In order to prevent the deformation of the part, enhance heat conduction, and establish a stable foundation, additional support structures are typically incorporated beneath the parts during the selective laser melting (SLM) process. These structures are subsequently eliminated once the SLM process is completed, thereby facilitating the attainment of near-net forming. Therefore, their SLM processing parameters should be different from those of the solid parts to obtain the desirable functions and removability. However, there is so far very little research focusing on the optimization of the SLM processing parameters of the support structures compared with the solid objects. In this work, the widely used block support was illustrated as an instance, and an optimization strategy of its SLM processing parameters was provided. The effects of laser power, scanning speed, and layer thickness on the morphology and qualities of single track, support sample, and support tensile sample were systematically investigated. The results showed that the SLM processing parameters have a significant impact on the properties of the block support by regulating the qualities of the single tracks. At last, a group of optimal SLM processing parameters (80 W of laser power, 400 mm/s of scanning speed, 60 μm of layer thickness) was determined for the Ti-6Al-4V titanium alloy, and the corresponding ultimate tensile strength of the support structure reached 416 MPa.
{"title":"Study on the effects of the processing parameters on the single tracks and the block support structures fabricated by selective laser melting","authors":"Tao Zhang, Kaifei Zhang, Qi Chen, Yuanzhen Pang","doi":"10.2351/7.0001222","DOIUrl":"https://doi.org/10.2351/7.0001222","url":null,"abstract":"In order to prevent the deformation of the part, enhance heat conduction, and establish a stable foundation, additional support structures are typically incorporated beneath the parts during the selective laser melting (SLM) process. These structures are subsequently eliminated once the SLM process is completed, thereby facilitating the attainment of near-net forming. Therefore, their SLM processing parameters should be different from those of the solid parts to obtain the desirable functions and removability. However, there is so far very little research focusing on the optimization of the SLM processing parameters of the support structures compared with the solid objects. In this work, the widely used block support was illustrated as an instance, and an optimization strategy of its SLM processing parameters was provided. The effects of laser power, scanning speed, and layer thickness on the morphology and qualities of single track, support sample, and support tensile sample were systematically investigated. The results showed that the SLM processing parameters have a significant impact on the properties of the block support by regulating the qualities of the single tracks. At last, a group of optimal SLM processing parameters (80 W of laser power, 400 mm/s of scanning speed, 60 μm of layer thickness) was determined for the Ti-6Al-4V titanium alloy, and the corresponding ultimate tensile strength of the support structure reached 416 MPa.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139606346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hui Jiao, Qingyuan Liu, Guanghui Zhang, Ze Lin, Jia Zhou, Yuxing Huang, Yuhong Long
To investigate the interaction mechanism between a laser, water jet, and substrate, a model is developed to simulate the temperature field evolution and removal process during water jet-guided laser (WJGL) cutting of silicon. The model accounted for the temperature-dependent properties of the silicon absorption coefficient, as well as the physical processes of solid-liquid-gas phase change. A three-dimensional finite volume model of WJGL cutting of silicon is created, incorporating laser energy input, water jet impact-cooling, and silicon phase transition and removal. The volume of fluid (VOF) method is employed to trace the interphase interface and obtain the groove shape. The validity of the model is verified by comparing simulation results with experimental data. The simulation results show that the groove cross section is characterized by a “V” shape. The groove depth nonlinearly increases from 52 to 385 μm with an increasing number of cuts. Additionally, the residual temperature of the silicon substrate rises from 837 to 1345 K as the number of scans increases from 1 to 10. The findings offer valuable insights into WJGL cutting research, specifically shedding light on the intricate details of the laser-water jet-substrate interaction mechanism.
