This study investigates the microstructure and mechanical properties of non-equimolar CoCrFeMoNi high-entropy alloy (HEA) and SUS310S stainless steel dissimilar welds using different filler materials. The dissimilar welding was performed on gas tungsten arc welding with Inconel 82, Inconel 625, and 316L stainless steel fillers. The non-equimolar CoCrFeMoNi HEA is shown effective weldability with these fillers, maintaining distinguished phase stability and structural integrity. Microstructural analysis revealed varied grain morphologies influenced by the heat in the fusion zone and heat-affected zone. Mechanical properties were evaluated through tensile and hardness tests, showing that welds with Inconel 625 filler exhibited superior strength and ductility. The weld hardness value was maintained at 170 HV, with a yield strength of 301 MPa and an ultimate tensile strength of 587 MPa, resulting in a joint efficiency of 106 %.
{"title":"Investigate on dissimilar welding of high-entropy alloy and 310S with various fillers","authors":"Chihhsien Liao , Tingen Shen , Weichen Hsu , Hsiencheng Wu , Chenchou Chung , Chunlung Peng , Chewei Tsai","doi":"10.1016/j.matdes.2024.113454","DOIUrl":"10.1016/j.matdes.2024.113454","url":null,"abstract":"<div><div>This study investigates the microstructure and mechanical properties of non-equimolar CoCrFeMoNi high-entropy alloy (HEA) and SUS310S stainless steel dissimilar welds using different filler materials. The dissimilar welding was performed on gas tungsten arc welding with Inconel 82, Inconel 625, and 316L stainless steel fillers. The non-equimolar CoCrFeMoNi HEA is shown effective weldability with these fillers, maintaining distinguished phase stability and structural integrity. Microstructural analysis revealed varied grain morphologies influenced by the heat in the fusion zone and heat-affected zone. Mechanical properties were evaluated through tensile and hardness tests, showing that welds with Inconel 625 filler exhibited superior strength and ductility. The weld hardness value was maintained at 170 HV, with a yield strength of 301 MPa and an ultimate tensile strength of 587 MPa, resulting in a joint efficiency of 106 %.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"248 ","pages":"Article 113454"},"PeriodicalIF":7.6,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.matdes.2024.113442
Ziao Yan , Shicheng Liu , Zhanpeng Sun , Kangshuo Li , Nan Su , Guang Yang
Balling is the main surface defect in additive manufacturing, leading to surface roughness and uneven powder deposition. Through the in-situ X-ray imaging technology, the melting process of high layer thickness 316L powder under different process parameters was investigated in real time in this work. We systematically elaborate the complex formation mechanism of balling at high layer thickness, and the key mechanism underlies the splatter’s coalescence during the flight and solidification stages. The frequent spatters coalescence dominates the large-size balling. The spatter coalescence event was roughly quantified, and the coalescence rate ranges from 42.42 % to 73.04 %. The swing of the irregular balls and jumping of the regular small balls were observed, and the solidification time ranges from 10 ms to 20 ms. Moreover, the detailed morphological parameters including the contact angle and counts of the spatter were clarified, and the algebraic equations about the contact angle and the volumetric energy density were established. This study provides a systematical understanding of the balling phenomenon during laser powder bed fusion of 316L at high layer thickness.
