Pub Date : 2024-10-01DOI: 10.1016/j.mfglet.2024.09.033
Guan-Cheng Chen , Xiaochun Li
In the realm of high-performance applications, wrought aluminum alloys are esteemed for their high mechanical properties and excellent strength-to-weight ratio. However, their limited castability poses challenges in economically producing intricate structures through casting processes. To address this issue, a small proportion of TiC nanoparticles is introduced into the melts of AA 2024 and AA 6063 for nano-treating. This nano-treatment imparts several beneficial effects, including the delayed release of latent heat, inhibition of grain growth, and improvement of wettability. These effects enhance the fluidity of the melt, eliminate hot cracking, and elevate the surface quality of the castings. The outcomes underscore the promising potential of emerging nano-treatment technology in rendering traditionally non-castable wrought aluminum alloys suitable for cost-effective casting processes, ultimately delivering high-performance products for a wide range of applications.
在高性能应用领域，锻造铝合金因其高机械性能和出色的强度重量比而备受推崇。然而，其有限的可铸造性给通过铸造工艺经济地生产复杂结构带来了挑战。为解决这一问题，在 AA 2024 和 AA 6063 的熔体中引入了少量 TiC 纳米颗粒进行纳米处理。这种纳米处理具有多种有益效果，包括延迟潜热释放、抑制晶粒生长和改善润湿性。这些效果增强了熔体的流动性，消除了热裂纹，并提高了铸件的表面质量。这些成果凸显了新兴纳米处理技术在使传统上不可铸造的锻造铝合金适用于具有成本效益的铸造工艺方面的巨大潜力，并最终为广泛的应用领域提供高性能产品。
{"title":"Nanotechnology-enhanced castability of wrought aluminum alloys 2024 and 6063","authors":"Guan-Cheng Chen , Xiaochun Li","doi":"10.1016/j.mfglet.2024.09.033","DOIUrl":"10.1016/j.mfglet.2024.09.033","url":null,"abstract":"<div><div>In the realm of high-performance applications, wrought aluminum alloys are esteemed for their high mechanical properties and excellent strength-to-weight ratio. However, their limited castability poses challenges in economically producing intricate structures through casting processes. To address this issue, a small proportion of TiC nanoparticles is introduced into the melts of AA 2024 and AA 6063 for nano-treating. This nano-treatment imparts several beneficial effects, including the delayed release of latent heat, inhibition of grain growth, and improvement of wettability. These effects enhance the fluidity of the melt, eliminate hot cracking, and elevate the surface quality of the castings. The outcomes underscore the promising potential of emerging nano-treatment technology in rendering traditionally non-castable wrought aluminum alloys suitable for cost-effective casting processes, ultimately delivering high-performance products for a wide range of applications.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 281-286"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.mfglet.2024.09.072
Austin Ngo , Noah Kohlhorst , Svitlana Fialkova , Bradley Jared , Tony Schmitz , Glenn Daehn , Jennifer L.W. Carter , Jian Cao , John J. Lewandowski
Additive Manufacturing (AM) processes have versatile capabilities but are susceptible to the formation of as-cast non-equilibrium microstructures, process-induced defects, and porosity, which have deleterious effects on the mechanical performance. As part of our NSF-ERC-HAMMER program, isothermal forging was investigated as a novel post-processing technique for refining microstructure, reducing process defect severity, and thereby improving mechanical properties. Specimens of Laser Powderbed Fusion (LPBF) AlSi10Mg were fabricated over a range of process parameters and tensile tested as a baseline. Initial work focused on duplicate AM material that was then hot forged with 20 % strain to investigate the effects of isothermal forging at one temperature and strain rate on the microstructure, tensile, and fatigue properties of the as-deposited materials. The microstructures, process-induced defect populations, and tensile/fatigue properties of both as-deposited and forged materials were quantified and analysed by OM, EBSD, XCT, and SEM by various NSF-ERC-HAMMER team members. Isothermal hot forging was found to induce recrystallisation and modify process-induced defect geometry along with increasing tensile ductility. The effects of AM deposition parameters and forge post-processing conditions on LPBF AlSi10Mg will be discussed in terms of microstructure, mechanical properties, and fractography.
