-resistant coating with self-lubricating characteristics, this study reports the use of laser cladding to fabricate WC/MoS<sub>2</sub> composite coatings on the surface of 65Mn steel plates. Here, we investigated the effects of different laser powers and MoS<sub>2</sub> contents on the phase composition, phase distribution, microstructure, and friction/wear properties of the coatings, focusing on heat and element competition mechanisms, as well as the wear mechanism of the Ni-based WC/MoS<sub>2</sub> composite coatings. The results show that compared with MoS<sub>2</sub>, WC remains disadvantaged in terms of heat competition in the molten pool. However, during MoS<sub>2</sub> thermal decomposition, the free Cr atoms in the pool are also captured, not only changing the type and morphology of the M<sub>x</sub>C<sub>y</sub> carbides and inhibiting WC heat damage but also resulting in a decreased content of M<sub>x</sub>C<sub>y</sub> carbides within the coating. When a significant amount of Cr<sub>x</sub>S<sub>y</sub> gathers on the coating surface, a stable and continuous lubricating film is formed, allowing the coating to balance the wear resistance with lubrication.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113868"},"PeriodicalIF":7.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684509","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 : 2025-03-22DOI: 10.1016/j.matdes.2025.113870
Wang Chen , Pengfei Shen , Wei Li , Shuailing Ma , Min Lian , Xinmiao Wei , Yaqian Dan , Xingbin Zhao , Mengyao Qi , Tian Cui , Ralf Riedel
Dense and fine-grained high entropy transition metal carbides are considered as one of the most promising materials with superior hardness, fracture toughness and electrical conductivity. However, the difficulty in preparing high-quality fine-grained samples limits their wide applications. In this work, fully dense and fine-grained (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C ceramics were prepared by high temperature and high pressure technique. Ultra-high pressure significantly accelerates the densification process and significantly lowers the sintering temperature due to the pressure-induced grain fusion and grain growth suppression effect. The monolith sintered at 1200 ℃ and 15 GPa exhibits a Vickers hardness of 27.9 GPa (9.8 N), and a high fracture toughness of 8.9 MPa·m1/2, both of which are the highest values for the reported high-entropy carbide ceramics. Advanced characterization demonstrates that high hardness and toughness are closely related to the high dislocation density, fine grain size, and the high relative density. Additionally, the sintering temperature is significantly reduced by applying pressure, which provides a general route for preparing advanced polycrystalline high-entropy carbide ceramics for more superior mechanical properties.
{"title":"Pressure-driven grain fusion and mechanical properties improvement of high-entropy (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C ceramics","authors":"Wang Chen , Pengfei Shen , Wei Li , Shuailing Ma , Min Lian , Xinmiao Wei , Yaqian Dan , Xingbin Zhao , Mengyao Qi , Tian Cui , Ralf Riedel","doi":"10.1016/j.matdes.2025.113870","DOIUrl":"10.1016/j.matdes.2025.113870","url":null,"abstract":"<div><div>Dense and fine-grained high entropy transition metal carbides are considered as one of the most promising materials with superior hardness, fracture toughness and electrical conductivity. However, the difficulty in preparing high-quality fine-grained samples limits their wide applications. In this work, fully dense and fine-grained (Ti<sub>0.2</sub>Zr<sub>0.2</sub>Nb<sub>0.2</sub>Hf<sub>0.2</sub>Ta<sub>0.2</sub>)C ceramics were prepared by high temperature and high pressure technique. Ultra-high pressure significantly accelerates the densification process and significantly lowers the sintering temperature due to the pressure-induced grain fusion and grain growth suppression effect. The monolith sintered at 1200 ℃ and 15 GPa exhibits a Vickers hardness of 27.9 GPa (9.8 N), and a high fracture toughness of 8.9 MPa·m<sup>1/2</sup>, both of which are the highest values for the reported high-entropy carbide ceramics. Advanced characterization demonstrates that high hardness and toughness are closely related to the high dislocation density, fine grain size, and the high relative density. Additionally, the sintering temperature is significantly reduced by applying pressure, which provides a general route for preparing advanced polycrystalline high-entropy carbide ceramics for more superior mechanical properties.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113870"},"PeriodicalIF":7.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705767","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 : 2025-03-21DOI: 10.1016/j.matdes.2025.113865
Boburjon Mukhamedov, Ferenc Tasnádi, Igor A. Abrikosov
Machine learning-augmented first-principles simulations facilitate the exploration of alloying and thermal treatments for tailoring material properties in industrial applications. However, addressing challenges near dynamical instabilities requires rigorous validation of machine-learned interatomic potentials (MLIP) to ensure their reliable applicability. In this study we have trained MLIP using moment tensor potentials to simulate finite temperature elastic properties of multicomponent β-Ti94-xNbxZr6 alloys. Our simulations predict the presence of the elinvar effect for the wide range of temperatures. Importantly, we predict that in a vicinity of dynamical and mechanical instability, the β-Ti94-xNbxZr6 alloys demonstrate strongly non-linear concentration-dependence of elastic moduli, which leads to low values of moduli comparable to that of human bone. Moreover, these alloys demonstrate a strong anisotropy of directional Young’s modulus which can be helpful for microstructure tailoring and design of materials with desired elastic properties.