球化是增材制造中的主要表面缺陷，会导致表面粗糙和粉末沉积不均匀。本研究通过原位 X 射线成像技术，实时研究了不同工艺参数下高层厚 316L 粉末的熔化过程。我们系统地阐述了高层厚时复杂的成球机理，以及飞溅物在飞行和凝固阶段凝聚的关键机理。频繁的飞溅凝聚主导了大尺寸成球。对飞溅凝聚事件进行了粗略量化，其凝聚率介于 42.42 % 到 73.04 % 之间。观察到不规则球的摆动和规则小球的跳跃，凝固时间范围为 10 ms 至 20 ms。此外，还明确了包括接触角和飞溅计数在内的详细形态参数，并建立了接触角和体积能量密度的代数方程。这项研究系统地了解了 316L 在高层厚激光粉末床熔化过程中的成球现象。
{"title":"In situ X-ray imaging and quantitative analysis of balling during laser powder bed fusion of 316L at high layer thickness","authors":"Ziao Yan , Shicheng Liu , Zhanpeng Sun , Kangshuo Li , Nan Su , Guang Yang","doi":"10.1016/j.matdes.2024.113442","DOIUrl":"10.1016/j.matdes.2024.113442","url":null,"abstract":"<div><div>Balling is the main surface defect in additive manufacturing, leading to surface roughness and uneven powder deposition. Through the in-situ X-ray imaging technology, the melting process of high layer thickness 316L powder under different process parameters was investigated in real time in this work. We systematically elaborate the complex formation mechanism of balling at high layer thickness, and the key mechanism underlies the splatter’s coalescence during the flight and solidification stages. The frequent spatters coalescence dominates the large-size balling. The spatter coalescence event was roughly quantified, and the coalescence rate ranges from 42.42 % to 73.04 %. The swing of the irregular balls and jumping of the regular small balls were observed, and the solidification time ranges from 10 ms to 20 ms. Moreover, the detailed morphological parameters including the contact angle and counts of the spatter were clarified, and the algebraic equations about the contact angle and the volumetric energy density were established. This study provides a systematical understanding of the balling phenomenon during laser powder bed fusion of 316L at high layer thickness.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"248 ","pages":"Article 113442"},"PeriodicalIF":7.6,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655039","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}
Understanding the melting and sintering behavior of composite metal nanoparticles is of great significance to promote the synthesis and application of nanomaterials. In this work, molecular dynamics simulation method was employed to examine in detail the influence of sintering temperature, particle size and Fe content on the melting and sintering behavior of Cu-Fe mixed nanoparticles. The results show that the melting point of Cu-Fe mixed nanoparticles exhibits a strong size dependence and gradually increases with the increase in Fe content. High sintering temperatures significantly promotes the sintering process and the degree of atomic migration, and the diffusion behavior on the surface is enhanced, providing a significant driving force for sintering. Since smaller particle sizes have higher surface energy, the relationship between the neck parameters during the sintering process of different particle sizes is 4 nm > 6 nm > 8 nm, and the displacement of surface atoms is always greater than that of internal atoms. As the Fe content increases, the sintering of nanoparticles and the migration of atoms decrease, leading to a lower degree of sintering. This study further provides an atomic-scale theoretical basis for the melting and sintering behavior of Cu-Fe mixed nanoparticles.
{"title":"Study on the melting and sintering behavior of Cu-Fe mixed nanoparticles based on molecular dynamics simulations","authors":"Cheng Zhang , Wenfei Peng , Yiyu Shao , Moliar Oleksandr , Longhui Lu , Xiaohui Zhang","doi":"10.1016/j.matdes.2024.113457","DOIUrl":"10.1016/j.matdes.2024.113457","url":null,"abstract":"<div><div>Understanding the melting and sintering behavior of composite metal nanoparticles is of great significance to promote the synthesis and application of nanomaterials. In this work, molecular dynamics simulation method was employed to examine in detail the influence of sintering temperature, particle size and Fe content on the melting and sintering behavior of Cu-Fe mixed nanoparticles. The results show that the melting point of Cu-Fe mixed nanoparticles exhibits a strong size dependence and gradually increases with the increase in Fe content. High sintering temperatures significantly promotes the sintering process and the degree of atomic migration, and the diffusion behavior on the surface is enhanced, providing a significant driving force for sintering. Since smaller particle sizes have higher surface energy, the relationship between the neck parameters during the sintering process of different particle sizes is 4 nm > 6 nm > 8 nm, and the displacement of surface atoms is always greater than that of internal atoms. As the Fe content increases, the sintering of nanoparticles and the migration of atoms decrease, leading to a lower degree of sintering. This study further provides an atomic-scale theoretical basis for the melting and sintering behavior of Cu-Fe mixed nanoparticles.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"248 ","pages":"Article 113457"},"PeriodicalIF":7.6,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.matdes.2024.113450
Liang Xu , Jie Zhang , Jiang Li , Huaan Tian , Chaofan Zheng , Shaoyun Guo
Viscoelastic damping materials (VDMs) are valued for their high damping characteristics in vibration and noise control. However, they typically underperform at lower frequencies and add substantial mass to structures. This study introduces an innovative approach by embedding an acoustic black hole (ABH) structure within VDMs (ABH-VDM) to achieve lightweight and broadband vibration damping. Firstly, a finite element method-based vibration model is developed to analyse the propagation and attenuation characteristics of vibrations in a plate strip embedded with ABH-VDM. This analysis provides insights into the dynamic behaviour and damping effectiveness of the proposed structure. Secondly, the study investigates the vibration reduction capabilities and mass implications of ABH-VDM on large-scale plate structures. The influence of ABH structural parameters, including the power exponent, cut-off thickness, and array configuration, is systematically investigated to optimize damping performance. Finally, experimental validation confirms that ABH-VDM achieves an additional 1.4 dB reduction in vibration across the entire frequency spectrum, with a bandwidth extension of 900 Hz. Moreover, ABH-VDM reduces mass by 8.6 %, demonstrating its potential for lightweight vibration control in structural applications. This research contributes valuable insights into advancing lightweight and broadband damping solutions for enhanced vibration management in engineering systems.
