Article
Engineering, Manufacturing
Yanjun Liu, Longbin Xu, Chunlei Qiu
Summary: Optimized laser powder bed fusion (L-PBF) process can produce metastable titanium alloy with high yield strength and good elongation, and the microstructure features certain amounts of α laths, ω precipitates, and Mo atomic clusters.
ADDITIVE MANUFACTURING
(2022)
Article
Nanoscience & Nanotechnology
Yanfang Wang, Xin Lin, Nan Kang, Zihong Wang, Qingzheng Wang, Yuxi Liu, Weidong Huang
Summary: In this study, Zr-modified 2024Al alloy deposits were prepared using L-PBF technology, with the addition of 1.3wt% Zr, which reduced the solidification cracking susceptibility and improved the grain structure of the alloy. After T6 heat treatment, the yield strength and ultimate tensile strength of the alloy were further increased, reaching comparable or even higher levels than conventional wrought alloys.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Engineering, Manufacturing
Simon Bergmueller, Josef Scheiber, Lukas Kaserer, Gerhard Leichtfried
Summary: This study demonstrates the effectiveness of dual laser (DL) powder bed fusion (PBF) combined with in situ heat treatment (HT) in promoting the formation of equiaxed grains in high-carbon high-speed steel. The overlapping of melting and heating laser beams significantly affects the solidification microstructure, resulting in a fine-grained equiaxed microstructure with exceptional mechanical properties. The study also shows that DL-PBF can reduce the temperature required for in situ HT.
ADDITIVE MANUFACTURING
(2023)
Article
Materials Science, Multidisciplinary
Yuchao Lei, Kenta Aoyagi, Akihiko Chiba
Summary: Site-specific control of solidification grain structure is achieved in manufacturing non-weldable superalloy Alloy713ELC using powder bed fusion additive manufacturing with an electron beam. The study establishes an analytical transient model to simulate the heat transfer during the process and validates it with numerical models. The mechanisms of columnar grain refinement and columnar-to-equiaxed transition (CET) are rationalized and related to the variations of solidification direction and convection within mushy zone. Based on the understanding of the grain structure evolution mechanisms, a method to manipulate CET or achieve an interlocked zigzag grain structure is proposed.
Article
Materials Science, Multidisciplinary
Xing Zhu, Zhiguang Zhu, Tingting Liu, Wenhe Liao, Yulei Du, Huiliang Wei
Summary: In this study, highly dense and crack-free AA2024 samples were successfully additively manufactured by inoculation treatment of Zr-based metallic glass powders. The grain refinement in the LPBF-fabricated AA2024 alloy was achieved by the formation of Al3Zr particles, acting as heterogeneous nucleation sites. The complete routes for columnar-equiaxed transition were revealed by tailoring the concentration of nucleation particles and solidification conditions, leading to the formation of bimodal grain size distribution consisting of ultrafine grains and coarser grains.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Manufacturing
Cameron Barr, Aaron Pateras, Andrey Molotnikov, David Clarke, Milan Brandt
Summary: This study investigates the potential of manufacturing NAB components through laser powder bed fusion. The results show that as-built NAB has high strength but brittle performance, while heat-treated NAB exhibits similar properties to the wrought equivalent. As-built C95800, on the other hand, shows differences in elongation, strength, and corrosion behavior compared to NAB, but its heat-treated form is similar to cast NAB.
ADDITIVE MANUFACTURING
(2022)
Article
Materials Science, Multidisciplinary
S. Sanchez, G. Gaspard, C. J. Hyde, I. A. Ashcroft, G. A. Ravi, A. T. Clare
Summary: The performance of components manufactured by laser powder bed fusion (LPBF) is limited by microstructural defects and macroscale anomalies, resulting in lower mechanical properties compared to wrought counterparts. Research on creep behavior of LPBF alloy 718 showed that different scanning strategies and build orientations, along with heat treatment, significantly impacted creep life. LPBF has the potential to surpass wrought material properties, with build strategies proposed for high temperature creep applications.
MATERIALS & DESIGN
(2021)
Article
Engineering, Manufacturing
Holden Hyer, Abhishek Mehta, Kevin Graydon, Nemanja Kljestan, Marko Knezevic, David Weiss, Brandon McWilliams, Kyu Cho, Yongho Sohn
Summary: By utilizing CALPHAD calculation and Scheil solidification method, the potential of applying Al-8wt%Ce-10wt%Mg alloy in LPBF was evaluated. Through a comprehensive parametric study and microstructural characterization, a suitable range of laser power and scan speed for achieving >99% volumetric density was identified. However, decreasing the scan speed resulted in a decrease in Mg concentration and Vickers hardness.