{"title":"Machine learning interatomic potential for the low-modulus Ti-Nb-Zr alloys in the vicinity of dynamical instability","authors":"Boburjon Mukhamedov, Ferenc Tasnádi, Igor A. Abrikosov","doi":"10.1016/j.matdes.2025.113865","DOIUrl":"10.1016/j.matdes.2025.113865","url":null,"abstract":"<div><div>Machine learning-augmented first-principles simulations facilitate the exploration of alloying and thermal treatments for tailoring material properties in industrial applications. However, addressing challenges near dynamical instabilities requires rigorous validation of machine-learned interatomic potentials (MLIP) to ensure their reliable applicability. In this study we have trained MLIP using moment tensor potentials to simulate finite temperature elastic properties of multicomponent β-Ti<sub>94-x</sub>Nb<sub>x</sub>Zr<sub>6</sub> alloys. Our simulations predict the presence of the elinvar effect for the wide range of temperatures. Importantly, we predict that in a vicinity of dynamical and mechanical instability, the β-Ti<sub>94-x</sub>Nb<sub>x</sub>Zr<sub>6</sub> alloys demonstrate strongly non-linear concentration-dependence of elastic moduli, which leads to low values of moduli comparable to that of human bone. Moreover, these alloys demonstrate a strong anisotropy of directional Young’s modulus which can be helpful for microstructure tailoring and design of materials with desired elastic properties.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113865"},"PeriodicalIF":7.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716279","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 : 2025-03-21DOI: 10.1016/j.matdes.2025.113863
Yanbin Chen , Qi Liu , Wei Zhang , Cheng Jin
In this paper, a new type of spoof surface plasmon polaritons (SSPPs) is proposed to construct lowpass filters based on grounded coplanar waveguide (GCPW) transmission lines. Compared with the conventional SSPP-based lowpass filters, the proposed lowpass filters using GCPW-based SSPPs only need two transition unit cells to achieve mode conversion from GCPW to SSPPs, which significantly reduce the circuit size. In addition, the cutoff frequency of the filter can be independently controlled by modifying the corresponding structural parameters. In order to further decrease the cutoff frequency of the lowpass filter, another improved SSPP structure is constructed by periodically adding L-shaped grooves on the SSPP unit cells. The experimental results show that the measurement results are in good agreement with the simulation results, which validate the correctness of the proposed structures and design method.
