Anisotropy in the impact toughness of selective laser melted Ti–6Al–4V alloy

Wu, Ming-Wei; Lai, Pang-Hsin; Chen, Jhewn‐Kuang

doi:10.1016/j.msea.2015.10.045

Cited by 103 publications

(39 citation statements)

References 20 publications

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“…• Titanium alloys: Titanium alloy, specifically Ti-6Al-4V [72,[137][138][139][140][141][142][143], is the most investigated material for SLM process. Manufacturing titanium alloys via conventional methods is relatively difficult, since Ti is highly reactive and sensitive to chemical impurities, such as O, N and H. With this regard, SLM is superior to conventional manufacturing methods since the inert gas in the SLM chamber can provide a protective atmosphere.…”

Section: Materials Manufactured With Slmmentioning

confidence: 99%

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Deng

2018

Linköping Studies in Science and Technology. Licentiate Thesis

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Linköping 2018Cover image: A fracture surface of EBM IN718 after tensile test at room temperature.During the course of research underlying this thesis, Dunyong Deng was enrolled in Agora Materiae, a multidiciplinary doctoral program at Linköping University, Sweden. Printed by LiU-Tryck 2018 © Dunyong Deng AbstractAdditive manufacturing (AM), also known as 3D printing, has gained significant interest in aerospace, energy, automotive and medical industries due to its capabilities of manufacturing components that are either prohibitively costly or impossible to manufacture by conventional processes. Among the various additive manufacturing processes for metallic components, electron beam melting (EBM) and selective laser melting (SLM) are two of the most widely used powder bed based processes, and have shown great potential for manufacturing high-end critical components, such as turbine blades and customized medical implants. The futures of the EBM and SLM are doubtlessly promising, but to fully realize their potentials there are still many challenges to overcome.Inconel 718 (IN718) is a nickel-base superalloy and has impressive combination of good mechanical properties and low cost. Though IN718 is being mostly used as a turbine disk material now, the initial introduction of IN718 was to overcome the poor weldability of superalloys in 1960s, since sluggish precipitation of strengthening phases γ ′ /γ ′′ enables good resistance to strain-age cracking during welding or post weld heat treatment. Given the similarity between AM and welding processes, IN718 has been widely applied to the metallic AM field to facilitate the understandings of process-microstructure-property relationships.The work presented in this licentiate thesis aims to better understand microstructures and mechanical properties EBM and SLM IN718, which have not been systematically investigated. Microstructures of EBM and SLM IN718 have been characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and correlated with the process conditions. Monotonic mechanical properties (e.g., Vickers microhardness and tensile properties) have also been measured and rationalized with regards to the microstructure evolutions before and after heat treatments.For EBM IN718, the results show the microstructure is not homogeneous but dependant on the location in the components, and the anisotropic mechanical properties are probably attributed to alignment of porosities rather than texture.iii Post heat treatment can slightly increase the mechanical strength compared to the as-manufactured condition but does not alter the anisotropy. SLM IN718 shows significantly different microstructure and mechanical properties to EBM IN718. The as-manufactured SLM IN718 has very fine dendritic microstructure and Laves phases in the interdendrites, and is "work-hardened" by the residual strains and dislocations present in the material. Mechanical properties are different between horizontally and vertically built samples, and heat treatment can m...

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Section: Materials Manufactured With Slmmentioning

confidence: 99%

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Deng

2018

Linköping Studies in Science and Technology. Licentiate Thesis

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“…Согласно результатам испытаний на растяже-ние можно сделать вывод, что в большинстве слу-чаев вертикальные образцы имеют прочностные свойства ниже, чем горизонтальные, что под-тверждается исследованиями в работах [2,15,17,[23][24]. Значения относительного удлинения об-разцов демонстрируют обратную зависимость: ве-личина δ больше у вертикальных образцов.…”

Section: результаты исследований и их обсуждениеunclassified

“…В изделиях, полученных по технологии селек-тивного лазерного плавления, помимо специфич-ной структуры могут присутствовать дефекты -главным образом это микротрещины и поры [2,[13][14][15][16][17][18]. Последние разделяют на два основных вида.…”

Section: Introductionunclassified

“…Поры, образующиеся из-за недостаточного про-плавления порошкового слоя. В результате в мес-тах, где частицы расплавились не полностью либо не произошло «слияния» расплавленных частиц порошка с ранее обработанным слоем, образуются плоские поры, расположенные перпендикулярно направлению выращивания [2,[15][16][17].…”

Section: Introductionunclassified

“…Поры второго типа оказывают значительно большее влияние на механические свойства мате-риала вследствие их большего размера, а также пло-ской формы [13][14][15][16][17][18]. Для уменьшения пористости в конечных изделиях ответственного назначения применяется горячее изостатическое прессование, во многих случаях позволяющее существенно по-высить качество изделий после СЛП [19].…”

Section: Introductionunclassified

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Anisotropy of Mechanical Properties of Products Manufactured Using Selective Laser Melting of Powdered Materials

Popovich¹,

Sufiiarov²,

Борисов³

et al. 2016

Izv. VUZ. Poroshk. Met.