{"title":"Numerical investigations of water jet-guided laser cutting of silicon","authors":"Hui Jiao, Qingyuan Liu, Guanghui Zhang, Ze Lin, Jia Zhou, Yuxing Huang, Yuhong Long","doi":"10.2351/7.0001268","DOIUrl":"https://doi.org/10.2351/7.0001268","url":null,"abstract":"To investigate the interaction mechanism between a laser, water jet, and substrate, a model is developed to simulate the temperature field evolution and removal process during water jet-guided laser (WJGL) cutting of silicon. The model accounted for the temperature-dependent properties of the silicon absorption coefficient, as well as the physical processes of solid-liquid-gas phase change. A three-dimensional finite volume model of WJGL cutting of silicon is created, incorporating laser energy input, water jet impact-cooling, and silicon phase transition and removal. The volume of fluid (VOF) method is employed to trace the interphase interface and obtain the groove shape. The validity of the model is verified by comparing simulation results with experimental data. The simulation results show that the groove cross section is characterized by a “V” shape. The groove depth nonlinearly increases from 52 to 385 μm with an increasing number of cuts. Additionally, the residual temperature of the silicon substrate rises from 837 to 1345 K as the number of scans increases from 1 to 10. The findings offer valuable insights into WJGL cutting research, specifically shedding light on the intricate details of the laser-water jet-substrate interaction mechanism.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139607950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Gutjahr, Milton Pereira, Jurandir Marcos Sá de Sousa, H. S. Ferreira, Anselmo Thiesen Júnior
The feedstock capture efficiency on powder laser directed energy deposition (L-DED) is becoming a big challenge in the industrial use of the L-DED process for the manufacturing of large-scale AM parts. The powder capture efficiency is dependent on process optimization and the toolpath. The current literature presents a vast range of usual powder efficiency, between 3% and 32% and in some specific cases exceeding 90%. In L-DED, the powder-gas jet stream interacts with the laser beam adding material locally onto the substrate. Part of this material is captured by the melt pool. The not captured material that is affected by the laser beam suffers degradation. In the literature, there is a lack of studies related to powder reuse in the L-DED process. This paper presents a comprehensive study on the consequence of laser interaction with SS 316L metal powder particles during the L-DED process using a range of different powder characterization techniques to assess the powder morphology, size distribution, chemical composition, followability, and density. The study was conducted within eight powder reuse cycles, without adding virgin material to the powder batch. Reduction of particle size distribution range, increase in circularity, and improvement in the powder flowability were identified as consequences of powder reuse. The result of laser interaction with particles was further explored by scanning electron microscopy, presenting the continuous modification of the particles across the eight reuse cycles. The oxygen content on the particles was also measured to access the O2 pick-up as a consequence of particle heating.
粉末激光定向能沉积（L-DED）的原料捕获效率正成为工业化使用 L-DED 工艺制造大规模 AM 零件的一大挑战。粉末捕获效率取决于工艺优化和工具路径。目前的文献显示，通常的粉末效率范围很大，介于 3% 和 32% 之间，在某些特定情况下超过 90%。在 L-DED 中，粉末气流与激光束相互作用，在基底上局部添加材料。部分材料被熔池捕获。未被激光束捕获的材料则会发生降解。文献中缺乏与 L-DED 工艺中粉末再利用相关的研究。本文采用一系列不同的粉末表征技术，对 L-DED 工艺中激光与 SS 316L 金属粉末颗粒相互作用的后果进行了全面研究，以评估粉末形态、尺寸分布、化学成分、可随性和密度。这项研究是在八个粉末重复使用周期内进行的，没有在粉末批次中添加原始材料。研究发现，粉末重复使用会导致粒度分布范围缩小、圆度增加和粉末流动性改善。扫描电子显微镜进一步探究了激光与颗粒相互作用的结果，显示了颗粒在八个重复使用周期中的持续变化。此外，还测量了颗粒上的氧含量，以了解颗粒加热后的氧气吸收情况。
{"title":"Powder degradation as a consequence of laser interaction: A study of SS 316L powder reuse on the laser directed energy deposition process","authors":"J. Gutjahr, Milton Pereira, Jurandir Marcos Sá de Sousa, H. S. Ferreira, Anselmo Thiesen Júnior","doi":"10.2351/7.0001093","DOIUrl":"https://doi.org/10.2351/7.0001093","url":null,"abstract":"The feedstock capture efficiency on powder laser directed energy deposition (L-DED) is becoming a big challenge in the industrial use of the L-DED process for the manufacturing of large-scale AM parts. The powder capture efficiency is dependent on process optimization and the toolpath. The current literature presents a vast range of usual powder efficiency, between 3% and 32% and in some specific cases exceeding 90%. In L-DED, the powder-gas jet stream interacts with the laser beam adding material locally onto the substrate. Part of this material is captured by the melt pool. The not captured material that is affected by the laser beam suffers degradation. In the literature, there is a lack of studies related to powder reuse in the L-DED process. This paper presents a comprehensive study on the consequence of laser interaction with SS 316L metal powder particles during the L-DED process using a range of different powder characterization techniques to assess the powder morphology, size distribution, chemical composition, followability, and density. The study was conducted within eight powder reuse cycles, without adding virgin material to the powder batch. Reduction of particle size distribution range, increase in circularity, and improvement in the powder flowability were identified as consequences of powder reuse. The result of laser interaction with particles was further explored by scanning electron microscopy, presenting the continuous modification of the particles across the eight reuse cycles. The oxygen content on the particles was also measured to access the O2 pick-up as a consequence of particle heating.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139612975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lifang Mei, Yang Liu, Dongbing Yan, Jun Yang, Yu Liang, Shanming Luo