{"title":"Design of a lightweight broadband vibration reduction structure with embedded acoustic black holes in viscoelastic damping materials","authors":"Liang Xu , Jie Zhang , Jiang Li , Huaan Tian , Chaofan Zheng , Shaoyun Guo","doi":"10.1016/j.matdes.2024.113450","DOIUrl":"10.1016/j.matdes.2024.113450","url":null,"abstract":"<div><div>Viscoelastic damping materials (VDMs) are valued for their high damping characteristics in vibration and noise control. However, they typically underperform at lower frequencies and add substantial mass to structures. This study introduces an innovative approach by embedding an acoustic black hole (ABH) structure within VDMs (ABH-VDM) to achieve lightweight and broadband vibration damping. Firstly, a finite element method-based vibration model is developed to analyse the propagation and attenuation characteristics of vibrations in a plate strip embedded with ABH-VDM. This analysis provides insights into the dynamic behaviour and damping effectiveness of the proposed structure. Secondly, the study investigates the vibration reduction capabilities and mass implications of ABH-VDM on large-scale plate structures. The influence of ABH structural parameters, including the power exponent, cut-off thickness, and array configuration, is systematically investigated to optimize damping performance. Finally, experimental validation confirms that ABH-VDM achieves an additional 1.4 dB reduction in vibration across the entire frequency spectrum, with a bandwidth extension of 900 Hz. Moreover, ABH-VDM reduces mass by 8.6 %, demonstrating its potential for lightweight vibration control in structural applications. This research contributes valuable insights into advancing lightweight and broadband damping solutions for enhanced vibration management in engineering systems.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"248 ","pages":"Article 113450"},"PeriodicalIF":7.6,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-10DOI: 10.1016/j.matdes.2024.113448
Chun Chen , Xiang Wang , Hua Huang , Jialin Niu , Jian-Feng Nie , Guangyin Yuan
In this study, the age-hardening response and microstructural evolution of an as-extruded biodegradable Zn-1.5Cu-1.5Ag (wt.%) alloy during ageing at 25 ℃, 100 ℃, 150 ℃ and 200 ℃ are studied. The age-hardening response is generally weak, and the largest hardness increment is observed after ageing at 150 ℃ for 24 hours. Discontinuous precipitation (DP) and continuous precipitation (CP) occur competitively during ageing at 150 ℃ or 200 ℃, while only DP is observed during ageing at 25 ℃ or 100 ℃. All the precipitates formed through DP and CP are identified as ε-(Ag, Cu)Zn4 that has a hexagonal structure. Analysis of possible strengthening mechanisms shows that grain boundary strengthening and precipitation hardening contribute to the major part of yield strength in the as-extruded condition. Ageing treatments generate a limited increment in yield strength due to the small difference between the hardness of ε-(Ag, Cu)Zn4 and the Zn matrix and the reduced solid solution strengthening effect. Artificial ageing at 150 ℃ for 48 hours effectively improves the stability of the mechanical properties of the as-extruded Zn-1.5Cu-1.5Ag alloy. This process fully depletes the excessive solutes in the supersaturated Zn matrix, ensuring that the alloy maintains consistent mechanical properties when stored at room temperature.