{"title":"Compact lowpass filters using GCPW-based spoof surface plasmon polaritons","authors":"Yanbin Chen , Qi Liu , Wei Zhang , Cheng Jin","doi":"10.1016/j.matdes.2025.113863","DOIUrl":"10.1016/j.matdes.2025.113863","url":null,"abstract":"<div><div>In this paper, a new type of spoof surface plasmon polaritons (SSPPs) is proposed to construct lowpass filters based on grounded coplanar waveguide (GCPW) transmission lines. Compared with the conventional SSPP-based lowpass filters, the proposed lowpass filters using GCPW-based SSPPs only need two transition unit cells to achieve mode conversion from GCPW to SSPPs, which significantly reduce the circuit size. In addition, the cutoff frequency of the filter can be independently controlled by modifying the corresponding structural parameters. In order to further decrease the cutoff frequency of the lowpass filter, another improved SSPP structure is constructed by periodically adding L-shaped grooves on the SSPP unit cells. The experimental results show that the measurement results are in good agreement with the simulation results, which validate the correctness of the proposed structures and design method.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113863"},"PeriodicalIF":7.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143759883","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 : 2025-03-21DOI: 10.1016/j.matdes.2025.113860
Yaqing Feng , Pengyuan Wang , Chenghao Wu
Patients with hemiplegia, neurologic injuries, and sports trauma require muscle strength rehabilitation training, the existing rigid equipment is uncomfortable and bulky, and wearable training devices are not suitable for the whole-stage of passive, assistant, active and resistance rehabilitation training, and are difficult to provide comprehensive and real-time feedback on the current rehabilitation level. This paper proposes a multi-layer cylindric soft actuator with axial tensile stiffness variation, and pneumatic control is utilized to achieve axial elongation and resistance adjustment. The resistance is changed through the stick–slip friction of soft structure during tooth structures engagement and sliding, and the tensile stiffness of the soft actuator can be changed by 7.2 times with air pressure increased by only 20 kPa. Capacitive strain sensing is used to obtain elongation and stiffness feedback, and the closed-loop control errors for axial elongation and stiffness variation are only 2.02 % and 1.20 %, respectively. Finally, an application of elbow joint rehabilitation training demonstrates that the proposed variable stiffness actuator is feasible for whole-stage training and providing feedback on joint angle amplitude and strength.
{"title":"Variable tensile stiffness pneumatic actuators with adjustable stick-slip friction of soft-tooth structures","authors":"Yaqing Feng , Pengyuan Wang , Chenghao Wu","doi":"10.1016/j.matdes.2025.113860","DOIUrl":"10.1016/j.matdes.2025.113860","url":null,"abstract":"<div><div>Patients with hemiplegia, neurologic injuries, and sports trauma require muscle strength rehabilitation training, the existing rigid equipment is uncomfortable and bulky, and wearable training devices are not suitable for the whole-stage of passive, assistant, active and resistance rehabilitation training, and are difficult to provide comprehensive and real-time feedback on the current rehabilitation level. This paper proposes a multi-layer cylindric soft actuator with axial tensile stiffness variation, and pneumatic control is utilized to achieve axial elongation and resistance adjustment. The resistance is changed through the stick–slip friction of soft structure during tooth structures engagement and sliding, and the tensile stiffness of the soft actuator can be changed by 7.2 times with air pressure increased by only 20 kPa. Capacitive strain sensing is used to obtain elongation and stiffness feedback, and the closed-loop control errors for axial elongation and stiffness variation are only 2.02 % and 1.20 %, respectively. Finally, an application of elbow joint rehabilitation training demonstrates that the proposed variable stiffness actuator is feasible for whole-stage training and providing feedback on joint angle amplitude and strength.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113860"},"PeriodicalIF":7.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683973","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 : 2025-03-21DOI: 10.1016/j.matdes.2025.113845
S. Hoerl , C. Micheletti , S. Amini , E. Griesshaber , K.-U. Hess , A.G. Checa , M. Peharda , W.W. Schmahl
Bivalves populate various marine environments and follow diverse lifestyles: attaching to substrates, burrowing into sediments or swimming in water. Their shells play a crucial role in the survival of organisms as they shield the soft tissue from external attacks and facilitate their respective lifestyles. Valve movement is controlled by one or two adductor muscles and the hinge. While the function and structure of adductor muscles can vary, the shell-muscle attachment develops the myostracum, a unique microstructural design. Sectioned parallel and perpendicular to the inner shell surface, we investigated myostracal and non-myostracal microstructures, textures and nanomechanical properties for three bivalve species: The burrowing Glycymeris pilosa, the sessile Chama arcana and the swimming Placopecten magellanicus.
