Guangjing Huang, Dongdong Gu, Hong Liu, Kaijie Lin, Rui Wang, He Sun
Graded multi-material parts achieve a compositionally graded transition between two different materials, mitigating undesirable consequences such as cracking and delamination due to property mismatch and significantly improving the comprehensive performance of parts. In this study, the Ti6Al4V/AlMgScZr-graded multi-material parts were fabricated using laser powder bed fusion technology, introducing a composition-graded layer with 25 wt.% Ti6Al4V and 75 wt.% AlMgScZr at the interface to reduce the mismatch between the two materials. The effect of the graded layer’s laser scanning speed on the densification behavior, microstructure evolution, and mechanical properties of the Ti6Al4V/AlMgScZr-graded multi-material parts was investigated. It was revealed that the crack area at the interface reduced from 0.325 to 0.067 mm2 as the scanning speed increased from 2400 to 2800 mm/s and then increased to 0.161 mm2 at 3000 mm/s. A smooth, continuous-graded layer with good metallurgical bonding was fabricated at 2800 mm/s. The TiAl3 intermetallic compound was formed at the interface and underwent a transition from rod-like to coarse dendritic and finally to finer dendritic structure along the building direction. The Ti6Al4V/AlMgScZr-graded multi-material parts exhibited a graded decrease in microhardness from 374 HV0.2 on the Ti6Al4V side to 122 HV0.2 on the AlMgScZr side, and an excellent compressive strength of 1531 MPa was obtained at the optimal parameter of 2800 mm/s.
{"title":"The role of graded layers in interfacial characteristics and mechanical properties of Ti6Al4V/AlMgScZr-graded multi-material parts fabricated using laser powder bed fusion","authors":"Guangjing Huang, Dongdong Gu, Hong Liu, Kaijie Lin, Rui Wang, He Sun","doi":"10.36922/msam.3088","DOIUrl":"https://doi.org/10.36922/msam.3088","url":null,"abstract":"Graded multi-material parts achieve a compositionally graded transition between two different materials, mitigating undesirable consequences such as cracking and delamination due to property mismatch and significantly improving the comprehensive performance of parts. In this study, the Ti6Al4V/AlMgScZr-graded multi-material parts were fabricated using laser powder bed fusion technology, introducing a composition-graded layer with 25 wt.% Ti6Al4V and 75 wt.% AlMgScZr at the interface to reduce the mismatch between the two materials. The effect of the graded layer’s laser scanning speed on the densification behavior, microstructure evolution, and mechanical properties of the Ti6Al4V/AlMgScZr-graded multi-material parts was investigated. It was revealed that the crack area at the interface reduced from 0.325 to 0.067 mm2 as the scanning speed increased from 2400 to 2800 mm/s and then increased to 0.161 mm2 at 3000 mm/s. A smooth, continuous-graded layer with good metallurgical bonding was fabricated at 2800 mm/s. The TiAl3 intermetallic compound was formed at the interface and underwent a transition from rod-like to coarse dendritic and finally to finer dendritic structure along the building direction. The Ti6Al4V/AlMgScZr-graded multi-material parts exhibited a graded decrease in microhardness from 374 HV0.2 on the Ti6Al4V side to 122 HV0.2 on the AlMgScZr side, and an excellent compressive strength of 1531 MPa was obtained at the optimal parameter of 2800 mm/s.","PeriodicalId":503695,"journal":{"name":"Materials Science in Additive Manufacturing","volume":" 55","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140990890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Excellent mechanical properties and biocompatibility are the most sought-after attributes in biomedical materials for the regeneration of damaged tissues. However, conventional dense titanium alloys possess a modulus significantly higher than that of human tissues, leading to potential stress-shielding effects. Medical porous titanium alloys can reduce the elastic modulus of the material, promote tissue fixation and vascular regeneration, and improve the suitability for human tissue properties. With the continuous development of technology, the preparation process of porous titanium alloys has undergone a series of multifaceted transformations and improvements in the aspects of powder sintering, fiber preparation, and additive manufacturing processes, and its structural characteristics and mechanical properties are constantly evolving in a controllable direction. Alongside the enhancement of the material’s mechanical properties through porous design, optimization of the properties at the implant-tissue interface also leads to improved antimicrobial and osteogenic properties of porous titanium. Due to the complex internal structure of porous titanium alloys, surface modification is mainly carried out in fluid media, which is realized by morphological modification and the introduction of functional substances. Over time, the surface modification of porous titanium alloys for medical applications has progressed from morphological modification and introduction of chemical composition to the loading of bioactive substances. This evolution aims to enhance safety and efficiency in the use of these materials. This paper reviews the preparation and surface modification processes of porous titanium alloys for medical use and summarizes the advantages, disadvantages, and influencing factors among different processes, with a view to providing new ideas for the development of porous implants for medical use.
