Analysis of hierarchical microstructural evolution in electron beam powder bed fusion Ti–6Al–4V alloys via time-of-flight neutron diffraction

Mori, M.; Yamanaka, Kazushi; Onuki, Yusuke; Sato, Sadao; Chiba, Akihiko

doi:10.1016/j.addlet.2022.100053

Cited by 3 publications

(8 citation statements)

References 50 publications

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“…The post-processed specimens exhibited coarser acicular microstructures while maintaining α + β microstructures. A previous study [54] revealed that the volume fractions of the β-phase in the as-built, HIP, and HT specimens were 4.9, 7.4, and 9.0 vol.%, respectively, as determined via TOF-ND/RTA.…”

Section: Microstructuresmentioning

confidence: 81%

“…Ti-6Al-4V alloy samples that were employed in this study are similar to those used in previous studies [46,54,60]. Cylindrical specimens with a diameter of ϕ18 mm and height of 160 mm, where the longitudinal directions of the specimens were parallel to the building directions (BDs), were prepared using an Arcam A2X system with the standard raw powder and build parameters (Table 1) provided by the manufacturer.…”

Section: Sample Preparationmentioning

confidence: 99%

“…The iMATERIA beamline consists of three types of detector banks: backscattering (BS), special environment (SE), and low angle (LA), covering a wide range of scattering vectors. The ND datasets used in this study were obtained simultaneously with those used in the previous study [54].…”

Section: Neutron Diffraction Measurementsmentioning

confidence: 99%

“…Multiple reflections are successfully detected for each constituent phase; thus, the simultaneous determination of the dislocation density is possible for both the α-and β-phases. Neither post-processing method changes the phase constituents (i.e., α-and β-phases), although the β-phase fraction increases [54].…”

Section: Neutron Diffraction Patternsmentioning

confidence: 99%

“…The ND-based texture analysis was used to calibrate and validate the developed elasto-plastic crystal plasticity model. Recently, by combining time-of-flight ND (TOF-ND) measurements and Rietveld texture analysis (RTA) [53], the β-phase fraction in an EB-PBF Ti-6Al-4V alloy was precisely determined [54]. Furthermore, a hierarchal texture evolution between the prior β-phase, acicular α-matrix, and β-phase at the α-interfaces was observed.…”

Section: Introductionmentioning

confidence: 99%

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Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis

Yamanaka

Mori

Onuki

et al. 2022

Metals

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Ti–6Al–4V alloys undergo a multiple phase transformation sequence during electron beam powder bed fusion (EB-PBF) additive manufacturing, forming unique dislocation substructures. Thus, determining the dislocation density is crucial for comprehensively understanding the strengthening mechanisms and deformation behavior. This study performed time-of-flight neutron diffraction (TOF-ND) measurements of Ti–6Al–4V alloys prepared via EB-PBF and examined the dislocation density in the as-built and post-processed states using convolutional multiple whole profile (CMWP) fitting. The present TOF-ND/CMWP approach successfully determined the bulk-averaged dislocation density (6.8 × 1013 m−2) in the as-built state for the α-matrix, suggesting a non-negligible contribution of dislocation hardening. The obtained dislocation density values were comparable to those obtained by conventional and synchrotron X-ray diffraction (XRD) measurements, confirming the reliability of the analysis, and indicating that the dislocations in the α-matrix were homogeneously distributed throughout the as-built specimen. However, the negative and positive neutron scattering lengths of Ti and Al, respectively, lowered the diffraction intensity for the Ti−6Al−4V alloys, thereby decreasing the lower limit of the measurable dislocation density and making the analysis difficult.

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Section: Microstructuresmentioning

confidence: 81%

Section: Sample Preparationmentioning

confidence: 99%

Section: Neutron Diffraction Measurementsmentioning

confidence: 99%

Section: Neutron Diffraction Patternsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis

Yamanaka

Mori

Onuki

et al. 2022

Metals

Self Cite

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Neutron diffraction analysis of microstructural evolution and mechanical behavior in an additively manufactured multiphase alloy

Yamanaka,

Mori,

Onuki

et al. 2024

IOP Conf. Ser.: Mater. Sci. Eng.

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Additive manufacturing (AM) involves an unprecedented thermal history during solidification and post-melt high-temperature exposure, leading to unique microstructural evolution. In this study, we employed neutron-diffraction-based microstructural analysis to better understand the microstructural evolution and mechanical behavior of AM alloys, with a particular focus on multiphase alloys. Samples of Ti−6Al−4V alloy used as a model material were prepared using electron beam powder bed fusion (EB-PBF) under varying building conditions. Time-of-flight neutron diffraction (TOF-ND) measurements were performed using an iMATERIA (BL20), J-PARC, Japan. Using Rietveld texture analysis (RTA), we revealed the textural evolution during hierarchical microstructural development from solidification to solid-state phase transformations in the EB-PBF process. The effects of building conditions on the textures in the as-built states and their evolution during subsequent tensile loading were analyzed.

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Principal Preferred Orientation Evaluation of Steel Materials Using Time-of-Flight Neutron Diffraction

Xu,

Zhang,

Harjo

et al. 2024

QuBS

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Comprehensive information on in situ microstructural and crystallographic changes during the preparation/manufacturing processes of various materials is highly necessary to precisely control the microstructural morphology and the preferred orientation (or texture) characteristics for achieving an excellent strength–ductility–toughness balance in advanced engineering materials. In this study, in situ isothermal annealing experiments with cold-rolled 17Ni-0.2C (mass%) martensitic steel sheets were carried out by using the TAKUMI and ENGIN-X time-of-flight neutron diffractometers. The inverse pole figures based on full-profile refinement were extracted to roughly evaluate the preferred orientation features along three principal sample directions of the investigated steel sheets, using the General Structure Analysis System (GSAS) software with built-in generalized spherical harmonic functions. The consistent rolling direction (RD) inverse pole figures from TAKUMI and ENGIN-X confirmed that the time-of-flight neutron diffraction has high repeatability and statistical reliability, revealing that the principal preferred orientation evaluation of steel materials can be realized through 90° TD ➜ ND (transverse direction ➜ normal direction) rotation of the investigated specimen on the sample stage during two neutron diffraction experiments. Moreover, these RD, TD, and ND inverse pole figures before and after the in situ experiments were compared with the corresponding inverse pole figures recalculated from the MUSASI-L complete pole figure measurement and the HIPPO in situ microstructure evaluation, respectively. The similar orientation distribution characteristics suggested that the principal preferred orientation evaluation method can be applied to the in situ microstructural evolution of bulk orthorhombic materials and spatially resolved principal preferred orientation mappings of large engineering structure parts.

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Analysis of hierarchical microstructural evolution in electron beam powder bed fusion Ti–6Al–4V alloys via time-of-flight neutron diffraction

Cited by 3 publications

References 50 publications

Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis

Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis

Neutron diffraction analysis of microstructural evolution and mechanical behavior in an additively manufactured multiphase alloy

Principal Preferred Orientation Evaluation of Steel Materials Using Time-of-Flight Neutron Diffraction

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