{"title":"Ageing response and microstructural evolution of biodegradable Zn-1.5Cu-1.5Ag alloy","authors":"Chun Chen , Xiang Wang , Hua Huang , Jialin Niu , Jian-Feng Nie , Guangyin Yuan","doi":"10.1016/j.matdes.2024.113448","DOIUrl":"10.1016/j.matdes.2024.113448","url":null,"abstract":"<div><div>In this study, the age-hardening response and microstructural evolution of an as-extruded biodegradable Zn-1.5Cu-1.5Ag (wt.%) alloy during ageing at 25 ℃, 100 ℃, 150 ℃ and 200 ℃ are studied. The age-hardening response is generally weak, and the largest hardness increment is observed after ageing at 150 ℃ for 24 hours. Discontinuous precipitation (DP) and continuous precipitation (CP) occur competitively during ageing at 150 ℃ or 200 ℃, while only DP is observed during ageing at 25 ℃ or 100 ℃. All the precipitates formed through DP and CP are identified as <em>ε</em>-(Ag, Cu)Zn<sub>4</sub> that has a hexagonal structure. Analysis of possible strengthening mechanisms shows that grain boundary strengthening and precipitation hardening contribute to the major part of yield strength in the as-extruded condition. Ageing treatments generate a limited increment in yield strength due to the small difference between the hardness of <em>ε</em>-(Ag, Cu)Zn<sub>4</sub> and the Zn matrix and the reduced solid solution strengthening effect. Artificial ageing at 150 ℃ for 48 hours effectively improves the stability of the mechanical properties of the as-extruded Zn-1.5Cu-1.5Ag alloy. This process fully depletes the excessive solutes in the supersaturated Zn matrix, ensuring that the alloy maintains consistent mechanical properties when stored at room temperature.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"248 ","pages":"Article 113448"},"PeriodicalIF":7.6,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-09DOI: 10.1016/j.matdes.2024.113449
Bin Zhu , Nathanael Leung , Brandon Steel , David England , Yinglong He , Andrew J. London , Hannah Zhang , Michael Gorley , Yiqiang Wang , Mark J. Whiting , Tan Sui
Fusion In-vessel components, assembled and maintained using laser welding, one of the most promising techniques, exhibit complex distributions of residual stress, microstructures, and material properties. These residual stresses can compromise structural integrity and lifespan of critical components. Although using advanced experimental measurements can evaluate the residual stress for individual case, extending the measurements to massive number of components are costly and time-consuming. Traditional machine learning (ML) models struggle to account for the heterogeneity and anisotropy of these stress distributions. Here, we develop a novel ML framework based on the Eurofer97 steel, the structural material for in-vessel components. The ML framework is trained on high-resolution residual stress data derived from recently-developed evaluation techniques. Combining with microstructures, the model enables prediction of heterogenous and anisotropic residual stress distribution. It successfully predicts the compressive residual stress in fusion zone (∼−200 MPa) balanced by tensile residual stress in heat affected zone (∼300 MPa), aligning closely with experimental results with the R-squared value of 0.989 and the mean square error of 10−4. Unlike experiments that take hours, the ML model provides predictions within seconds. It offers valuable insights into residual stress prediction for various joints, enhancing the reliability and lifetime prediction of in-vessel components.
激光焊接是最有前途的技术之一，使用激光焊接组装和维护的舱内部件会表现出复杂的残余应力分布、微观结构和材料特性。这些残余应力会影响关键部件的结构完整性和使用寿命。虽然使用先进的实验测量方法可以评估单个部件的残余应力，但将测量方法扩展到大量部件则既费钱又费时。传统的机器学习（ML）模型很难解释这些应力分布的异质性和各向异性。在此，我们开发了一种基于 Eurofer97 钢（用于舱内组件的结构材料）的新型 ML 框架。该 ML 框架是通过最近开发的评估技术获得的高分辨率残余应力数据进行训练的。结合微观结构，该模型可以预测异质和各向异性的残余应力分布。它成功地预测了熔合区的压缩残余应力（∼-200 兆帕）和热影响区的拉伸残余应力（∼300 兆帕），与实验结果非常吻合，R 平方值为 0.989，均方误差为 10-4。与耗时数小时的实验不同，ML 模型可在几秒钟内完成预测。它为各种接头的残余应力预测提供了宝贵的见解，提高了容器内部件的可靠性和寿命预测。
{"title":"Machine learning powered predictive modelling of complex residual stress for nuclear fusion reactor design","authors":"Bin Zhu , Nathanael Leung , Brandon Steel , David England , Yinglong He , Andrew J. London , Hannah Zhang , Michael Gorley , Yiqiang Wang , Mark J. Whiting , Tan Sui","doi":"10.1016/j.matdes.2024.113449","DOIUrl":"10.1016/j.matdes.2024.113449","url":null,"abstract":"<div><div>Fusion In-vessel components, assembled and maintained using laser welding, one of the most promising techniques, exhibit complex distributions of residual stress, microstructures, and material properties. These residual stresses can compromise structural integrity and lifespan of critical components. Although using advanced experimental measurements can evaluate the residual stress for individual case, extending