The study employed laser scanning welding technology for butt welding experiments on red copper, investigating the behavior of metal vapor plumes, plasma, and metal spatter during the welding process, as well as the quality and electrical conductivity of the resulting joints by varying the polarity and strength of the applied magnetic field. The results showed that the polarity of the magnetic field had a minor effect on welding performance, with the main influencing factor being the strength of the magnetic field. As the magnetic field strength increased, the formation volume and ejection intensity of metal vapor plumes and plasma exhibited an initial decrease followed by an increase, similarly affecting the weld seam morphology, mechanical properties, and electrical conductivity. At 120 mT magnetic strength, metal vapor and plasma formation are minimized, and metal spattering is eliminated, thereby enhancing welding stability; the weld seam was uniformly formed with no significant defects; the cross-sectional weld was even without obvious undulations; on one side of the weld zone, columnar crystals were extremely fine, and the center of the weld consisted of numerous equiaxed crystals with a few columnar crystals perpendicular to the horizontal direction, while the equiaxed crystals on the other side of the weld zone were denser; the sample joints achieved peak hardness and tensile strength at 70.9 HV and 202 MPa, showing increases of 17.2% and 14.8%, respectively, over nonmagnetic conditions; the weldment’s conductivity peaked at 79.58 mS/m, 36.5% higher than without a magnetic field, reaching 97.9% of the parent material’s.
{"title":"Experimental study on magnetic field-assisted laser scanning welding of T2 copper","authors":"Lifang Mei, Yang Liu, Dongbing Yan, Jun Yang, Yu Liang, Shanming Luo","doi":"10.2351/7.0001245","DOIUrl":"https://doi.org/10.2351/7.0001245","url":null,"abstract":"The study employed laser scanning welding technology for butt welding experiments on red copper, investigating the behavior of metal vapor plumes, plasma, and metal spatter during the welding process, as well as the quality and electrical conductivity of the resulting joints by varying the polarity and strength of the applied magnetic field. The results showed that the polarity of the magnetic field had a minor effect on welding performance, with the main influencing factor being the strength of the magnetic field. As the magnetic field strength increased, the formation volume and ejection intensity of metal vapor plumes and plasma exhibited an initial decrease followed by an increase, similarly affecting the weld seam morphology, mechanical properties, and electrical conductivity. At 120 mT magnetic strength, metal vapor and plasma formation are minimized, and metal spattering is eliminated, thereby enhancing welding stability; the weld seam was uniformly formed with no significant defects; the cross-sectional weld was even without obvious undulations; on one side of the weld zone, columnar crystals were extremely fine, and the center of the weld consisted of numerous equiaxed crystals with a few columnar crystals perpendicular to the horizontal direction, while the equiaxed crystals on the other side of the weld zone were denser; the sample joints achieved peak hardness and tensile strength at 70.9 HV and 202 MPa, showing increases of 17.2% and 14.8%, respectively, over nonmagnetic conditions; the weldment’s conductivity peaked at 79.58 mS/m, 36.5% higher than without a magnetic field, reaching 97.9% of the parent material’s.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139624869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kosei Yamamoto, Ryuhei Matsuda, K. Takenaka, Yuji Sato, Y. Yamashita, Ayahito Saikai, Taisei Yachi, M. Kusaba, Masahiro Tsukamoto
A tungsten carbide–cobalt (WC–Co) composite layer was formed on a stainless-steel type 304 (SS304) substrate using multibeam laser metal deposition (LMD) with blue diode lasers. This paper aims to provide WC–Co layer formation with low porosity and high layer formation efficiency by using the multibeam LMD process. The effects of process parameters such as laser output power and powder feed rate are tied together to explain the geometry of the melt layer as well as the fraction of the laser energy used for melting a material. The experimental results show that the porosity rate and layer formation efficiency were recorded at 0.3% and 0.0042 mm3/J, respectively, at the laser output power of 180 W and a powder feed rate of 75 mg/s. It was revealed that layer formation efficiency was dependent on the laser output power.