{"title":"Porous titanium alloys for medical application: Progress in preparation process and surface modification research","authors":"Binghao Wang, Miao Luo, Zheng Shi, Yuwei Cui, Yuting Lv, Chengliang Yang, Liqiang Wang","doi":"10.36922/msam.2753","DOIUrl":"https://doi.org/10.36922/msam.2753","url":null,"abstract":"Excellent mechanical properties and biocompatibility are the most sought-after attributes in biomedical materials for the regeneration of damaged tissues. However, conventional dense titanium alloys possess a modulus significantly higher than that of human tissues, leading to potential stress-shielding effects. Medical porous titanium alloys can reduce the elastic modulus of the material, promote tissue fixation and vascular regeneration, and improve the suitability for human tissue properties. With the continuous development of technology, the preparation process of porous titanium alloys has undergone a series of multifaceted transformations and improvements in the aspects of powder sintering, fiber preparation, and additive manufacturing processes, and its structural characteristics and mechanical properties are constantly evolving in a controllable direction. Alongside the enhancement of the material’s mechanical properties through porous design, optimization of the properties at the implant-tissue interface also leads to improved antimicrobial and osteogenic properties of porous titanium. Due to the complex internal structure of porous titanium alloys, surface modification is mainly carried out in fluid media, which is realized by morphological modification and the introduction of functional substances. Over time, the surface modification of porous titanium alloys for medical applications has progressed from morphological modification and introduction of chemical composition to the loading of bioactive substances. This evolution aims to enhance safety and efficiency in the use of these materials. This paper reviews the preparation and surface modification processes of porous titanium alloys for medical use and summarizes the advantages, disadvantages, and influencing factors among different processes, with a view to providing new ideas for the development of porous implants for medical use.","PeriodicalId":503695,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"113 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140370771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Direct energy deposition (DED)-based additive manufacturing facilitates fabrication of medium-to-large functional parts. This study assesses the role of varying scan strategies and dwell time between each layer to control the cooling rate of 316L stainless steel produced by the laser-engineered net shaping-DED method. Customized print patterns were designed, keeping other optimized print parameters constant to obtain printed parts with better dimensional tolerance. The parts, which were >99% dense, were fabricated in a controlled argon environment. A heterogeneous microstructure consisting of a cellular columnar and equiaxed substructure was obtained. Two-dimensional X-ray diffraction revealed the presence of a single-phase γ-austenitic FCC phase. A refined microstructure with less elemental segregation was noticed with an increase in dwell time between the print layers. Internal defect analysis using X-ray micro-computed tomography revealed low lack-of-fusion voids along the build direction without any micro-cracks, which is attributed to higher cooling rates between subsequent print layers. As demonstrated in a mechanical performance evaluation of tensile and micro-hardness properties, better performance can be achieved by controlling the cooling rate and customizing deposition patterns.
基于直接能量沉积（DED）的增材制造技术有助于制造中大型功能部件。本研究评估了不同的扫描策略和每层之间的停留时间对控制激光工程净成形-DED 方法生产的 316L 不锈钢冷却速率的作用。在保持其他优化打印参数不变的情况下，设计了定制打印模式，以获得尺寸公差更好的打印部件。这些部件的密度大于 99%，是在受控的氩气环境中制造的。获得了由蜂窝状柱状和等轴状亚结构组成的异质微观结构。二维 X 射线衍射显示存在单相的 γ-austenitic FCC 相。随着打印层之间停留时间的增加，微观结构更加细化，元素偏析减少。利用 X 射线显微计算机断层扫描技术进行的内部缺陷分析表明，沿构建方向的熔合空隙较小，没有出现任何微裂缝，这归因于后续打印层之间的冷却速率较高。拉伸和微硬度机械性能评估表明，通过控制冷却速率和定制沉积模式可以获得更好的性能。
{"title":"Role of customized scan strategies and dwell time on microstructure and properties of additively manufactured 316L stainless steel","authors":"Puskar Pathak, G. Majkic, V. Selvamanickam","doi":"10.36922/msam.2676","DOIUrl":"https://doi.org/10.36922/msam.2676","url":null,"abstract":"Direct energy deposition (DED)-based additive manufacturing facilitates fabrication of medium-to-large functional parts. This study assesses the role of varying scan strategies and dwell time between each layer to control the cooling rate of 316L stainless steel produced by the laser-engineered net shaping-DED method. Customized print patterns were designed, keeping other optimized print parameters constant to obtain printed parts with better dimensional tolerance. The parts, which were >99% dense, were fabricated in a controlled argon environment. A heterogeneous microstructure consisting of a cellular columnar and equiaxed substructure was obtained. Two-dimensional X-ray diffraction revealed the presence of a single-phase γ-austenitic FCC phase. A refined microstructure with less elemental segregation was noticed with an increase in dwell time between the print layers. Internal defect analysis using X-ray micro-computed tomography revealed low lack-of-fusion voids along the build direction without any micro-cracks, which is attributed to higher cooling rates between subsequent print layers. As demonstrated in a mechanical performance evaluation of tensile and micro-hardness properties, better performance can be achieved by controlling the cooling rate and customizing deposition patterns.","PeriodicalId":503695,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140257269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. L. Goh, Samuel Lee, Shi Hui Cheng, Daniel Jee Seng Goh, Pothunuri Laya, Van Pho Nguyen, Boon Siew Han, Wai Yee Yeong
In the rapidly expanding field of additive manufacturing, multi-material fused filament fabrication represents a frontier with vast potential for creating composite structures that blend the benefits of different material properties. Interlaminar adhesion between dissimilar materials remains a challenge for the realization of multifunctional structure for practical use. This study investigates the interlaminar adhesion between conductive polylactic acid and thermoplastic polyurethane, materials representative of rigid and flexible characteristics, respectively. We present a comparative analysis of two adhesion enhancement approaches: the incorporation of mechanical interlocking features and the modification of surface roughness at the interface. Through tensile testing, we evaluate the effectiveness of these methods against a benchmark coupon with unmodified interface. Micro-computed tomography analysis, surface morphology analysis, and mechanical performance assessments elucidate the failure modes and provide insights into the interfacial behavior of these interface designs. We found that the interface design with top infill modification showed the highest interlaminar adhesion strength, with an improvement of at least 25% compared to the benchmark coupon. Our findings aim to inform the design and manufacturing practices in multi-material 3D printing and to open new avenues for the development of multifunctional, composite 3D-printed systems.