增材制造（AM）工艺具有多功能性，但容易形成铸造时的非平衡微结构、工艺引起的缺陷和孔隙率，从而对机械性能产生有害影响。作为国家自然科学基金-环境科学研究中心-HAMMER 项目的一部分，等温锻造作为一种新型后处理技术进行了研究，以完善微观结构、减少工艺缺陷的严重程度，从而改善机械性能。在一定的工艺参数范围内制作了激光粉末熔床（LPBF）AlSi10Mg 试样，并作为基线进行了拉伸测试。最初的工作重点是复制 AM 材料，然后以 20% 的应变进行热锻，以研究在一个温度和应变率下进行等温锻造对沉积材料的微观结构、拉伸和疲劳性能的影响。国家自然科学基金委员会-能源研究中心-HAMMER 小组的多名成员通过 OM、EBSD、XCT 和 SEM 对沉积材料和锻造材料的微观结构、加工过程引起的缺陷群以及拉伸/疲劳性能进行了量化和分析。研究发现，等温热锻可诱导再结晶并改变工艺引起的缺陷几何形状，同时增加拉伸延展性。我们将从微观结构、机械性能和断口形貌方面讨论 AM 沉积参数和锻造后处理条件对 LPBF AlSi10Mg 的影响。
{"title":"Mechanical property improvements of LPBF-AlSi10Mg via forging to modify microstructure and defect characteristics","authors":"Austin Ngo , Noah Kohlhorst , Svitlana Fialkova , Bradley Jared , Tony Schmitz , Glenn Daehn , Jennifer L.W. Carter , Jian Cao , John J. Lewandowski","doi":"10.1016/j.mfglet.2024.09.072","DOIUrl":"10.1016/j.mfglet.2024.09.072","url":null,"abstract":"<div><div>Additive Manufacturing (AM) processes have versatile capabilities but are susceptible to the formation of as-cast non-equilibrium microstructures, process-induced defects, and porosity, which have deleterious effects on the mechanical performance. As part of our NSF-ERC-HAMMER program, isothermal forging was investigated as a novel post-processing technique for refining microstructure, reducing process defect severity, and thereby improving mechanical properties. Specimens of Laser Powderbed Fusion (LPBF) AlSi10Mg were fabricated over a range of process parameters and tensile tested as a baseline. Initial work focused on duplicate AM material that was then hot forged with 20 % strain to investigate the effects of isothermal forging at one temperature and strain rate on the microstructure, tensile, and fatigue properties of the as-deposited materials. The microstructures, process-induced defect populations, and tensile/fatigue properties of both as-deposited and forged materials were quantified and analysed by OM, EBSD, XCT, and SEM by various NSF-ERC-HAMMER team members. Isothermal hot forging was found to induce recrystallisation and modify process-induced defect geometry along with increasing tensile ductility. The effects of AM deposition parameters and forge post-processing conditions on LPBF AlSi10Mg will be discussed in terms of microstructure, mechanical properties, and fractography.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 568-574"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.mfglet.2024.09.090
Tony Schmitz , Elijah Charles , Brett Compton
This paper describes a physics-based, analytical model for additive friction stir deposition (AFSD) spindle speed selection to achieve a desired deposition temperature. In the model, power input to the feedstock, which enables plastic flow and deposition, is related to the material temperature rise and subsequent flow stress reduction using Fourier’s conduction rate equation. Power input is modeled as frictional heating at the deposit-surface interface and adiabatic heating due to plastic deformation. The flow stress is predicted using the strain, strain rate, and temperature-dependent Johnson-Cook constitutive model for the selected feedstock alloy. Model predictions are compared to AFSD numerical simulation results available in the literature and experiments for aluminum alloys.
