Article
Nanoscience & Nanotechnology
Yingyue Yin, Jianhua Zhang, Jian Gao, Zhenhua Zhang, Quanquan Han, Zhuoliang Zan
Summary: Ni-based Hastelloy X (HX) superalloy is widely used in the aerospace industry for its excellent oxidation resistance and high-temperature strength. This study established statistical models for the effects of process parameters on density and surface roughness of LPBF-fabricated HX, and examined the interactions among density, surface roughness, and processing parameters. Experimental results showed that optimized parameters led to maximum density and minimum surface roughness, demonstrating the potential for customized performance in additive manufacturing of Ni-based parts.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Xinxin Liu, Rui Hu, Chenyu Yang, Xian Luo, Yanhao Hou, Jie Bai, Rui Ma
Summary: This study systematically investigated the microstructure and tensile properties of a composition-optimized Haynes 230 alloy fabricated by the LPBF method. It found that the unique cellular structure, characterized by solute Nb segregation and high-density dislocations, is the main reason for the remarkable mechanical properties of the alloy. The strengthening effects of the cellular structure, a combination of dislocation and elemental segregation strengthening, contribute significantly to the yield strength. In addition, the deformation incompatibility of heterogeneous grain and cellular structures leads to high hetero-deformation induced strengthening.
MATERIALS & DESIGN
(2023)
Article
Nanoscience & Nanotechnology
Shuya Zhang, Xin Lin, Lilin Wang, Xiaobin Yu, Yunlong Hu, Haiou Yang, Liming Lei, Weidong Huang
Summary: The microstructures and mechanical properties of Inconel 718 (IN718) alloy fabricated by selective laser melting (SLM) are evaluated under different conditions, with strengthening mechanisms including grain boundary, solid solution, precipitation, and dislocation strengthening. The strength is consistently higher in the horizontal direction than in the vertical direction, attributed to differences in dislocation density, effective grain size, and Taylor factor.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Xinxin Liu, Rui Hu, Chenyu Yang, Xian Luo, Jie Bai, Rui Ma
Summary: Recently,?' phase has been introduced into Haynes 230 alloy to improve its strength for better performance in harsh conditions. However, the precipitation of ?' phase was not observed under as-fabricated condition and the appearance of harmful Laves phases with high-W content was reported. In this study, the dissolution mechanisms of Laves phases and the strengthening mechanisms of ?' phase were investigated in a novel ?'-strengthening superalloy prepared by laser powder bed fusion. The results show that Laves phases continue to dissolve with increasing solution heat treatment temperature and are finally eliminated after heat treating at 1200 C-?. After aging heat treatment, nanosized ?' particles are precipitated, resulting in a combination of strength and ductility.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
I. Rodriguez-Barber, A. M. Fernandez-Blanco, I. Unanue-Arruti, I. Madariaga-Rodriguez, S. Milenkovic, M. T. Perez-Prado
Summary: The aim of this study is to determine the processability window of laser powder bed fusion (LPBF) for Inconel 939 (IN939) alloy using pulsed wave (PW) laser emission. A design of experiments strategy was employed to find the optimal laser power, scan speed, and hatch distance parameters. Different characterization techniques were used to analyze the microstructure of the samples, and mechanical tests were conducted to compare the performance of the additively manufactured specimens with cast samples. The study shows that IN939 can be processed by PW LPBF with high densities and a flexible microstructural design within the optimum processability window.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Chuan Guo, Zhuoyu Li, Yuhe Huang, Minglin He, Gan Li, Qingqing Li, Yang Zhou, Fan Zhou, Gang Ruan, Wangqing Wu, Qiang Zhu
Summary: Powder bed fusion using a laser beam is a promising additive manufacturing technology that enables the production of components with complex geometries and design freedom. By altering the microstructures of different layers through changes in processing parameters, it is possible to customize the material properties to meet various service conditions.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Nanoscience & Nanotechnology
Zhibo Hao, Tian Tian, Xinggang Li, Yuhe Huang, Shiqing Peng, Qiang Zhu, Changchun Ge
Summary: This study investigated the effects of heat treatment on the microstructure and mechanical properties of a nickel-based superalloy prepared by LPBF. The results showed that both HIP and HT processes improved the alloy's structure and properties, while an increase in HIP temperature led to grain refinement and elimination of some structural defects.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Xinxin Liu, Rui Hu, Xian Luo, Chenyu Yang, Xiangyu Gao
Summary: This study investigated the metallurgical defects, microstructure, and tensile properties of a novel Ni-Cr-W superalloy based on Haynes 230 alloy fabricated by laser powder bed fusion. The results showed excellent processability and mechanical properties of the alloy, with nearfully dense samples obtained under optimal conditions. The microstructure of the alloy exhibited multi-scale heterogeneous features, leading to its high ultimate tensile strength, yield strength, and ductility at room temperature.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
You Wang, Wei Guo, Hang Zheng, Yinkai Xie, Xuefeng Zhang, Huaixue Li, Ming Xu, Hongqiang Zhang
Summary: Nickel-based superalloy (Haynes 230) parts were fabricated using laser-based powder bed fusion, and crack defects were unavoidable. In order to understand the crack formation mechanism and eliminate the cracks, hot isostatic pressing method was employed. The results showed that the microstructure had cellular and columnar crystal structures in different directions, and the formation of solidification and liquation cracks was promoted by the precipitation of M23C6 carbides and NiSi eutectic phases at high angle grain boundaries. After hot isostatic pressing treatment, the cracks were eliminated, and the tensile properties were improved.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
R. J. Lancaster, S. J. Davies, S. P. Jeffs, D. T. S. Lewis, M. P. Coleman
Summary: The study found that exposure to service temperatures causes microstructural and chemical alterations in LPBF and cast C263 samples, directly affecting mechanical response. The thermal exposure program demonstrated that with the precipitation of carbide phases in the exposed LPBF variant, grain boundary morphologies are highly comparable to the wrought equivalent of the same alloy.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
S. Tao, R. Gao, H. Peng, H. Guo, B. Chen
Summary: This study demonstrates the successful repair of CMSX-4 single crystals using powder-bed fusion additive manufacturing technology, achieving a fine columnar dendritic substructure, limited in-grain misorientation, and strong deposit-to-substrate bonding.