Analyses were conducted using electron backscatter diffraction measurements, laser confocal and backscatter electron imaging, nanoindentation testing and thermogravimetric analysis. We find that the myostracal microstructure is generated mainly through physical determinants, regardless of the bivalve lifestyle and adductor muscle structure. If aragonitic, we show that adjacent shell layers are used as templates for the formation of the myostracal microstructure and highlight how bivalves use the adjacent crystal arrangement to predetermine myostracal microstructure up to inner shell surfaces. Furthermore, this study demonstrates how myostracal layers exceed the hardness of the non-myostracal valves and that of geological aragonite, irrespective of grain size and morphology. Due to the anisotropy of aragonite, we show that aragonite c-axis orientation notably affects the hardness of crystals. The highest hardness is measured when indentation is normal to the shell surface in aragonite c-axes direction.
{"title":"Correlation between nanomechanical properties and microstructural design concepts of bivalve muscle attachment sites","authors":"S. Hoerl , C. Micheletti , S. Amini , E. Griesshaber , K.-U. Hess , A.G. Checa , M. Peharda , W.W. Schmahl","doi":"10.1016/j.matdes.2025.113845","DOIUrl":"10.1016/j.matdes.2025.113845","url":null,"abstract":"<div><div>Bivalves populate various marine environments and follow diverse lifestyles: attaching to substrates, burrowing into sediments or swimming in water. Their shells play a crucial role in the survival of organisms as they shield the soft tissue from external attacks and facilitate their respective lifestyles. Valve movement is controlled by one or two adductor muscles and the hinge. While the function and structure of adductor muscles can vary, the shell-muscle attachment develops the myostracum, a unique microstructural design. Sectioned parallel and perpendicular to the inner shell surface, we investigated myostracal and non-myostracal microstructures, textures and nanomechanical properties for three bivalve species: The burrowing <em>Glycymeris pilosa</em>, the sessile <em>Chama arcana</em> and the swimming <em>Placopecten magellanicus</em>.</div><div>Analyses were conducted using electron backscatter diffraction measurements, laser confocal and backscatter electron imaging, nanoindentation testing and thermogravimetric analysis. We find that the myostracal microstructure is generated mainly through physical determinants, regardless of the bivalve lifestyle and adductor muscle structure. If aragonitic, we show that adjacent shell layers are used as templates for the formation of the myostracal microstructure and highlight how bivalves use the adjacent crystal arrangement to predetermine myostracal microstructure up to inner shell surfaces. Furthermore, this study demonstrates how myostracal layers exceed the hardness of the non-myostracal valves and that of geological aragonite, irrespective of grain size and morphology. Due to the anisotropy of aragonite, we show that aragonite c-axis orientation notably affects the hardness of crystals. The highest hardness is measured when indentation is normal to the shell surface in aragonite c-axes direction.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113845"},"PeriodicalIF":7.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143697962","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 : 2025-03-21DOI: 10.1016/j.matdes.2025.113852
Xueying Guan , Elke Deckers , Hao Dong , Maarten Hornikx , Jieun Yang
The acoustic absorption of a porous structure within a specific frequency range can be tuned by varying its porosity along its thickness. In this work, triply periodic minimal surfaces (TPMS) are employed to generate graded porous structures, where the continuous porosity gradient is controlled by a mathematical function involving geometric parameters. A hybrid homogenization technique, combined with the transfer matrix method (TMM), is used to predict the normal incidence absorption coefficient of the graded TPMS structure. The porosity distribution along the thickness is then optimized using a global search method combined with a local gradient-based solver to maximize acoustic absorption within a target frequency range. The optimization results suggest that a combination of high- and low-porosity layers achieves broadband impedance matching conditions by shifting the so-called quarter-wavelength resonance frequencies. The design of the TPMS absorbers is validated through impedance tube measurements of 3D-printed samples.