{"title":"Analytical temperature model for spindle speed selection in additive friction stir deposition","authors":"Tony Schmitz , Elijah Charles , Brett Compton","doi":"10.1016/j.mfglet.2024.09.090","DOIUrl":"10.1016/j.mfglet.2024.09.090","url":null,"abstract":"<div><div>This paper describes a physics-based, analytical model for additive friction stir deposition (AFSD) spindle speed selection to achieve a desired deposition temperature. In the model, power input to the feedstock, which enables plastic flow and deposition, is related to the material temperature rise and subsequent flow stress reduction using Fourier’s conduction rate equation. Power input is modeled as frictional heating at the deposit-surface interface and adiabatic heating due to plastic deformation. The flow stress is predicted using the strain, strain rate, and temperature-dependent Johnson-Cook constitutive model for the selected feedstock alloy. Model predictions are compared to AFSD numerical simulation results available in the literature and experiments for aluminum alloys.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 720-729"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.mfglet.2024.09.056
Yan Chen, Yingge Zhou
Electrospinning is a versatile technique that is often used to fabricate ultra-fine fibers. With the help of a coaxial spinneret, microtubes can be fabricated as potential biomimetic capillary vessels. However, the sizes of electrospun microtubes in recent research were around 5 μm which is smaller to native capillary vessels (5–10 μm). The electrospun microtube diameter can be determined by various electrospinning parameters such as spinning materials, solvent, spinning distance, solution pump rate, applied voltage, etc. In this research, we explored the effects of spinning distance and core/sheath pump rate ratio on microtube diameter and wall thickness. Viscosity, wettability, and tensile tests were also conducted for microtube characterization. The results indicated that the microtube diameters range from 5 μm to 12 μm, which provides a promising direction for the fabrication of biomimetic capillary vessels.
{"title":"Clinical-relevant sized tubular capillary mimicries by sacrificial core-sheath electrospinning","authors":"Yan Chen, Yingge Zhou","doi":"10.1016/j.mfglet.2024.09.056","DOIUrl":"10.1016/j.mfglet.2024.09.056","url":null,"abstract":"<div><div>Electrospinning is a versatile technique that is often used to fabricate ultra-fine fibers. With the help of a coaxial spinneret, microtubes can be fabricated as potential biomimetic capillary vessels. However, the sizes of electrospun microtubes in recent research were around 5 μm which is smaller to native capillary vessels (5–10 μm). The electrospun microtube diameter can be determined by various electrospinning parameters such as spinning materials, solvent, spinning distance, solution pump rate, applied voltage, etc. In this research, we explored the effects of spinning distance and core/sheath pump rate ratio on microtube diameter and wall thickness. Viscosity, wettability, and tensile tests were also conducted for microtube characterization. The results indicated that the microtube diameters range from 5 μm to 12 μm, which provides a promising direction for the fabrication of biomimetic capillary vessels.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 462-468"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.mfglet.2024.09.036
Xiaowei Yu , Mengyuan Chen , Ming Wang , Jennifer Bracey , Bradley Frieberg , Roland Koestner , Wai Ping Gloria Tam , David Titmuss , Nicholas Ware
Li-ion battery manufacturing process parameters are critical to the electrode properties and the final cell electrochemical performance. During the electrode drying process, the drying temperature plays a critical role on the binder migration, which affects the interfacial adhesion between the electrode and the current collector. However, the influence of the temperature on the properties of the binder material and the binder/current collector interface is yet unknown. In this work, we studied the effect of drying temperature on the interfacial adhesion between the binder and the current collector by direct coating of polyvinylidene fluoride (PVDF) solution on Al foil and then drying at various temperatures. The interfacial adhesion strength between the PVDF and the Al foil was significantly increased, from 9.72 N/m (dried at room temperature) to > 665.80 N/m (dried at 200 ℃) with increased temperature. DSC and XRD analyses showed the changes in the crystalline forms of PVDF under different drying temperature. This work revealed that the drying temperature during electrode manufacturing should be considered from the aspects of both binder migration in mid-stage and PVDF crystalline properties in late-stage solvent drying.
