liu.seSök publikationer i DiVA
Ändra sökning
Länk till posten
Permanent länk

Direktlänk
Peng, Ru Lin
Alternativa namn
Publikationer (10 of 196) Visa alla publikationer
Cui, L., Yu, C.-H., Jiang, S., Sun, X., Peng, R. L., Lundgren, J.-E. & Moverare, J. (2022). A new approach for determining GND and SSD densities based on indentation size effect: An application to additive-manufactured Hastelloy X. Journal of Materials Science & Technology, 96, 295-307
Öppna denna publikation i ny flik eller fönster >>A new approach for determining GND and SSD densities based on indentation size effect: An application to additive-manufactured Hastelloy X
Visa övriga...
2022 (Engelska)Ingår i: Journal of Materials Science & Technology, ISSN 1005-0302, Vol. 96, s. 295-307Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Dislocation plays a crucial role in controlling the strength and plasticity of bulk materials. However, determining the densities of geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) is one of the classical problems in material research for several decades. Here, we proposed a new approach based on indentation size effect (ISE) and strengthening theories. This approach was performed on a laser powder bed fused (L-PBF) Hastelloy X (HX), and the results were verified by the Hough-based EBSD and modified Williamson–Hall (m-WH) methods. Furthermore, to better understand the new approach and essential mechanisms, an in-depth investigation of the microstructure was conducted. The distribution of dislocations shows a clear grain orientation-dependent: low density in large <101> preferentially orientated grains while high density in fine <001> orientated grains. The increment of strengthening in L-PBF HX is attributed to a huge amount of edge-GNDs. Planar slip is the main operative deformation mechanism during indentation tests, and the slip step patterns depend mostly on grain orientations and stacking fault energy. This study provides quantitative results of GND and SSD density for L-PBF HX, which constructs a firm basis for future quantitative work on other metals with different crystal structures.

Ort, förlag, år, upplaga, sidor
Elsevier, 2022
Nyckelord
Microstructure characterization, Indentation size effect, Hastelloy X, Geometrically necessary dislocation, Statistically stored dislocation
Nationell ämneskategori
Teknisk mekanik
Identifikatorer
urn:nbn:se:liu:diva-177714 (URN)10.1016/j.jmst.2021.05.005 (DOI)
Anmärkning

Funding agencies: The Swedish Governmental Agency for Innovation Systems (Vinnova Grant No. 2016-05175) and the Center for Additive Manufacturing-metal (CAM2). Siemens Energy is acknowledged for providing the samples.

Tillgänglig från: 2021-07-01 Skapad: 2021-07-01 Senast uppdaterad: 2023-12-28
Yu, C.-H., Peng, R. L., Lee, T. L., Luzin, V., Lundgren, J.-E. & Moverare, J. (2022). Anisotropic behaviours of LPBF Hastelloy X under slow strain rate tensile testing at elevated temperature. Materials Science & Engineering: A, 844, Article ID 143174.
Öppna denna publikation i ny flik eller fönster >>Anisotropic behaviours of LPBF Hastelloy X under slow strain rate tensile testing at elevated temperature
Visa övriga...
2022 (Engelska)Ingår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 844, artikel-id 143174Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

To improve the understanding of high temperature mechanical behaviours of LPBF Ni-based superalloys, this work investigates the influence of an elongated grain structure and characteristic crystallographic texture on the anisotropic tensile behaviours in LPBF Hastelloy X (HX) at 700 °C. Two types of loading conditions have been examined to analyse the anisotropy related to the building direction (BD), including the vertical loading (loading direction//BD) and the horizontal loading (loading direction ⊥ BD). To probe the short-term creep behaviours, slow strain rate tensile testing (SSRT) has been applied to address the strain rate dependent inelastic strain accumulation. In-situ time-of-flight neutron diffraction upon loading was performed to track the anisotropic lattice strain evolution in the elastic region and the texture evolution in the plastic region. Combined with the post microstructure and fracture analysis, the anisotropic mechanical behaviours are well correlated with the different microstructural responses between vertical and horizontal loading and the different strain rates. A better creep performance is expected in the vertical direction with the consideration of the better ductility and the higher level of texture evolution.