{"title":"Optimization of graded porous acoustic absorbers based on triply periodic minimal surfaces","authors":"Xueying Guan , Elke Deckers , Hao Dong , Maarten Hornikx , Jieun Yang","doi":"10.1016/j.matdes.2025.113852","DOIUrl":"10.1016/j.matdes.2025.113852","url":null,"abstract":"<div><div>The acoustic absorption of a porous structure within a specific frequency range can be tuned by varying its porosity along its thickness. In this work, triply periodic minimal surfaces (TPMS) are employed to generate graded porous structures, where the continuous porosity gradient is controlled by a mathematical function involving geometric parameters. A hybrid homogenization technique, combined with the transfer matrix method (TMM), is used to predict the normal incidence absorption coefficient of the graded TPMS structure. The porosity distribution along the thickness is then optimized using a global search method combined with a local gradient-based solver to maximize acoustic absorption within a target frequency range. The optimization results suggest that a combination of high- and low-porosity layers achieves broadband impedance matching conditions by shifting the so-called quarter-wavelength resonance frequencies. The design of the TPMS absorbers is validated through impedance tube measurements of 3D-printed samples.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113852"},"PeriodicalIF":7.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683972","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 : 2025-03-21DOI: 10.1016/j.matdes.2025.113859
Yihu Zang , Jilin Xie , Yuhua Chen , Min Zheng , Xiaofang Liu , Jiajia Shen , J.P. Oliveira
Despite the popularity of joining NiTi and Ti6Al4V in aerospace and biomedical applications, effective solutions for their dissimilar joining are limited due to brittle intermetallic compounds. In this work, we successfully joined NiTi/Ti6Al4V using resistance spot welding. Results indicate that the number of cracks is the primary factor determining the lap-shear load. The extensive accumulation of brittle Ti2Ni at the bottom of the weld pool leads to stress concentration and is the main cause of crack initiation. X-ray diffraction and phase diagrams revealed the solidification sequence of liquid metal in the joint, including , , . Electron backscatter diffraction analysis showed that weld nugget grains exhibited random orientation, with stress concentration mainly within the Ti2Ni phase on the Ti6Al4V side and at the boundary between the NiTi and Ti2Ni phases, contributing to high susceptibility to deformation and cracking in these regions. Nanoindentation analysis further demonstrated that the welding process diminished the superelastic performance of NiTi, attributable to Ti2Ni phase, grain coarsening and the orientation deviation of B2 NiTi.
{"title":"Resistance spot welded NiTi shape memory alloy to Ti6Al4V: Correlation between joint microstructure, cracking and mechanical properties","authors":"Yihu Zang , Jilin Xie , Yuhua Chen , Min Zheng , Xiaofang Liu , Jiajia Shen , J.P. Oliveira","doi":"10.1016/j.matdes.2025.113859","DOIUrl":"10.1016/j.matdes.2025.113859","url":null,"abstract":"<div><div>Despite the popularity of joining NiTi and Ti6Al4V in aerospace and biomedical applications, effective solutions for their dissimilar joining are limited due to brittle intermetallic compounds. In this work, we successfully joined NiTi/Ti6Al4V using resistance spot welding. Results indicate that the number of cracks is the primary factor determining the lap-shear load. The extensive accumulation of brittle Ti<sub>2</sub>Ni at the bottom of the weld pool leads to stress concentration and is the main cause of crack initiation. X-ray diffraction and phase diagrams revealed the solidification sequence of liquid metal in the joint, including <span><math><mrow><mi>L</mi><mo>→</mo><mi>N</mi><mi>i</mi><mi>T</mi><mi>i</mi></mrow></math></span>, <span><math><mrow><mi>L</mi><mo>+</mo><mi>N</mi><mi>i</mi><mi>T</mi><mi>i</mi><mo>→</mo><msub><mrow><mi>Ti</mi></mrow><mn>2</mn></msub><mi>N</mi><mi>i</mi></mrow></math></span>, <span><math><mrow><mi>L</mi><mo>→</mo><mi>β</mi><mi>T</mi><mi>i</mi><mo>+</mo><msub><mrow><mi>Ti</mi></mrow><mn>2</mn></msub><mi>N</mi><mi>i</mi></mrow></math></span>. Electron backscatter diffraction analysis showed that weld nugget grains exhibited random orientation, with stress concentration mainly within the Ti<sub>2</sub>Ni phase on the Ti6Al4V side and at the boundary between the NiTi and Ti<sub>2</sub>Ni phases, contributing to high susceptibility to deformation and cracking in these regions. Nanoindentation analysis further demonstrated that the welding process diminished the superelastic performance of NiTi, attributable to Ti<sub>2</sub>Ni phase, grain coarsening and the orientation deviation of B2 NiTi.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"253 ","pages":"Article 113859"},"PeriodicalIF":7.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684519","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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