ADDITIVE MANUFACTURING
(2022)
Article
Chemistry, Physical
Marvin Schuster, Anthony De Luca, Remo Widmer, Xavier Maeder, Christian Leinenbach
Summary: Additive manufacturing provides an opportunity to produce complex geometries with improved properties using novel alloys. This study investigates the precipitation formation and optimal process parameters of zirconium-modified 2618 alloy in laser powder bed fusion. The addition of zirconium results in crack-free, high-density material with a trimodal grain size distribution. The findings contribute to a better understanding of precipitate formation in Zr-modified 2xxx alloys and pave the way for the commercialization of further 2xxx alloys tailored to additive manufacturing.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Hao Zhang, Hang Su, Yaqing Hou, Xuandong Wang, Yazhou He, Fafa Li
Summary: Compositionally graded samples from pure Fe to Fe-27 %Cr were fabricated using laser powder bed fusion and in-situ alloying. The transformation from fine equiaxed grains to coarse columnar grains occurred with increasing Cr content, specifically between Fe-9Cr and Fe-12Cr compositions. The Fe-9Cr sample consisted of fine randomly oriented equiaxed grains, while the Fe-12Cr sample exhibited elongated columnar grains with a strong specialIntscript fiber texture. The microhardness of Fe-9Cr (190 HV0.5) was 22.6% higher compared to Fe-12Cr (155 HV0.5), due to the strengthening effect of the equiaxed structure.
Article
Nanoscience & Nanotechnology
Jack Peterson, Shota Kariya, Ammarueda Issariyapat, Junko Umeda, Katsuyoshi Kondoh
Summary: Understanding the oriented-to-misoriented transition (OMT) and its origins is crucial for additive manufacturing design processes. A technique for quickly mapping the OMT using X-ray diffraction was developed, with electron backscattered diffraction verification. The mapping revealed two independent transitions based on scan speed and volumetric energy densities (VED). In-situ single track scans showed that the scan speed-based OMT is caused by a decrease in penetration depth and larger equiaxed grain zones during weld pool solidification.
SCRIPTA MATERIALIA
(2023)
Article
Engineering, Manufacturing
Sagar Patel, Haoxiu Chen, Mihaela Vlasea, Yu Zou
Summary: The laser powder bed fusion of aluminium alloys is challenging due to their high reflectivity and thermal conductivity. This paper proposes a process parameter optimization method using processing diagrams, temperature prediction models, X-ray computed tomography, and metallography. By selecting suitable beam diameter and laser power settings, near fully dense parts can be achieved. The use of a dimensionless keyhole number and melt pool aspect ratio is also applied to describe different melting modes.
ADDITIVE MANUFACTURING
(2022)
Article
Engineering, Manufacturing
Mohammad Hossein Mosallanejad, Behzad Niroumand, Cristian Ghibaudo, Sara Biamino, Alessandro Salmi, Paolo Fino, Abdollah Saboori
Summary: Alloy design using Additive Manufacturing (AM) methods is an interesting research area. This paper addresses the challenges of strong texture, columnar grains, and chemical inhomogeneity in Ti6Al4V-7Cu alloy produced via Electron Beam Powder Bed Fusion (EB-PBF) method. The results show a relatively homogenous Cu distribution in the product and the conversion of beta columnar grains into equiaxed grains.
ADDITIVE MANUFACTURING
(2022)
Article
Nanoscience & Nanotechnology
Xu Yang, Yilong Wang, Wenqi Zhang, Yang Qi, Baopeng Zhang, Hu Zhang, Haihong Zhu
Summary: This study investigates the densification, microstructure, mechanical properties, strengthening mechanisms, and coarsening resistance of an LPBF-fabricated insitu precipitation-hardening Cu-1.8Cr-1.0Nb-2.0Fe copper alloy. The results show that optimal process parameters enable the fabrication of nearly full specimens with a relative density of 99.98%. The in-situ precipitation of an Nb(FeCr) core-shell nanostructure during the LPBF process induces a strong precipitation effect, resulting in an exceptional ultimate tensile strength of 444 MPa. Aging treatment further enhances the tensile strength through the formation of a reinforced phase and maintains the coarsening resistance of the Nb(FeCr) core-shell nanostructure. Precipitation strengthening is the dominant mechanism for both as-built and direct aging specimens.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Engineering, Manufacturing
Chi Zhang, Ye Zhou, Kai Wei, Qidong Yang, Junhan Zhou, Hao Zhou, Xiaoyu Zhang, Xujing Yang
Summary: The Invar 36 alloy was additively manufactured using laser powder bed fusion (PBF-LB), and comprehensive observations and experiments were conducted to study its microstructure, defects, metallography, high cycle fatigue behavior, and fractography. Insufficient laser energy density results in non-overlapping melting traces and the formation of numerous defects, leading to an inferior high cycle fatigue life. On the contrary, an adequate laser energy density significantly increases the overlap between adjacent melting traces, promoting the formation of favorable microstructures and low porosity. As a result, the Invar 36 alloy exhibits superior high cycle fatigue life, primarily attributed to small crack propagation, long crack propagation, and final fracture stages.