Ort, förlag, år, upplaga, sidor
ELSEVIER SCIENCE SA, 2022
Nyckelord
Creep, Slow strain rate tensile testing (SSRT), Time-of-flight neutron diffraction, Texture, Ductility, Elastic constants
Nationell ämneskategori
Teknisk mekanik
Identifikatorer
urn:nbn:se:liu:diva-184826 (URN)10.1016/j.msea.2022.143174 (DOI)000797873300002 ()
Anmärkning

Funding agencies: Swedish Governmental Agency for Innovation Systems (Vinnova) [2016-05175]; AFM at Linkoping University; Centre for Additive Manufacturing-metal (CAM2); Science and Technology Facilities Council [2016-05175];  [2009-00971];  [RB2010043]

Tillgänglig från: 2022-05-09 Skapad: 2022-05-09 Senast uppdaterad: 2022-06-08
Cui, L., Deng, D., Jiang, F., Peng, R. L., Xin, T., Mousavian, R. T., . . . Moverare, J. (2022). Superior low cycle fatigue property from cell structures in additively manufactured 316L stainless steel. Journal of Materials Science & Technology, 111, 268-278
Öppna denna publikation i ny flik eller fönster >>Superior low cycle fatigue property from cell structures in additively manufactured 316L stainless steel
Visa övriga...
2022 (Engelska)Ingår i: Journal of Materials Science & Technology, ISSN 1005-0302, Vol. 111, s. 268-278Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

We have investigated the low cycle fatigue (LCF) properties and the extent of strengthening in a dense additively manufactured stainless steel containing different volume fractions of cell structures but having all other microstructure characteristics the same. The samples were produced by laser powder bed fusion (L-PBF), and the concentration of cell structures was varied systematically by varying the annealing treatments. Load-controlled fatigue experiments performed on samples with a high fraction of cell structures reveal an up to 23 times increase in fatigue life compared to an essentially cell-free sample of the same grain configuration. Multiscale electron microscopy characterizations reveal that the cell structures serve as the soft barriers to the dislocation propagation and the partials are the main carrier for cyclic loading. The cell structures, stabilized by the segregated atoms and misorientation between the adjacent cells, are retained during the entire plastic deformation, hence, can continuously interact with dislocations, promote the formation of nanotwins, and provide massive 3D network obstacles to the dislocation motion. The compositional micro-segregation caused by the cellular solidification features serves as another non-negligible strengthening mechanism to dislocation motion. Specifically, the cell structures with a high density of dislocation debris also appear to act as dislocation nucleation sites, very much like coherent twin boundaries. This work indicates the potential of additive manufacturing to design energy absorbent alloys with high performance by tailoring the microstructure through the printing process.

Ort, förlag, år, upplaga, sidor
Amsterdam, Netherlands: Elsevier, 2022
Nyckelord
Additive manufacturing, 316L stainless steel, fatigue behavior, cellular structure, nanotwins
Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:liu:diva-182257 (URN)10.1016/j.jmst.2021.10.006 (DOI)000788811500007 ()2-s2.0-85120774264 (Scopus ID)
Anmärkning

Funding: Swedish Governmental Agency for Innovation Systems (Vinnova) [2016-05175]; Science Foundation Ireland (SFI) [16/RC/3872]; Center for Additive Manufacturing-metal (CAM2); Ji Hua Laboratory [X210141TL210]

Tillgänglig från: 2022-01-11 Skapad: 2022-01-11 Senast uppdaterad: 2022-05-16Bibliografiskt granskad
Barriga, H., Cárdenas, M., Hall, S., Hellsing, M., Karlsson, M., Pavan, A., . . . Wolff, M. (2021). A Bibliometric Study on Swedish Neutron Users for the Period 2006–2020. Neutron News, 32(4), 28-33
Öppna denna publikation i ny flik eller fönster >>A Bibliometric Study on Swedish Neutron Users for the Period 2006–2020
Visa övriga...
2021 (Engelska)Ingår i: Neutron News, ISSN 1044-8632, E-ISSN 1931-7352, Vol. 32, nr 4, s. 28-33Artikel i tidskrift (Refereegranskat) Published
Ort, förlag, år, upplaga, sidor
Taylor & Francis, 2021
Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:liu:diva-182982 (URN)10.1080/10448632.2021.1999147 (DOI)
Tillgänglig från: 2022-02-16 Skapad: 2022-02-16 Senast uppdaterad: 2022-03-10Bibliografiskt granskad
Cui, L., Jiang, F., Deng, D., Xin, T., Sun, X., Mousavian, R. T., . . . Moverare, J. (2021). Cyclic Response of Additive Manufactured 316L Stainless Steel: The Role of Cell Structures. Scripta Materialia, 205, Article ID 114190.
Öppna denna publikation i ny flik eller fönster >>Cyclic Response of Additive Manufactured 316L Stainless Steel: The Role of Cell Structures
Visa övriga...
2021 (Engelska)Ingår i: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 205, artikel-id 114190Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

We report the effect of cell structures on the fatigue behavior of additively manufactured (AM) 316L stainless steel (316LSS). Compared with the cell-free samples, the fatigue process of fully cellular samples only consists of steady and overload stages, without an initial softening stage. Moreover, the fully cellular sample possesses higher strength, lower cyclic softening rate and longer lifetime. Microscopic analyses show no difference in grain orientations, dimensions, and shapes. However, the fully cellular samples show planar dislocation structures, whereas the cell-free samples display wavy dislocation structures. The existence of cell structures promotes the activation of planar slip, delays strain localization, and ultimately enhances the fatigue performance of AM 316LSS.