MATERIALS & DESIGN
(2022)
Article
Materials Science, Multidisciplinary
Shengbin Dai, Jiangqi Zhu, Xingchen Yan, Shun Wu, Yang Liu, Xiang Gao, Hamish Fraser, Peter Hodgson, Yuman Zhu, Martin Heilmaier, Aijun Huang
Summary: This study successfully combines oxide dispersion strengthened nickel-based superalloys with the laser powder bed fusion process using electrostatic self-assembly. By adding yttria oxide, the alloy's room-temperature yield strength is significantly improved due to the combined effects of yttria dispersion strengthening and dislocation strengthening within a heterogeneous microstructure.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Materials Science, Multidisciplinary
Abdul Shaafi Shaikh, Fiona Schulz, Kevin Minet-Lallemand, Eduard Hryha
Summary: Ni-base superalloys like Haynes 282 can be successfully manufactured using laser-powder bed fusion with crack-free, full density results. While mechanical properties are superior to traditional materials, anisotropy is a concern, and high-temperature performance is promising. Ideal candidate for additive manufacturing if heat treatments can be optimized for as-built microstructure.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Zhongwei Yan, Vyacheslav Trofimov, Changhui Song, Changjun Han, Yongqiang Yang, Chao Yang, Yunmian Xiao, Zhengtai Deng, Jie Chen
Summary: The effect of ultrasonic vibration on surface roughness, relative density, and microstructure of ultrasonic vi-bration-assisted laser powder bed fusion (LPBF)-fabricated GH5188 superalloy were analyzed. The mechanical properties show improvement with ultrasonic vibration, including grain refinement, inhibition of texture preference orientation, and increased microhardness, tensile strength, yield strength, and elongation. The investigation demonstrates the feasibility of ultrasonic vibration to improve LPBF forming.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Hossein Eskandari Sabzi, Everth Hernandez-Nava, Xiao-Hui Li, Hanwei Fu, David San-Martin, Pedro E. J. Rivera-Diaz-del-Castillo
Summary: A new approach to modeling microstructure evolution and yield strength in laser powder bed fusion components was introduced, revealing the activation of various restoration mechanisms during the process. A mechanism for the formation of low-angle grain boundaries to enhance alloy strength was suggested, along with a validated equation based on subgrain size. The study quantitatively described the dependency of yield stress on process parameters and alloy composition.
MATERIALS & DESIGN
(2021)
Article
Materials Science, Multidisciplinary
Zhida Liang, Jonathan D. H. Paul, Andreas Stark, Andreas Bezold, Steffen Neumeier, Mathias Goeken, Florian Pyczak
Summary: Recent research has explored the Co-Al-W system and revealed interesting properties, but its high tungsten content limits industrial applications. As a result, new high temperature superalloys based on the Co-Ni-Al-Ti system, strengthened by chromium and different refractory elements, have been developed. These alloys exhibit better mechanical properties at high temperatures compared to conventional Ni-based superalloys and Co-based superalloys.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Luis Angel Morales, Andreas Bezold, Andreas Foerner, Hendrik Holz, Benoit Merle, Steffen Neumeier, Carolin Koerner, Christopher H. Zenk
Summary: Introducing Cu nanoparticles effectively strengthens and toughens Fe-based materials. This study investigates the effect of Cu on the mechanical properties of a novel Fe-based superalloy. Cu-containing alloy exhibits slightly higher strength, but heat treatment has a more significant impact. The presence of Cu also leads to a higher creep rate and faster-coarsening kinetics.