VIRTUAL AND PHYSICAL PROTOTYPING
(2023)
Article
Materials Science, Multidisciplinary
X. T. Wang, M. Liu, G. Y. Zhou, H. Jiang, X. Li, M. Luo, Y. H. Liu, Z. H. Zhang, G. H. Cao
Article
Engineering, Mechanical
M. Luo, M. Liu, X. T. Wang, M. C. Li, X. Li, Z. M. Ren, G. H. Cao, Z. H. Zhang
ENGINEERING FAILURE ANALYSIS
(2019)
Article
Nanoscience & Nanotechnology
Xintian Wang, Xingyu Pan, Pengyue Sun, Chunlei Qiu
Summary: By adding TiAl powder particles into CoCrFeMnNi HEA and processing with selective laser melting, the developed microstructure led to enhancements in 0.2% yield strength, ultimate tensile strength, and strain hardening rates. The presence of microstructural features such as L1(2) domains, intragranular precipitates, and grain boundary precipitates played a key role in improving the mechanical properties of the samples.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Xintian Wang, Chunlei Qiu
Summary: A selectively laser melted and hot isostatically pressed high entropy alloy was aged at different temperatures to study its microstructural evolution. The formation of nano-sized ordered structures and precipitates was observed at lower temperatures, while higher temperatures led to increased particle fractions and sizes with the disappearance of ordered structures. Samples with ordered structures and fine precipitates exhibited higher yield strength, ultimate tensile strength, and ductility compared to those without ordered structures and with larger precipitates.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Manufacturing
Xintian Wang, Fujin Qu, Chunlei Qiu
Summary: Selective laser melting of Ti-48Al-2Cr-2Nb often results in severe cracking, but the cracking mechanism is not well understood. Both bulk samples and samples with only several layers were prepared and examined. It was found that a freshly built layer consisted mainly of the alpha(2) phase, and gamma formed from alpha(2) during subsequent thermal cycling, with its volume fraction increasing continuously. The gamma phase had a higher density of geometrically necessary dislocations (GND) than alpha(2), possibly due to its lower hardness and higher thermal expansion coefficient, making it more prone to deformation under stress. This led to more extensive recrystallization in gamma than in alpha(2) during reheating, and cracks were more likely to initiate from the interior of alpha(2) or the gamma/alpha(2) interfaces, potentially due to incompatible deformation between the two phases.
3D PRINTING AND ADDITIVE MANUFACTURING
(2023)
Article
Materials Science, Multidisciplinary
Xintian Wang, Zhiyong Ji, Robert O. Ritchie, Ilya Okulov, Juergen Eckert, Chunlei Qiu
Summary: In this study, TiAl and Cr3C2 particles were added to a CrMnFeCoNi alloy to improve its processibility and mechanical properties. The addition of TiAl particles resulted in the formation of cracks, but the further addition of Cr3C2 particles helped suppress hot cracking. The presence of long-range ordered domains and precipitates contributed to the improved strength of the dual-particle containing alloy.
MATERIALS TODAY ADVANCES
(2023)
Article
Materials Science, Multidisciplinary
G. Y. Zhou, X. T. Wang, G. H. Cao, A. M. Russell, M. Luo, X. M. Dong, Z. H. Zhang
Summary: The sulfide stress cracking (SSC) behavior of API-5CT-C110 grade casing steel was evaluated using double cantilever beam (DCB) testing, and two thermal treatments were used to study the microstructures and properties. The study showed that the use of two short-term tempering treatments significantly decreased precipitate size and dislocation density compared to a single long-term tempering treatment. DCB testing demonstrated that double tempering improved SSC resistance without degradation of strength. Specimens treated with double tempering exhibited a lower proportion of sigma 3 boundary, high-angle grain boundaries, high Taylor factor values, and reduced susceptibility to crack initiation and propagation.
Article
Engineering, Manufacturing
Przemyslaw Golebiewski, Pawel Wienclaw, Jaroslaw Cimek, Pawel Socha, Dariusz Pysz, Adam Filipkowski, Grzegorz Stepniewski, Olga Czerwinska, Ireneusz Kujawa, Ryszard Stepien, Rafal Kasztelanic, Andrzej Burgs, Ryszard Buczynski
Summary: We report the development of a 3D printing process for producing soft glass optical fibers. The process involves direct printing using a miniaturized crucible and depositing straight horizontally-oriented lines to replace traditional assembly techniques. Experimental results demonstrate good performance of the printed photonic crystal fiber preform.
ADDITIVE MANUFACTURING
(2024)