{"title":"Experimental evaluation of a WC–Co alloy layer formation process by multibeam-type laser metal deposition with blue diode lasers","authors":"Kosei Yamamoto, Ryuhei Matsuda, K. Takenaka, Yuji Sato, Y. Yamashita, Ayahito Saikai, Taisei Yachi, M. Kusaba, Masahiro Tsukamoto","doi":"10.2351/7.0001125","DOIUrl":"https://doi.org/10.2351/7.0001125","url":null,"abstract":"A tungsten carbide–cobalt (WC–Co) composite layer was formed on a stainless-steel type 304 (SS304) substrate using multibeam laser metal deposition (LMD) with blue diode lasers. This paper aims to provide WC–Co layer formation with low porosity and high layer formation efficiency by using the multibeam LMD process. The effects of process parameters such as laser output power and powder feed rate are tied together to explain the geometry of the melt layer as well as the fraction of the laser energy used for melting a material. The experimental results show that the porosity rate and layer formation efficiency were recorded at 0.3% and 0.0042 mm3/J, respectively, at the laser output power of 180 W and a powder feed rate of 75 mg/s. It was revealed that layer formation efficiency was dependent on the laser output power.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138950508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Skin-pass rolls are used for setting the final sheet thickness and surface texture. For sheet metal that is produced for forming, textured skin-pass rolls featuring a high-low structure are used in order to improve the formability and paint adhesion of the sheet. In this paper, new textures for skin-pass rolls generated by high-speed laser melt injection (HSLMI) are presented and characterized. Furthermore, it is studied how the texture of the roll is transferred to steel and aluminum sheets. With HSLMI, metal matrix composite (MMC) layers featuring spherical fused tungsten carbide (SFTC) particles with a high hardness could be produced on skin-pass rolls. For generating an increased high-low structure, laser ablation and electrolytic etching were carried out after HSLMI and grinding of the rolls. An analysis of the topography showed that different protruding heights between SFTC particles and matrix can be set. The textures generated by laser ablation showed a topography featuring two homogeneous height levels, whereas a texture with spherically shaped particles could be generated by electrolytic etching. Furthermore, it was found that all textures were transferred from the roll to both steel and aluminum sheets. The transfer of the textures mainly depended on the protruding height of the SFTC particles and the SFTC particle content of the roll.
{"title":"Texturing skin-pass rolls by high-speed laser melt injection, laser ablation, and electrolytic etching","authors":"P. Warneke, A. Bohlen, T. Seefeld","doi":"10.2351/7.0001149","DOIUrl":"https://doi.org/10.2351/7.0001149","url":null,"abstract":"Skin-pass rolls are used for setting the final sheet thickness and surface texture. For sheet metal that is produced for forming, textured skin-pass rolls featuring a high-low structure are used in order to improve the formability and paint adhesion of the sheet. In this paper, new textures for skin-pass rolls generated by high-speed laser melt injection (HSLMI) are presented and characterized. Furthermore, it is studied how the texture of the roll is transferred to steel and aluminum sheets. With HSLMI, metal matrix composite (MMC) layers featuring spherical fused tungsten carbide (SFTC) particles with a high hardness could be produced on skin-pass rolls. For generating an increased high-low structure, laser ablation and electrolytic etching were carried out after HSLMI and grinding of the rolls. An analysis of the topography showed that different protruding heights between SFTC particles and matrix can be set. The textures generated by laser ablation showed a topography featuring two homogeneous height levels, whereas a texture with spherically shaped particles could be generated by electrolytic etching. Furthermore, it was found that all textures were transferred from the roll to both steel and aluminum sheets. The transfer of the textures mainly depended on the protruding height of the SFTC particles and the SFTC particle content of the roll.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138952039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Panda, Seshadev Sahoo, Cheruvu Siva Kumar, Ashish Kumar Nath
The utilization of the laser powder bed fusion (L-PBF) method in additive manufacturing experiments has revealed the intriguing potential to induce morphological evolutions within the solidification microstructure by manipulating the thermal conditions. Transitions of this nature can have a substantial impact on the ultimate texture and material properties of the product. This study utilizes numerical investigations to examine the microstructure evolution of the AlSi10Mg alloy, which is fabricated using the L-PBF process, under different thermal conditions. In order to investigate the changes in the microstructure, we employ a parameter phase-field (PF) model. This model effectively replicates the natural development of nuclei from inoculant particles and accurately simulates the transitions in the morphology. The PF model’s validity is determined through the numerical investigation of morphological transitions during directional solidification of the AlSi10Mg alloy. The model’s predictions are then compared to the analytical Hunt model. The formation of a columnar microstructure with a significantly reduced secondary dendrite arm spacing is observed when the ratio of the temperature gradient (G) to the solidification rate (R) is increased.