{"title":"Effect of drying temperature on binder/current collector interfacial adhesion in electrode manufacturing of Li-ion batteries","authors":"Xiaowei Yu , Mengyuan Chen , Ming Wang , Jennifer Bracey , Bradley Frieberg , Roland Koestner , Wai Ping Gloria Tam , David Titmuss , Nicholas Ware","doi":"10.1016/j.mfglet.2024.09.036","DOIUrl":"10.1016/j.mfglet.2024.09.036","url":null,"abstract":"<div><div>Li-ion battery manufacturing process parameters are critical to the electrode properties and the final cell electrochemical performance. During the electrode drying process, the drying temperature plays a critical role on the binder migration, which affects the interfacial adhesion between the electrode and the current collector. However, the influence of the temperature on the properties of the binder material and the binder/current collector interface is yet unknown. In this work, we studied the effect of drying temperature on the interfacial adhesion between the binder and the current collector by direct coating of polyvinylidene fluoride (PVDF) solution on Al foil and then drying at various temperatures. The interfacial adhesion strength between the PVDF and the Al foil was significantly increased, from 9.72 N/m (dried at room temperature) to > 665.80 N/m (dried at 200 ℃) with increased temperature. DSC and XRD analyses showed the changes in the crystalline forms of PVDF under different drying temperature. This work revealed that the drying temperature during electrode manufacturing should be considered from the aspects of both binder migration in mid-stage and PVDF crystalline properties in late-stage solvent drying.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 304-309"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Additive Manufacturing (AM) is a novel manufacturing process that enables the physical realization of a given 3D model via layered deposition. Material extrusion (MEX) is one of the most widely used forms of the various AM techniques, in which the screw extrusion-based AM (SEAM) processing offers the most versatile characteristics, in terms of material handling and flow rate capacities. It involves continuous extrusion of the semi-solid material via an extruder screw. Ironing is a common practice in MEX techniques, to maintain z-height and improve the surface morphologies while deposition. Most commercially used nozzles for MEX are thin-walled, such that the ratio of the nozzle width to the diameter (w/d) is close to 1. In this research, investigations on the ironing effect during screw extrusion-based material deposition are explored using a set of wider nozzles (w/d as high as 40). Special emphasis is laid on the deposited surface finish, interlayer strength, and geometrical conformance of the extrusion. The nozzle diameter and the stand-off distance (SOD) are also independently varied. It is found that the best dimensional stability is achieved when the SOD is set between 75 % and 100 % of the nozzle diameter. Ironing improved the surface finish and the interlayer strength in all instances, with an average improvement of 50 % and 200 %, respectively.
{"title":"Investigations on ironing parameters in screw extrusion additive manufacturing (SEAM)","authors":"Yash Gopal Mittal , Gopal Gote , Yogesh Patil , Avinash Kumar Mehta , Pushkar Kamble , K.P. Karunakaran","doi":"10.1016/j.mfglet.2024.09.102","DOIUrl":"10.1016/j.mfglet.2024.09.102","url":null,"abstract":"<div><div><em>Additive Manufacturing</em> (AM) is a novel manufacturing process that enables the physical realization of a given 3D model via layered deposition. <em>Material extrusion</em> (MEX) is one of the most widely used forms of the various AM techniques, in which the <em>screw extrusion</em>-based AM (SEAM) processing offers the most versatile characteristics, in terms of material handling and flow rate capacities. It involves continuous extrusion of the semi-solid material via an extruder screw. Ironing is a common practice in MEX techniques, to maintain <em>z</em>-height and improve the surface morphologies while deposition. Most commercially used nozzles for MEX are thin-walled, such that the ratio of the nozzle width to the diameter (<em>w/d</em>) is close to 1. In this research, investigations on the ironing effect during screw extrusion-based material deposition are explored using a set of wider nozzles (<em>w/d</em> as high as 40). Special emphasis is laid on the deposited surface finish, interlayer strength, and geometrical conformance of the extrusion. The nozzle diameter and the <em>stand-off distance</em> (SOD) are also independently varied. It is found that the best dimensional stability is achieved when the SOD is set between 75 % and 100 % of the nozzle diameter. Ironing improved the surface finish and the interlayer strength in all instances, with an average improvement of 50 % and 200 %, respectively.