the measurements to massive number of components are costly and time-consuming. Traditional machine learning (ML) models struggle to account for the heterogeneity and anisotropy of these stress distributions. Here, we develop a novel ML framework based on the Eurofer97 steel, the structural material for in-vessel components. The ML framework is trained on high-resolution residual stress data derived from recently-developed evaluation techniques. Combining with microstructures, the model enables prediction of heterogenous and anisotropic residual stress distribution. It successfully predicts the compressive residual stress in fusion zone (∼−200 MPa) balanced by tensile residual stress in heat affected zone (∼300 MPa), aligning closely with experimental results with the <em>R</em>-squared value of 0.989 and the mean square error of 10<sup>−4</sup>. Unlike experiments that take hours, the ML model provides predictions within seconds. It offers valuable insights into residual stress prediction for various joints, enhancing the reliability and lifetime prediction of in-vessel components.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"248 ","pages":"Article 113449"},"PeriodicalIF":7.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.matdes.2024.113410
Cai Lu , Bozhao Wu , Yangyang Pan , Hui Fang , Jianxin Liu , Xiaoqi Yang , Ze Liu
We report a general flash arc synthesis (FAS) method to batch fabricate alloy micro/nanocrystals of up to eight components on a wafer-scale. Combined with experiments and first-principle calculations, we show that the shape and size distribution of prepared micro/nanocrystals is determined by both the adhesion energy and diffusion coefficient of metal atoms on the highly oriented pyrolytic graphite (HOPG) substrate. Moreover, we show that surface atomic steps in the HOPG substrate can induce self-assembly and anchoring of metal micro/nanocrystals. The proposed method can essentially prepare alloy micro/nanocrystals with any number of components due to the high cooling rate of micro/nanocrystals, which could lead to the quick development of new materials by directly alloying on the nanoscale and facilitate the applications of alloy micro/nanocrystals.
{"title":"Alloying at the nanoscale","authors":"Cai Lu , Bozhao Wu , Yangyang Pan , Hui Fang , Jianxin Liu , Xiaoqi Yang , Ze Liu","doi":"10.1016/j.matdes.2024.113410","DOIUrl":"10.1016/j.matdes.2024.113410","url":null,"abstract":"<div><div>We report a general flash arc synthesis (FAS) method to batch fabricate alloy micro/nanocrystals of up to eight components on a wafer-scale. Combined with experiments and first-principle calculations, we show that the shape and size distribution of prepared micro/nanocrystals is determined by both the adhesion energy and diffusion coefficient of metal atoms on the highly oriented pyrolytic graphite (HOPG) substrate. Moreover, we show that surface atomic steps in the HOPG substrate can induce self-assembly and anchoring of metal micro/nanocrystals. The proposed method can essentially prepare alloy micro/nanocrystals with any number of components due to the high cooling rate of micro/nanocrystals, which could lead to the quick development of new materials by directly alloying on the nanoscale and facilitate the applications of alloy micro/nanocrystals.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"247 ","pages":"Article 113410"},"PeriodicalIF":7.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.matdes.2024.113438
Douglas Wagner , Matteo Bernardi , Felix Grassel , Ting Chen , Kai Schimanski , Luciano Bergmann , Benjamin Klusemann
This study investigates the application of Friction Stir Welding (FSW) for fabricating stiffened structures in AA2219-T31 using a T-lap configuration. These structures are vital in various applications where weight is a crucial factor, including aircraft fuselages, railway cars and automotive parts. This study assesses the formation dynamics of lack of bonding in single-pass welds, including the examination of microstructure, hardness, mechanical properties, and fracture locations. A second welding pass was employed over the initial weld to eliminate the lack of bonding. The implementation of a second welding pass significantly improves joint efficiency, achieving up to 90 % of the ultimate tensile strength in the skin direction and 95 % in the stiffener direction, establishing a new benchmark for AA2219-T31 T-joints. Additionally, no significant differences in grain size were found between single- and double-pass welds, highlighting the lack of bonding as key factor affecting the strength of the joints. The proposed method offers valuable insights for future industrial applications to avoid defects such as lack of bonding.