ADVANCED ENGINEERING MATERIALS
(2023)
Editorial Material
Materials Science, Multidisciplinary
Ramamoorthy Ramesh, Susmita Bose, Mathias Goeken, Sarah Morgan
JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
A. Bezold, L. P. Freund, A. Foerner, J. Voelkl, L-K Huber, M. Goeken, S. Neumeier
Summary: Recent researches have shown the excellent high-temperature properties of polycrystalline CoNi-base superalloys, but their deformation behavior has been rarely studied. This study investigated the deformation mechanisms of four polycrystalline CoNi-base superalloys with slightly different compositions. The results showed that the deformation mechanism changed with strain-rate and temperature, and the alloys with (Ta + Ti) exhibited a transition from shearing by APB-coupled dislocation pairs to stacking fault shearing and microtwinning. In contrast, APB-based shearing mechanisms were observed in both (Al + W)-rich alloys under all conditions.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
A. Kirchmayer, M. Weiser, P. Randelzhofer, L. P. Freund, B. Gehrmann, M. Hafez Haghighat, D. Huenert, M. Goeken, S. Neumeier
Summary: VDM (R) Alloy 780 is a new polycrystalline Ni-based superalloy with high Co, Cr, and Al contents designed for operation up to 750 degrees C. The alloy is strengthened by the precipitation of the gamma ' phase, which has been analyzed using atom probe tomography. Delta and eta phases are also present for grain boundary pinning, with the former forming plate-like or lamellar structures inside the latter. Compared to Udimet 720Li and A718Plus, VDM (R) Alloy 780 exhibits superior oxidation resistance at 800 degrees C and 900 degrees C, showing lower mass gain and thinner oxide layers. Transmission electron microscopy and scanning transmission electron microscopy investigations of the oxide scales reveal that the Al/Ti ratio plays a significant role in the oxidation behavior of these alloys.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Andreas Foerner, Jan Vollhueter, Anna Krapf, Abdullah Jamjoom, Daniel Hausmann, Benjamin Wahlmann, Zongwen Fu, Carolin Koerner, Steffen Neumeier, Mathias Goeken
Summary: By increasing the density of interfaces in NiAl-CrMo in situ composites through electron beam powder bed fusion (PBF-EB), a refined microstructure with an equiaxed or columnar cell morphology can be achieved. The mechanical properties at elevated temperatures are significantly improved compared to conventionally cast material, with the columnar morphology exhibiting the best performance at high temperatures and the equiaxial morphology showing nearly ideal isotropic mechanical behavior.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Chemistry, Physical
M. Koebrich, A. Foerner, N. Volz, C. H. Zenk, S. G. Fries, M. Goeken, S. Neumeier
Summary: The influence of various alloying elements on Co-Al-W based superalloys has been investigated, but the role of refractory and platinum group elements is still not fully understood. This study examines the microstructural changes and phase stability in Co9Al9W-X superalloys with different elements. Results show that adding refractory and platinum group elements preserves the gamma/gamma' microstructures but leads to the formation of additional intermetallic phases. The findings are compared with thermodynamic calculations and analyzed using different techniques. (c) 2023 Published by Elsevier B.V.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
A. Kirchmayer, M. Proebstle, D. Huenert, S. Neumeier, M. Goeken
Summary: Recently, the impact of orientation of eta/delta plates in Ni-base superalloys ATI 718Plus on fatigue crack propagation behavior was investigated. As the targeted alignment of eta/delta precipitates in complex components can be challenging, the effects of other microstructural features of ATI 718Plus were tested. It was found that increasing the eta/delta volume fraction, gamma' volume fraction, and precipitate size improved crack growth resistance but worsened creep properties. Conversely, increasing grain size enhanced creep properties and fatigue crack growth resistance. Compared to microstructures with strongly aligned eta/delta plates, the impact of the investigated microstructures on mechanical properties was smaller. These findings provide insights for designing desired microstructures based on specific application requirements for crack propagation and creep resistance.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
J. Vollhueter, A. Bezold, N. Karpstein, M. Koebrich, E. Spiecker, M. Goeken, S. Neumeier
Summary: The deformation mechanisms in superalloys depend on parameters such as composition, temperature, and strain rate. This study investigated the change in deformation mechanism from shearing by APB-coupled dislocations to shearing under the formation of stacking faults as a function of strain rate. The results showed that the deformation mechanism transition is influenced by strain rate, with higher stacking fault density associated with lower strain rates and higher yield strength.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
A. Bezold, S. Neumeier
Summary: The significance of segregation processes during high temperature deformation in superalloys has become increasingly evident in recent years. Here, the importance of additionally tailoring the active deformation mechanisms is shown by correlating the strain-rate dependent high temperature strength of two slightly different polycrystalline CoNi-base superalloys with their underlying defect structures. Transmission electron microscopy investigations revealed that at high strain-rates shearing by APB-coupled dislocation pairs occurs in both alloys. With decreasing strain-rate, the deformation mechanism in one alloy transitions to stacking fault shearing and at very low strain-rates also to microtwinning, while APB-based shearing remains dominant in the other alloy. In comparison, stacking fault shearing induced a relative increase in strength of 200 MPa, which is diminished to 100 MPa as microtwinning becomes more prevalent implying that the high temperature strength of this alloy system can be significantly increased by tailoring the acting deformation mechanism.
SCRIPTA MATERIALIA
(2023)