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 822-831"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The state of the interface between the workpiece and the cutting tool affects the cutting temperature and pressure on the tool surface during the cutting process. In particular, while cutting difficult-to-cut materials such as Ni-based alloy 718, the workpiece exhibits a high affinity for cutting tool materials and could easily adhere to them. Adhesion can, at times, adversely affect productivity. The diffusion between the cutting tool and the workpiece is a factor considered to contribute to the adhesion phenomenon during cutting. Addressing this issue involves choosing tool materials and coated materials with high resistance to diffusion and optimizing cutting conditions, particularly the cutting speed, which significantly impacts cutting temperature. However, because cutting tool wear comprises various forms, clarifying the effect of diffusion on tool wear remains open. In this study, to reproduce the diffusion phenomenon between cutting tool and workpiece, two pairs of test specimens were prepared: (1) cemented carbide-AISI 1045 and (2) cemented carbide-Alloy718, which could be held at high temperature under vacuum conditions by a forging press. The degree of diffusion phenomena was evaluated at each tool-work material interface, and the quantification of diffusion amount was performed by diffused element in each work material. Additionally, the theoretical analysis of the diffusion phenomenon using the thermodynamic and phase diagram calculation software Thermo-Calc was also performed.
{"title":"Evaluation and quantification of diffusion wear between cutting chip and workpiece using forging press","authors":"Junichi Nakagawa , Yusuke Yoshimi , Katsumasa Chiba , Ryutaro Tanaka","doi":"10.1016/j.mfglet.2024.09.075","DOIUrl":"10.1016/j.mfglet.2024.09.075","url":null,"abstract":"<div><div>The state of the interface between the workpiece and the cutting tool affects the cutting temperature and pressure on the tool surface during the cutting process. In particular, while cutting difficult-to-cut materials such as Ni-based alloy 718, the workpiece exhibits a high affinity for cutting tool materials and could easily adhere to them. Adhesion can, at times, adversely affect productivity. The diffusion between the cutting tool and the workpiece is a factor considered to contribute to the adhesion phenomenon during cutting. Addressing this issue involves choosing tool materials and coated materials with high resistance to diffusion and optimizing cutting conditions, particularly the cutting speed, which significantly impacts cutting temperature. However, because cutting tool wear comprises various forms, clarifying the effect of diffusion on tool wear remains open. In this study, to reproduce the diffusion phenomenon between cutting tool and workpiece, two pairs of test specimens were prepared: (1) cemented carbide-AISI 1045 and (2) cemented carbide-Alloy718, which could be held at high temperature under vacuum conditions by a forging press. The degree of diffusion phenomena was evaluated at each tool-work material interface, and the quantification of diffusion amount was performed by diffused element in each work material. Additionally, the theoretical analysis of the diffusion phenomenon using the thermodynamic and phase diagram calculation software Thermo-Calc was also performed.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 588-594"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.mfglet.2024.09.057
Jigar Krushna Pathak, N. Ramesh Babu, D.S. Srinivasu
Laser beam welding (LBW) is widely used for welding Ti6Al4V alloys in aerospace applications. LBW has localized high-energy fluence with low-energy input compared to other fusion welding processes, resulting in narrower heat-affected zones. On the other hand, most metals are highly reflective when the laser beam impinges perpendicular to the surface, making the process inefficient. Hence, this work proposes to employ shallow angle incidence to reduce the reflectivity during the welding of Ti6Al4V material. To explore the potential of this idea, the current study focuses on studying the effect of laser incident angle (15°-90°), power (300 W-1500 W), and feed rate (10 mm/s-25 mm/s) on autogenous weld bead geometry. For this purpose, bead-on plate (BOP) LBW is conducted on mill-annealed Ti6Al4V material of dimensions 25 mm × 25 mm × 3 mm by employing a fiber laser source with a maximum power of 3 kW and a wavelength of 1080 nm. It is observed from the results that at a normal incident angle and low laser power (< 600 W), the penetration depth is too low to generate a weld bead. Analyzing the cross-section of the weld bead, obtained from SEM, perpendicular to the weld direction reveals that the increase in laser incident angle up to an optimal angle resulted in increased bead dimensions (width and height), and beyond that, the dimensions decreased. However, the optimal incident angle changed when the laser power was changed. The major finding of this study is that at 600 W and a normal incident angle, the laser could not penetrate and generate a weld bead due to low absorptivity, while at an incident angle of 300, 450, and 600, weld beads are generated because of increased absorptivity. Similarly, the increase in weld dimensions with the increase in laser power is observed. At higher laser power, underfill and oxide formation are observed. The feed rate is less predominant than the incident angle and the power.