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Рассмотрены причины возникновения анизотропии свойств в изделиях, изготавливаемых по технологии селективного лазерного плавления металлических порошковых материалов. Представлены результаты оценки механических свойств образцов из сплавов основе титана Ti-6Al-4V, ВТ6 и жаропрочного никелевого сплава Inconel 718 в различных направ-лениях. Исследована микроструктура компактных образцов, полученных селективным лазерным плавлением. Приведе-на зависимость их механических свойств от ориентации заготовок относительно рабочей платформы установки. Анализ микрошлифов из сплава Ti-6Al-4V показал, что у образца прямоугольной формы направление зеренной структуры со-ответствует направлению выращивания, тогда как при изготовлении тонких элементов сетчатой конструкции за счет их меньшего сечения протекают иные тепловые процессы, что сказывается на условиях кристаллизации и формирующейся микроструктуре: в зависимости от угла наклона элемента сетчатой конструкции изменяются направление и форма зерен. Anisotropy of mechanical properties of products manufactured using selective laser melting of powdered materialsThe paper examines factors leading to anisotropy of properties in products manufactured using lasercusing, a technology consisting in selective laser melting of metal powdered materials. The results obtained when evaluating mechanical properties of specimens made of titanium alloys Ti-6Al-4V, VT6 and heat-resistant nickel alloy Inconel 718 in different directions are presented. The study covers the microstructure of compact specimens obtained using selective laser melting, and describes dependence of their mechanical properties on workpiece orientation with relation to the unit working platform. The study of Ti-6Al-4V microsections showed that the direction of the rectangular specimen grain structure matched the growth direction, whereas thin elements with a lattice structure were made with other thermal processes due to their smaller cross section. This affected crystallization conditions and microstructure being formed: grain directions and shapes changed depending on the lattice structure element inclination.Keywords: additive manufacturing, selective laser melting, powder metallurgy, titanium alloys, nickel alloys, layer-by-layer manufacturing, anisotropy, mechanical properties. ВведениеТехнология селективного лазерного плавления (СЛП) уже сейчас активно применяется для из-готовления металлических изделий, что связано с возможностью производства заготовок, макси-мально близких по своей конфигурации к конеч-ному изделию, напрямую из компьютерной мо-дели, без использования оснастки. Это позволяет экономить материалы и затраты на последующую обработку, а также обеспечивает свободу выбо-ра формы изделий, которая может существенно повысить эксплуатационные характеристики де-талей [1]. Последнее особенно актуально в таких областях, как авиация и медицина. В авиации, где титановые и никелевые сплавы получили широ-кое распространение, предъявляются особенные требования к массе изделий. Применение адди-тивных технологий позволя...

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Impact Toughness of As‐Built and Heat‐Treated Near‐β Ti–5Al–5Mo–5V–3Cr–1Zr Alloys Fabricated by Selective Laser Melting and Electron Beam Melting

et al. 2021

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Herein, the effects of heat treatment on the microstructure evolution and impact toughness of selective laser‐melted (SLM) and electron beam‐melted (EBM) near‐β Ti–5Al–5Mo–5V–3Cr–1Zr (Ti55531) alloy specimens are systematically investigated. As fabricated SLM and EBM Ti55531 alloys contain metastable β and α + β microstructure, respectively. The metastable β microstructure of SLM‐fabricated Ti55531 is transformed to bilamellar, lamellar, and bimodal structure after supertransus triplex heat treatment, hot isostatic pressing and α/β solution and aging treatments, respectively. In the EBM‐fabricated Ti55531 specimens, the defects are effectively eliminated after hot isostatic pressing. The correlation between microstructure and impact toughness of as‐built and heat‐treated specimens are elucidated. Both SLM and EBM specimens with lamellar microstructure show a high impact toughness due to the deflecting effect on crack propagation of α lamella. In addition, hot isostatic pressing further enhance the impact toughness of EBM‐fabricated Ti55531 via eliminating the defects formed during the fabrication process. This work demonstrates that heat treatment is a potential way to tailor the microstructure and enhanced the impact toughness of additive manufactured near‐β Ti alloys.

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Anisotropy in the impact toughness of selective laser melted Ti–6Al–4V alloy

Cited by 103 publications

References 20 publications

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Anisotropy of Mechanical Properties of Products Manufactured Using Selective Laser Melting of Powdered Materials

Impact Toughness of As‐Built and Heat‐Treated Near‐β Ti–5Al–5Mo–5V–3Cr–1Zr Alloys Fabricated by Selective Laser Melting and Electron Beam Melting

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