本研究探讨了如何应用搅拌摩擦焊（FSW）在 AA2219-T31 中使用 T 型搭接结构制造加劲结构。这些结构在飞机机身、铁路车辆和汽车零件等重量是关键因素的各种应用中至关重要。本研究评估了单道焊接中缺乏结合的形成动态，包括检查微观结构、硬度、机械性能和断裂位置。在第一道焊缝上采用了第二道焊缝，以消除结合力不足现象。第二道焊缝的实施大大提高了接头效率，在表皮方向达到了极限抗拉强度的 90%，在加强筋方向达到了极限抗拉强度的 95%，为 AA2219-T31 T 型接头确立了新的基准。此外，单道焊缝和双道焊缝之间的晶粒大小没有明显差异，这表明缺乏粘接是影响接头强度的关键因素。所提出的方法为未来的工业应用提供了宝贵的见解，以避免出现粘接不足等缺陷。
{"title":"Analysis of mechanical properties and microstructure of single and double-pass friction stir welded T-joints for aluminium stiffened panels","authors":"Douglas Wagner , Matteo Bernardi , Felix Grassel , Ting Chen , Kai Schimanski , Luciano Bergmann , Benjamin Klusemann","doi":"10.1016/j.matdes.2024.113438","DOIUrl":"10.1016/j.matdes.2024.113438","url":null,"abstract":"<div><div>This study investigates the application of Friction Stir Welding (FSW) for fabricating stiffened structures in AA2219-T31 using a T-lap configuration. These structures are vital in various applications where weight is a crucial factor, including aircraft fuselages, railway cars and automotive parts. This study assesses the formation dynamics of lack of bonding in single-pass welds, including the examination of microstructure, hardness, mechanical properties, and fracture locations. A second welding pass was employed over the initial weld to eliminate the lack of bonding. The implementation of a second welding pass significantly improves joint efficiency, achieving up to 90 % of the ultimate tensile strength in the skin direction and 95 % in the stiffener direction, establishing a new benchmark for AA2219-T31 T-joints. Additionally, no significant differences in grain size were found between single- and double-pass welds, highlighting the lack of bonding as key factor affecting the strength of the joints. The proposed method offers valuable insights for future industrial applications to avoid defects such as lack of bonding.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"247 ","pages":"Article 113438"},"PeriodicalIF":7.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.matdes.2024.113411
M. Gathmann , D. Moisi , H. Springer
Size, morphology and distribution of light and stiff, but inherently brittle particles are of critical importance for the property profile of high modulus steels. Powder atomisation can dramatically reduce the borides’ size to the nanoscale, but they typically coarsen substantially during annealing or compaction via hot isostatic pressing. This study investigated the effect of compaction parameters, namely temperature, pressure and time on the coarsening mechanism, porosity evolution and resultant mechanical properties of atomised Fe-Cr-B powder. Increasing annealing temperature and time from 950 to 1150 °C, respectively, 30 min to 8 h, resulted in a non-linear boride radius growth from 76 nm in the atomised state to 1.9 µm. Hot isostatic pressing, with additional pressures up to 140 MPa, decreased the pore size from about 5 to 0.2 µm. An optimised hot isostatic pressing processing window was defined at 1050 °C and 140 MPa, combining sufficiently reduced defects with a limited particle radius, and yielded in 730 MPa tensile strength at more than 20 % tensile elongation. Powder-metallurgical synthesis of Fe-Cr-B achieved similar properties to casted and hot-rolled material, by avoiding component size scaling effects of casting. The underlying phenomena and optimisation of high modulus steel production via powder metallurgy are discussed.