Ort, förlag, år, upplaga, sidor
Elsevier, 2021
Nyckelord
Additive manufacturing; 316L, stainless steel, Cellular structure, Cyclic response behavior, Deformation mechanism
Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:liu:diva-178237 (URN)10.1016/j.scriptamat.2021.114190 (DOI)000692550000002 ()2-s2.0-85112531684 (Scopus ID)
Anmärkning

Funding: Swedish Governmental Agency for Innovation Systems (Vinnova)Vinnova [2016-05175]; Science Foundation Ireland (SFI)Science Foundation Ireland [16/RC/3872]; European Regional Development FundEuropean Commission; I-Form industry partners; Ji Hua Laboratroy [X210141TL210]; Center for Additive Manufacturing-metal (CAM2)

Tillgänglig från: 2021-08-16 Skapad: 2021-08-16 Senast uppdaterad: 2023-12-28Bibliografiskt granskad
Xu, J., Schultz, F., Peng, R. L., Hryha, E. & Moverare, J. (2021). Effect of heat treatment on the microstructure characteristics and microhardness of a novel γ′ nickel-based superalloy by laser powder bed fusion. Result in Materials, 12, Article ID 100232.
Öppna denna publikation i ny flik eller fönster >>Effect of heat treatment on the microstructure characteristics and microhardness of a novel γ′ nickel-based superalloy by laser powder bed fusion
Visa övriga...
2021 (Engelska)Ingår i: Result in Materials, ISSN 2590-048X, Vol. 12, artikel-id 100232Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The fabrication of gamma prime (γ′) strengthened nickel-based superalloys by additive manufacturing (AM) techniques is of huge interest from the industrial and research community owing to their excellent high-temperature properties. The effect of post-AM-processing heat treatment on the microstructural characteristics and microhardness response of a laser powder bed fused (LPBF) γ′ strengthened nickel-based superalloy, MAD542, is systematically investigated. Post-processing heat treatment shows the significant importance of tailoring the γ′ morphology. With insufficient solutioning duration time, coarse γ′ formed in the interdendritic region heterogeneously, due to the lack of chemical composition homogenization. The cooling rate from the super-solvus solutioning plays an important role in controlling the γ′ size and morphology. Spherical γ′ is formed during the air cooling while irregularly shaped γ′ formed during the furnace cooling. The following aging heat treatment further tunes the γ′ morphology and γ channel width. After two-step aging, cuboidal γ′ is developed in the air-cooled sample, while in contrast, bi-modally distributed γ′ is developed in the furnace cooled sample with fine spherical γ′ embedded in the wide γ channel between coarse irregular shaped secondary γ′. More than 90% of the grains recrystallized during solutioning treatment at the super-solvus temperature for 30 min. The rapid recrystallization kinetics are attributed to the formation of annealing twins which significantly reduced the stored energy. Microhardness responses from different heat-treated conditions were examined.

Ort, förlag, år, upplaga, sidor
Elsevier, 2021
Nyckelord
Nickel-based superalloy; LPBF, Heat treatment, Gamma prime, Recrystallization
Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:liu:diva-181233 (URN)10.1016/j.rinma.2021.100232 (DOI)
Tillgänglig från: 2021-11-23 Skapad: 2021-11-23 Senast uppdaterad: 2021-12-14Bibliografiskt granskad
Xu, J., Ma, T., Peng, R. L. & Hosseini, S. (2021). Effect of post-processes on the microstructure and mechanical properties of laser powder bed fused IN718 superalloy. Additive Manufacturing, 48, Article ID 102416.
Öppna denna publikation i ny flik eller fönster >>Effect of post-processes on the microstructure and mechanical properties of laser powder bed fused IN718 superalloy
2021 (Engelska)Ingår i: Additive Manufacturing, ISSN 2214-8604, E-ISSN 2214-7810, Vol. 48, artikel-id 102416Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The post-processing on the additively manufactured component is of huge interest as the key to tailor the microstructure to obtain certain mechanical properties. In this present study, the effects of hot isostatic pressing, as well as heat treatment on the microstructure, phase configuration and mechanical properties of laser powder bed fused (LPBF) IN718 superalloy were systematically investigated. Three different post-processes were studied such as hot isostatic pressing (HIP), heat treatment (HT), and HIP followed by HT (HIP+HT). The HIP process effectively eliminated the Laves phase remained in the as-built microstructure and brought uniformly distributed super fine γ″ precipitates in nano-meter size. In the heat-treated microstructure, larger γ″ precipitates were promoted directly from the as-built material. In comparison the HIP+HT process caused a moderate growth of γ″. In the latter two cases, the developed γ″ significantly strengthened the material. Yield strength of IN718 was increased from 738 MPa in as-built condition to 1015 MPa and 1184 MPa after HT and HIP+HT, respectively. On the contrary the ductility in the as-built IN718 condition was reduced by more than 40% after HT and HIP+HT. This can be compared to an increase in the ductility by almost 30% when subjected the as-built specimens to only HIPping. Finally, the correlation between microstructure evolution and mechanical properties is discussed in detail.