{"title":"Enhancing interlaminar adhesion in multi-material 3D printing: A study of conductive PLA and TPU interfaces through fused filament fabrication","authors":"G. L. Goh, Samuel Lee, Shi Hui Cheng, Daniel Jee Seng Goh, Pothunuri Laya, Van Pho Nguyen, Boon Siew Han, Wai Yee Yeong","doi":"10.36922/msam.2672","DOIUrl":"https://doi.org/10.36922/msam.2672","url":null,"abstract":"In the rapidly expanding field of additive manufacturing, multi-material fused filament fabrication represents a frontier with vast potential for creating composite structures that blend the benefits of different material properties. Interlaminar adhesion between dissimilar materials remains a challenge for the realization of multifunctional structure for practical use. This study investigates the interlaminar adhesion between conductive polylactic acid and thermoplastic polyurethane, materials representative of rigid and flexible characteristics, respectively. We present a comparative analysis of two adhesion enhancement approaches: the incorporation of mechanical interlocking features and the modification of surface roughness at the interface. Through tensile testing, we evaluate the effectiveness of these methods against a benchmark coupon with unmodified interface. Micro-computed tomography analysis, surface morphology analysis, and mechanical performance assessments elucidate the failure modes and provide insights into the interfacial behavior of these interface designs. We found that the interface design with top infill modification showed the highest interlaminar adhesion strength, with an improvement of at least 25% compared to the benchmark coupon. Our findings aim to inform the design and manufacturing practices in multi-material 3D printing and to open new avenues for the development of multifunctional, composite 3D-printed systems.","PeriodicalId":503695,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"11 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140425283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhongji Sun, Verner Soh, Coryl Jing Jun Lee, Delvin Wuu, Desmond Lau, Siyuan Wei, Chee Koon Ng, S. Sing, Dennis Tan, Pei Wang
Hot cracking is a major bottleneck preventing the additive manufacturing community from adopting precipitation-strengthened nickel-base superalloys, such as the IN738LC. Prior literature demonstrates the beneficial outcome of increasing the carbon content within IN738LC to alleviate its hot cracking problem. However, the effect of carbon content on the gamma prime precipitation and grain recrystallization was not fully addressed. Here, we fabricated five sample sets of IN738LC with different carbon contents and subjected these samples to two separate heat treatment processes. The precipitate and grain evolution were monitored under the backscattered electron imaging and electron backscattered diffraction studies. While the carbon addition could assist in addressing the hot cracking problem, horizontal delamination cracks were detected during the fabrication of large samples when the overall carbon content was above 0.4 wt.%, highlighting the need for care when introducing carbon for the purpose of resolving hot cracking.
{"title":"Effects of carbon content on precipitate evolution and crack susceptibility in additively manufactured IN738LC","authors":"Zhongji Sun, Verner Soh, Coryl Jing Jun Lee, Delvin Wuu, Desmond Lau, Siyuan Wei, Chee Koon Ng, S. Sing, Dennis Tan, Pei Wang","doi":"10.36922/msam.2264","DOIUrl":"https://doi.org/10.36922/msam.2264","url":null,"abstract":"Hot cracking is a major bottleneck preventing the additive manufacturing community from adopting precipitation-strengthened nickel-base superalloys, such as the IN738LC. Prior literature demonstrates the beneficial outcome of increasing the carbon content within IN738LC to alleviate its hot cracking problem. However, the effect of carbon content on the gamma prime precipitation and grain recrystallization was not fully addressed. Here, we fabricated five sample sets of IN738LC with different carbon contents and subjected these samples to two separate heat treatment processes. The precipitate and grain evolution were monitored under the backscattered electron imaging and electron backscattered diffraction studies. While the carbon addition could assist in addressing the hot cracking problem, horizontal delamination cracks were detected during the fabrication of large samples when the overall carbon content was above 0.4 wt.%, highlighting the need for care when introducing carbon for the purpose of resolving hot cracking.","PeriodicalId":503695,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"53 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140449843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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