{"title":"Coarsening mechanism of M2B-borides and their effect on the mechanical properties of high modulus steels","authors":"M. Gathmann , D. Moisi , H. Springer","doi":"10.1016/j.matdes.2024.113411","DOIUrl":"10.1016/j.matdes.2024.113411","url":null,"abstract":"<div><div>Size, morphology and distribution of light and stiff, but inherently brittle particles are of critical importance for the property profile of high modulus steels. Powder atomisation can dramatically reduce the borides’ size to the nanoscale, but they typically coarsen substantially during annealing or compaction via hot isostatic pressing. This study investigated the effect of compaction parameters, namely temperature, pressure and time on the coarsening mechanism, porosity evolution and resultant mechanical properties of atomised Fe-Cr-B powder. Increasing annealing temperature and time from 950 to 1150 °C, respectively, 30 min to 8 h, resulted in a non-linear boride radius growth from 76 nm in the atomised state to 1.9 µm. Hot isostatic pressing, with additional pressures up to 140 MPa, decreased the pore size from about 5 to 0.2 µm. An optimised hot isostatic pressing processing window was defined at 1050 °C and 140 MPa, combining sufficiently reduced defects with a limited particle radius, and yielded in 730 MPa tensile strength at more than 20 % tensile elongation. Powder-metallurgical synthesis of Fe-Cr-B achieved similar properties to casted and hot-rolled material, by avoiding component size scaling effects of casting. The underlying phenomena and optimisation of high modulus steel production via powder metallurgy are discussed.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"247 ","pages":"Article 113411"},"PeriodicalIF":7.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.matdes.2024.113412
Sebastian Stammkötter , Jochen Tenkamp , Mirko Teschke , Kai Donnerbauer , Alexander Koch , Timo Platt , Dirk Biermann , Frank Walther
Al-Si alloys are commonly used in the automotive and aircraft industry because of their excellent strength-to-weight ratio. Due to the laser powder bed fusion manufacturing process, inhomogeneous cooling affects the microstructure as well as defect distributions. Within this paper, the uniform fatigue damage tolerance assessment was further qualified for (miniature) bending specimens with different loaded volumes based on the concepts according to Murakami (√area) and Shiozawa for an initial defect-based model. These approaches were used to calculate defect-related fatigue life curves, in which the cyclic stress intensity factor (ΔK) at the initiating defect (√area) was used to represent local stress concentration at the crack tip instead of nominal stress-based S-N curves. Results of S-N curves did not allow a precise lifetime prediction due to increasing effect of manufacturing-related defect distributions, while fracture mechanical approaches enable a uniform fatigue lifetime description of different testing volumes. The calculated fatigue limit and short crack threshold value suggested by Noguchi based on the extended approach of Murakami need to be compared and validated experimentally. Furthermore, the effects of miniaturization and crack propagation have been identified and considered. Uniform fatigue life predictions and efficient materials testing have been combined and show potential for future research.
{"title":"Fatigue and short crack assessment of powder bed fusion laser-based fabricated AlSi10Mg miniature specimens under alternating bending load","authors":"Sebastian Stammkötter , Jochen Tenkamp , Mirko Teschke , Kai Donnerbauer , Alexander Koch , Timo Platt , Dirk Biermann , Frank Walther","doi":"10.1016/j.matdes.2024.113412","DOIUrl":"10.1016/j.matdes.2024.113412","url":null,"abstract":"<div><div>Al-Si alloys are commonly used in the automotive and aircraft industry because of their excellent strength-to-weight ratio. Due to the laser powder bed fusion manufacturing process, inhomogeneous cooling affects the microstructure as well as defect distributions. Within this paper, the uniform fatigue damage tolerance assessment was further qualified for (miniature) bending specimens with different loaded volumes based on the concepts according to Murakami (√area) and Shiozawa for an initial defect-based model. These approaches were used to calculate defect-related fatigue life curves, in which the cyclic stress intensity factor (Δ<em>K</em>) at the initiating defect (√area) was used to represent local stress concentration at the crack tip instead of nominal stress-based S-N curves. Results of S-N curves did not allow a precise lifetime prediction due to increasing effect of manufacturing-related defect distributions, while fracture mechanical approaches enable a uniform fatigue lifetime description of different testing volumes. The calculated fatigue limit and short crack threshold value suggested by Noguchi based on the extended approach of Murakami need to be compared and validated experimentally. Furthermore, the effects of miniaturization and crack propagation have been identified and considered. Uniform fatigue life predictions and efficient materials testing have been combined and show potential for future research.</div></div>","PeriodicalId":383,"journal":{"name":"Materials & Design","volume":"247 ","pages":"Article 113412"},"PeriodicalIF":7.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651858","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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