激光束焊接（LBW）广泛应用于航空航天领域的 Ti6Al4V 合金焊接。与其他熔化焊接工艺相比，激光束焊接具有局部高能通量和低能量输入的特点，因此热影响区更窄。另一方面，当激光束垂直于金属表面时，大多数金属都具有很强的反射性，从而使焊接过程效率低下。因此，这项工作建议在焊接 Ti6Al4V 材料时采用浅角入射来降低反射率。为了探索这一想法的潜力，目前的研究侧重于研究激光入射角（15°-90°）、功率（300 W-1500 W）和进给速度（10 mm/s-25 mm/s）对自生焊珠几何形状的影响。为此，采用最大功率为 3 kW、波长为 1080 nm 的光纤激光源，在尺寸为 25 mm × 25 mm × 3 mm 的轧制退火 Ti6Al4V 材料上进行了焊珠在板上 (BOP) 低温焊接。从结果中可以看出，在正常入射角和低激光功率（< 600 W）条件下，穿透深度太低，无法产生焊珠。通过扫描电子显微镜（SEM）获得的垂直于焊接方向的焊缝横截面分析表明，激光入射角增加到最佳角度时，焊缝尺寸（宽度和高度）增加，超过最佳角度后，焊缝尺寸减小。然而，当激光功率改变时，最佳入射角也随之改变。这项研究的主要发现是，在 600 W 和正常入射角时，由于吸收率低，激光无法穿透并产生焊珠，而在 300、450 和 600 入射角时，由于吸收率增加，焊珠得以产生。同样，随着激光功率的增加，焊缝尺寸也会增加。在较高的激光功率下，会出现填充不足和氧化物形成。与入射角和功率相比，进给速度的影响较小。
{"title":"Effect of laser beam incident angle on welding of Ti6Al4V with fiber lasers","authors":"Jigar Krushna Pathak, N. Ramesh Babu, D.S. Srinivasu","doi":"10.1016/j.mfglet.2024.09.057","DOIUrl":"10.1016/j.mfglet.2024.09.057","url":null,"abstract":"<div><div>Laser beam welding (LBW) is widely used for welding Ti6Al4V alloys in aerospace applications. LBW has localized high-energy fluence with low-energy input compared to other fusion welding processes, resulting in narrower heat-affected zones. On the other hand, most metals are highly reflective when the laser beam impinges perpendicular to the surface, making the process inefficient. Hence, this work proposes to employ shallow angle incidence to reduce the reflectivity during the welding of Ti6Al4V material. To explore the potential of this idea, the current study focuses on studying the effect of laser incident angle (15°-90°), power (300 W-1500 W), and feed rate (10 mm/s-25 mm/s) on autogenous weld bead geometry. For this purpose, bead-on plate (BOP) LBW is conducted on mill-annealed Ti6Al4V material of dimensions 25 mm × 25 mm × 3 mm by employing a fiber laser source with a maximum power of 3 kW and a wavelength of 1080 nm. It is observed from the results that at a normal incident angle and low laser power (< 600 W), the penetration depth is too low to generate a weld bead. Analyzing the cross-section of the weld bead, obtained from SEM, perpendicular to the weld direction reveals that the increase in laser incident angle up to an optimal angle resulted in increased bead dimensions (width and height), and beyond that, the dimensions decreased. However, the optimal incident angle changed when the laser power was changed. The major finding of this study is that at 600 W and a normal incident angle, the laser could not penetrate and generate a weld bead due to low absorptivity, while at an incident angle of 30<sup>0</sup>, 45<sup>0</sup>, and 60<sup>0</sup>, weld beads are generated because of increased absorptivity. Similarly, the increase in weld dimensions with the increase in laser power is observed. At higher laser power, underfill and oxide formation are observed. The feed rate is less predominant than the incident angle and the power.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 469-474"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.mfglet.2024.09.059
Fahim Shariar , Umut Karagüzel , Yiğit Karpat