{"title":"Investigating the influence of thermal behavior on microstructure during solidification in laser powder bed fusion of AlSi10Mg alloys: A phase-field analysis","authors":"B. Panda, Seshadev Sahoo, Cheruvu Siva Kumar, Ashish Kumar Nath","doi":"10.2351/7.0001243","DOIUrl":"https://doi.org/10.2351/7.0001243","url":null,"abstract":"The utilization of the laser powder bed fusion (L-PBF) method in additive manufacturing experiments has revealed the intriguing potential to induce morphological evolutions within the solidification microstructure by manipulating the thermal conditions. Transitions of this nature can have a substantial impact on the ultimate texture and material properties of the product. This study utilizes numerical investigations to examine the microstructure evolution of the AlSi10Mg alloy, which is fabricated using the L-PBF process, under different thermal conditions. In order to investigate the changes in the microstructure, we employ a parameter phase-field (PF) model. This model effectively replicates the natural development of nuclei from inoculant particles and accurately simulates the transitions in the morphology. The PF model’s validity is determined through the numerical investigation of morphological transitions during directional solidification of the AlSi10Mg alloy. The model’s predictions are then compared to the analytical Hunt model. The formation of a columnar microstructure with a significantly reduced secondary dendrite arm spacing is observed when the ratio of the temperature gradient (G) to the solidification rate (R) is increased.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138996053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aqeel Mohd, Gautam J. P., Anusha E., Shariff S. M.
In the present study, a high beam quality fiber-coupled diode laser was effectively utilized to weld 10-mm thick Inconel 617 superalloy in single pass. Influence of critical parameters of focusing distance and welding speed on weld characteristics was systematically investigated and optimized. At optimum process conditions with the power density of ≈106 W/cm2, crack-free full-penetration weld with minimal distortion, porosity, and no underfill/undercut/root-hump defects were obtained with 97%–99% joint efficiency. The weld joint quality produced was on par with multipass employing conventional lasers and advanced laser-hybrid welding techniques and sufficient enough to apply in various applications of thermal power plants, ship building, and heavy industries.
{"title":"High-power fiber-coupled diode laser welding of 10-mm thick Inconel 617 superalloy","authors":"Aqeel Mohd, Gautam J. P., Anusha E., Shariff S. M.","doi":"10.2351/7.0001209","DOIUrl":"https://doi.org/10.2351/7.0001209","url":null,"abstract":"In the present study, a high beam quality fiber-coupled diode laser was effectively utilized to weld 10-mm thick Inconel 617 superalloy in single pass. Influence of critical parameters of focusing distance and welding speed on weld characteristics was systematically investigated and optimized. At optimum process conditions with the power density of ≈106 W/cm2, crack-free full-penetration weld with minimal distortion, porosity, and no underfill/undercut/root-hump defects were obtained with 97%–99% joint efficiency. The weld joint quality produced was on par with multipass employing conventional lasers and advanced laser-hybrid welding techniques and sufficient enough to apply in various applications of thermal power plants, ship building, and heavy industries.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138998068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Additive manufacturing of copper using laser powder bed fusion enables the production of highly complex components with excellent heat and electrical conductivity. However, the processing of copper by means of near-infrared laser radiation, which is commonly used, is challenging due to its high reflectivity. Nevertheless, it has been demonstrated that high densities and electrical conductivities can be achieved using high-power laser systems. In order to process pure copper with reliable quality with different machines, it is essential to understand the conditions at which a continuous weld track is formed. For this purpose, weld tracks with varying laser power and scan speeds were welded on a copper substrate plate with an applied powder layer. The preheating temperature of the substrate plate and the beam size were varied to test different process conditions. The melt pool depths and widths were measured, and a relationship was elaborated. Based on these results, cube samples with discrete weld tracks on top were manufactured. The melt pool depth was measured and compared with the predicted melt pool depth to investigate the transferability of the elaborated relationship from the substrate to process conditions. It was found that with rising preheating temperature and for larger beam diameters at the same peak intensity, the weld width and weld depths increase. Furthermore, continuous weld tracks formed reliably in the keyhole welding regime. A good agreement between the weld depth of weld tracks on the substrate and the elaborated relationship was revealed. However, the weld tracks were shallower than predicted.