Ort, förlag, år, upplaga, sidor
Elsevier, 2021
Nyckelord
Industrial and Manufacturing Engineering, Engineering (miscellaneous), General Materials Science, Biomedical Engineering
Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:liu:diva-181235 (URN)10.1016/j.addma.2021.102416 (DOI)000719343700003 ()2-s2.0-85117883933 (Scopus ID)
Forskningsfinansiär
Vinnova
Anmärkning

Funding: RISE IVF AB; Lighter Academy [Vinnova 2017-05200]

Tillgänglig från: 2021-11-23 Skapad: 2021-11-23 Senast uppdaterad: 2021-12-15Bibliografiskt granskad
Deng, D., Peng, R. L. & Moverare, J. (2021). High Temperature Mechanical Integrity of Selective Laser Melted Alloy 718 Evaluated by Slow Strain Rate Tests. International journal of plasticity, 140, Article ID 102974.
Öppna denna publikation i ny flik eller fönster >>High Temperature Mechanical Integrity of Selective Laser Melted Alloy 718 Evaluated by Slow Strain Rate Tests
2021 (Engelska)Ingår i: International journal of plasticity, ISSN 0749-6419, E-ISSN 1879-2154, Vol. 140, artikel-id 102974Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Strain rate dependent deformation behaviours of selective laser melted Alloy 718 (IN718) are systematically studied at 550 and 650 °C by slow strain rate testing, with a forged counterpart as a reference. Selective laser melted IN718 shows significant susceptibility to intergranular cavitation, resulting in ductility degradation with decreasing strain rate. Detailed fractography and cross section inspections are employed to identify the damage mechanisms. Creep rates are also estimated and compared with the conventional counterparts. The possible critical factors for the inferiority of time dependent damage resistance of selective laser melted IN718 are discussed.

Ort, förlag, år, upplaga, sidor
Elsevier, 2021
Nyckelord
IN718; Selective laser melting (SLM); Creep; Environment-assisted grain boundary embrittlement; Slow strain rate test; Cavitation; Surface energy
Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:liu:diva-174589 (URN)10.1016/j.ijplas.2021.102974 (DOI)000647434800002 ()
Anmärkning

Funding: Faculty grant SFOMATLiU from Linkoping University [200900971]; Swedish Governmental Agency for Innovation Systems (Vinnova)Vinnova [2016-05175]

Tillgänglig från: 2021-03-25 Skapad: 2021-03-25 Senast uppdaterad: 2021-05-26Bibliografiskt granskad
Cui, L., Jiang, S., Xu, J., Peng, R. L., Mousavian, R. T. & Moverare, J. (2021). Revealing Relationships between Microstructure and Hardening Nature of Additively Manufactured 316L Stainless Steel. Materials & Design, 198, Article ID 109385.
Öppna denna publikation i ny flik eller fönster >>Revealing Relationships between Microstructure and Hardening Nature of Additively Manufactured 316L Stainless Steel
Visa övriga...
2021 (Engelska)Ingår i: Materials & Design, ISSN 0261-3069, Vol. 198, artikel-id 109385Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Relationships between microstructures and hardening nature of laser powder bed fused (L-PBF) 316 L stainless steel have been studied. Using integrated experimental efforts and calculations, the evolution of microstructure entities such as dislocation density, organization, cellular structure and recrystallization behaviors were characterized as a function of heat treatments. Furthermore, the evolution of dislocation-type, namely the geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs), and their impacts on the hardness variation during annealing treatments for L-PBF alloy were experimentally investigated. The GND and SSD densities were statistically measured utilizing the Hough-based EBSD method and Taylor's hardening model. With the progress of recovery, the GNDs migrate from cellular walls to more energetically-favourable regions, resulting in the higher concentration of GNDs along subgrain boundaries. The SSD density decreases faster than the GND density during heat treatments, because the SSD density is more sensitive to the release of thermal distortions formed in printing. In all annealing conditions, the dislocations contribute to more than 50% of the hardness, and over 85.8% of the total dislocations are GNDs, while changes of other strengthening mechanism contributions are negligible, which draws a conclusion that the hardness of the present L-PBF alloy is governed predominantly by GNDs.