Since various material properties of carbon fiber-reinforced polymer (CFRP) are temperature dependent, dry drilling of CFRP is a delicate process. Thermal damage can be caused by a rise in temperature during drilling due to a large portion of heat being transferred into the material. Heat partition is used to quantify this, which represents the percentage of total heat being dissipated into the constituent objects during a machining operation. Drill margin and contact conditions at the tool-workpiece interface significantly affect the drilling of CFRP material. Drilling experiments were performed to measure thrust force, torque, and temperatures for five different sets of feed rates and rotational speeds. This study proposes a method for calculating heat partition values during CFRP drilling by developing a finite element-based thermal model. The FE model employs a Gaussian distributed ring-type heat flux that is a function of the equivalent contact length at the interface between the drill and the material surface and the geometry of the workpiece which operates as a moving heat source, emulating the progress of the drill through the CFRP laminate. The tool implements heat fluxes that use characteristic time-point-based step functions to represent the temperature on the drill as it advances through the workpiece during machining. The temperature profiles obtained from the FE analysis and the experiments for the workpiece and tool were subsequently matched iteratively to determine the corresponding heat partition value.
由于碳纤维增强聚合物（CFRP）的各种材料特性与温度有关，因此碳纤维增强聚合物的干式钻孔是一个微妙的过程。在钻孔过程中，由于大量热量传入材料，温度升高会造成热损伤。热分区用于量化这种情况，它表示在加工操作过程中散失到组成物体中的热量占总热量的百分比。钻孔余量和刀具-工件界面的接触条件对 CFRP 材料的钻孔有很大影响。钻孔实验测量了五组不同进给率和转速下的推力、扭矩和温度。本研究通过开发基于有限元的热模型，提出了一种计算 CFRP 钻孔过程中热分区值的方法。该有限元模型采用高斯分布环型热通量，它是钻头与材料表面界面等效接触长度和工件几何形状的函数，可作为移动热源，模拟钻头穿过 CFRP 层压板的过程。该工具使用基于时间点的特征阶跃函数实现热通量，以表示钻头在加工过程中穿过工件时的温度。从 FE 分析和实验中获得的工件和刀具的温度曲线随后进行迭代匹配，以确定相应的热分区值。
{"title":"Heat partition evaluation during dry drilling of thick CFRP laminates with polycrystalline diamond drills","authors":"Fahim Shariar , Umut Karagüzel , Yiğit Karpat","doi":"10.1016/j.mfglet.2024.09.059","DOIUrl":"10.1016/j.mfglet.2024.09.059","url":null,"abstract":"<div><div>Since various material properties of carbon fiber-reinforced polymer (CFRP) are temperature dependent, dry drilling of CFRP is a delicate process. Thermal damage can be caused by a rise in temperature during drilling due to a large portion of heat being transferred into the material. Heat partition is used to quantify this, which represents the percentage of total heat being dissipated into the constituent objects during a machining operation. Drill margin and contact conditions at the tool-workpiece interface significantly affect the drilling of CFRP material. Drilling experiments were performed to measure thrust force, torque, and temperatures for five different sets of feed rates and rotational speeds. This study proposes a method for calculating heat partition values during CFRP drilling by developing a finite element-based thermal model. The FE model employs a Gaussian distributed ring-type heat flux that is a function of the equivalent contact length at the interface between the drill and the material surface and the geometry of the workpiece which operates as a moving heat source, emulating the progress of the drill through the CFRP laminate. The tool implements heat fluxes that use characteristic time-point-based step functions to represent the temperature on the drill as it advances through the workpiece during machining. The temperature profiles obtained from the FE analysis and the experiments for the workpiece and tool were subsequently matched iteratively to determine the corresponding heat partition value.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 483-493"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.mfglet.2024.09.043