{"title":"Influence of temperature and beam size on weld track shape in laser powder bed fusion of pure copper using near-infrared laser system","authors":"Alexander Bauch, Dirk Herzog","doi":"10.2351/7.0001118","DOIUrl":"https://doi.org/10.2351/7.0001118","url":null,"abstract":"Additive manufacturing of copper using laser powder bed fusion enables the production of highly complex components with excellent heat and electrical conductivity. However, the processing of copper by means of near-infrared laser radiation, which is commonly used, is challenging due to its high reflectivity. Nevertheless, it has been demonstrated that high densities and electrical conductivities can be achieved using high-power laser systems. In order to process pure copper with reliable quality with different machines, it is essential to understand the conditions at which a continuous weld track is formed. For this purpose, weld tracks with varying laser power and scan speeds were welded on a copper substrate plate with an applied powder layer. The preheating temperature of the substrate plate and the beam size were varied to test different process conditions. The melt pool depths and widths were measured, and a relationship was elaborated. Based on these results, cube samples with discrete weld tracks on top were manufactured. The melt pool depth was measured and compared with the predicted melt pool depth to investigate the transferability of the elaborated relationship from the substrate to process conditions. It was found that with rising preheating temperature and for larger beam diameters at the same peak intensity, the weld width and weld depths increase. Furthermore, continuous weld tracks formed reliably in the keyhole welding regime. A good agreement between the weld depth of weld tracks on the substrate and the elaborated relationship was revealed. However, the weld tracks were shallower than predicted.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138971167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yang Zou, Shaoqi Shi, Zefeng Yang, Teng Xu, Yongqi Liang, Qiang Yu, Yuchuan Cheng, Gaojie Xu, Zhixiang Li, Fei Long
Laser cladding (LC) process parameters have a substantial influence on coating morphology and mechanical characteristics; it is necessary to optimize key parameters for laser processing. In this study, Stellite12 cobalt-based alloy powder with excellent corrosion and wear resistance was selected as the cladding material. The multi-objective optimization model of the LC process was established by response surface methodology, laser power, scanning speed, and powder feeding rate as input factors, and the target response variables involve dilution, aspect ratio, and microhardness of the single-track cladding. Combined with variance analysis (ANOVA), the multi-objective optimization of laser power, scanning speed, and powder feeding rate was conducted. A single-track cladding layer with a dilution of 18.29%, an aspect ratio of 3.88, and a microhardness of 634.67 HV0.2 was obtained using the optimized process parameters. Errors between the predicted and actual values of single-track cladding dilution, aspect ratio, and microhardness were less than 8%, which verified the accuracy of the established model.
{"title":"Multi-objective optimization of key process parameters in laser cladding Stellite12 cobalt-based alloy powder","authors":"Yang Zou, Shaoqi Shi, Zefeng Yang, Teng Xu, Yongqi Liang, Qiang Yu, Yuchuan Cheng, Gaojie Xu, Zhixiang Li, Fei Long","doi":"10.2351/7.0001163","DOIUrl":"https://doi.org/10.2351/7.0001163","url":null,"abstract":"Laser cladding (LC) process parameters have a substantial influence on coating morphology and mechanical characteristics; it is necessary to optimize key parameters for laser processing. In this study, Stellite12 cobalt-based alloy powder with excellent corrosion and wear resistance was selected as the cladding material. The multi-objective optimization model of the LC process was established by response surface methodology, laser power, scanning speed, and powder feeding rate as input factors, and the target response variables involve dilution, aspect ratio, and microhardness of the single-track cladding. Combined with variance analysis (ANOVA), the multi-objective optimization of laser power, scanning speed, and powder feeding rate was conducted. A single-track cladding layer with a dilution of 18.29%, an aspect ratio of 3.88, and a microhardness of 634.67 HV0.2 was obtained using the optimized process parameters. Errors between the predicted and actual values of single-track cladding dilution, aspect ratio, and microhardness were less than 8%, which verified the accuracy of the established model.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139004791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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