Ort, förlag, år, upplaga, sidor
Elsevier, 2021
Nyckelord
Laser powder bed fusion; 316L stainless steel; Dislocation-type; Hardening nature; Microstructural evolution
Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:liu:diva-171912 (URN)10.1016/j.matdes.2020.109385 (DOI)000699974700012 ()2-s2.0-85097346061 (Scopus ID)
Anmärkning

Funding: Swedish Governmental Agency for Innovation Systems (Vinnova)Vinnova [2016-05175]; Science Foundation Ireland (SFI)Science Foundation Ireland [16/RC/3872]; Center for Additive Manufacturing-metal (CAM2); European Regional Development FundEuropean Commission

Tillgänglig från: 2020-12-14 Skapad: 2020-12-14 Senast uppdaterad: 2023-12-28Bibliografiskt granskad
Yu, C.-H., Peng, R. L., Calmunger, M., Luzin, V., Brodin, H. & Moverare, J. (2020). Anisotropic Deformation and Fracture Mechanisms of an Additively Manufactured Ni-Based Superalloy. In: Tin, Sammy; Hardy, Mark; Clews, Justin; Cormier, Jonathan; Feng, Qiang; Marcin, John; O'Brien, Chris; Suzuki, Akane (Ed.), Superalloys 2020: . Paper presented at Cham (pp. 1003-1013). Springer International Publishing
Öppna denna publikation i ny flik eller fönster >>Anisotropic Deformation and Fracture Mechanisms of an Additively Manufactured Ni-Based Superalloy
Visa övriga...
2020 (Engelska)Ingår i: Superalloys 2020 / [ed] Tin, Sammy; Hardy, Mark; Clews, Justin; Cormier, Jonathan; Feng, Qiang; Marcin, John; O'Brien, Chris; Suzuki, Akane, Springer International Publishing , 2020, s. 1003-1013Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

This study investigates the anisotropic mechanical and microstructural behavior of the laser powder bed fusionLaser powder bed fusion (LPBF) manufactured Ni-based superalloy Hastelloy X (HX) by using slow strain rate (10−5 and 10−6s−1) tensile testing (SSRT) at 700 °C. LPBF HX typically exhibits an elongated grain structure along the building direction (BD) and the texture analysis from the combination of neutron diffractionNeutron diffraction and EBSD discloses a major texture component <011> and a minor texture component <001> along BD, and a texture component <001> in the other two sample directions perpendicular to BD. Two types of tests have been performed, the horizontal tests where the loading direction (LD) is applied perpendicular to BD, and the vertical tests where LD is applied parallel to BD. The vertical tests exhibit lower strength but better ductility, which is explained by the texture effect and the elongated grain structure. A comparison of the mechanical behavior to the wrought HX shows that LPBF HX has better yield strength due to the high dislocation density as proved by TEM images. Creep voids are observed at grain boundaries in SSRT for both directions and are responsible for the poor ductility of the horizontal tests. The vertical ductility in SSRT maintains the same level as the reference tensile test at the strain rate of 10−3s−1, due to the extra deformation capacity contributed by the discovered deformation twinningDeformation twinning and lattice rotation. The deformation twinningDeformation twinning, which is only observed in the vertical tests and has not been found in the conventionally manufactured HX, is beneficial to maintain the ductility but does not strengthen the material.

Ort, förlag, år, upplaga, sidor
Springer International Publishing, 2020
Nyckelord
Laser powder bed fusion, Slow strain rate tensile testing, Deformation twinning, Texture evolution, Neutron diffraction
Nationell ämneskategori
Geoteknik
Identifikatorer
urn:nbn:se:liu:diva-169053 (URN)10.1007/978-3-030-51834-9_98 (DOI)
Konferens
Cham
Tillgänglig från: 2020-09-07 Skapad: 2020-09-07 Senast uppdaterad: 2022-05-06Bibliografiskt granskad
Organisationer

Sök vidare i DiVA

Visa alla publikationer