Advay Pawar , Bruce Anderson , Behnam Pourdeyhimi , Amy L. McNulty , Matthew Fisher , Rohan Shirwaiker
Scaffolds, in addition to being biocompatible, should possess structural and mechanical properties similar to the natural tissues they intend to replace. Many tissue engineering applications require porous 3D scaffolds characterized by unique microfibrous organization and mechanical anisotropy. Manufacturing process principles and process parameter-biomaterial interactions ultimately govern the properties that can be achieved in the scaffold. In this study, we investigate a recently developed nonwoven scaffold fabrication process, 3D melt blowing (3DMB), for processing Elastollan®, a thermoplastic polyurethane with basic mechanical properties suitable for musculoskeletal tissue engineering. The range of feasible processing parameters was screened and the effects of two sets of critical process parameters (fiber deposition offset and surface velocity of the collector) that produced contrasting scaffold morphologies were assessed. Results showed that scaffolds of Group B that were fabricated at the higher fiber deposition offset (90 %) and higher surface velocity of the collector (6 × 105 mm/min) possessed significantly smaller fiber diameter and higher porosity and degree of fiber alignment along the principal direction of collector rotation during 3DMB (all p < 0.05) compared to Group A scaffolds (fabricated at 50 % offset and 1 × 105 mm/min surface velocity). Although both groups possessed similar tensile stiffness, the elongation at failure was significantly different (p < 0.0001). The higher elongation at failure of Group B correlated with the higher degree of fiber alignment in these scaffolds. In contrast, the more isotropic fibrous organization of Group A contributed to their higher compressive stiffness (p = 0.004). The introduction of NaOH treatment to improve hydrophilicity of the scaffolds resulted in a significant reduction of tensile stiffness of Group A (p < 0.05) but not Group B. This treatment did not significantly affect the elongation at failure or compressive stiffness of both groups. With NaOH-treatment, both groups demonstrated good biocompatibility when seeded with fibroblast cells over 14 days. This study confirms the ability to fabricate via 3DMB, biocompatible, micro-fibrous, Elastollan scaffolds relevant for musculoskeletal tissue engineering.
支架除了具有生物相容性外，还应该具有与要替代的天然组织相似的结构和机械特性。许多组织工程应用要求多孔三维支架具有独特的微纤维组织和机械各向异性。制造工艺原理以及工艺参数与生物材料之间的相互作用最终决定了支架所能达到的性能。在本研究中，我们研究了最近开发的一种无纺布支架制造工艺--三维熔体吹塑（3DMB），用于加工 Elastollan®，这是一种热塑性聚氨酯，具有适合肌肉骨骼组织工程的基本机械性能。对可行的加工参数范围进行了筛选，并评估了两组关键加工参数（纤维沉积偏移量和收集器表面速度）对产生截然不同的支架形态的影响。结果显示，与 A 组支架（以 50% 的偏移量和 1 × 105 mm/min 的表面速度制造）相比，以较高的纤维沉积偏移量（90%）和较高的收集器表面速度（6 × 105 mm/min）制造的 B 组支架具有明显较小的纤维直径、较高的孔隙率以及在 3DMB 期间沿收集器主要旋转方向的纤维排列程度（所有 p < 0.05）。虽然两组具有相似的拉伸刚度，但破坏时的伸长率却有显著差异（p < 0.0001）。B 组较高的破坏伸长率与这些支架中较高的纤维排列程度有关。相比之下，A 组的纤维组织各向同性更强，因此抗压刚度更高（p = 0.004）。为提高支架的亲水性而引入 NaOH 处理会显著降低 A 组的拉伸刚度（p < 0.05），但不会降低 B 组的拉伸刚度。经 NaOH 处理后，两组在 14 天内播种成纤维细胞时均表现出良好的生物相容性。这项研究证实了通过 3DMB 制造生物相容性微纤维 Elastollan 支架的能力，这种支架适用于肌肉骨骼组织工程。
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