scholarly journals Characterising the Microstructure of an Additively Built Al-Cu-Li Alloy

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5188
Author(s):  
Iris Raffeis ◽  
Frank Adjei-Kyeremeh ◽  
Uwe Vroomen ◽  
Silvia Richter ◽  
Andreas Bührig-Polaczek
Keyword(s):  
Volume Fraction ◽  
Analytical Techniques ◽  
High Strength ◽  
High Energy ◽  
Phase System ◽  
X Ray Diffraction ◽  
Powder Bed ◽  
X Ray ◽  
Conventional View ◽  
Multi Phase

Al-Cu-Li alloys are famous for their high strength, ductility and weight-saving properties, and have for many years been the aerospace alloy of choice. Depending on the alloy composition, this multi-phase system may give rise to several phases, including the major strengthening T1 (Al2CuLi) phase. Microstructure investigations have extensively been reported for conventionally processed alloys with little focus on their Additive Manufacturing (AM) characterised microstructures. In this work, the Laser Powder Bed Fusion (LPBF) built microstructures of an AA2099 Al-Cu-Li alloy are characterised in the as-built (no preheating) and preheat-treated (320 °C, 500 °C) conditions using various analytical techniques, including Synchrotron High-Energy X-ray Diffraction (S-HEXRD). The observed dislocations in the AM as-built condition with no detected T1 precipitates confirm the conventional view of the difficulty of T1 to nucleate on dislocations without appropriate heat treatments. Two main phases, T1 (Al2CuLi) and TB (Al7.5Cu4Li), were detected using S-HEXRD at both preheat-treated temperatures. Higher volume fraction of T1 measured in the 500 °C (75.2 HV0.1) sample resulted in a higher microhardness compared to the 320 °C (58.7 HV0.1) sample. Higher TB volume fraction measured in the 320 °C sample had a minimal strength effect.

scholarly journals Strain-Ageing of Low-Alloyed Multiphase High-Strength Steels

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 439 ◽  
Author(s):  
Ludovic Samek ◽  
Jakub Dykas ◽  
Emmanuel De Moor ◽  
Adam Grajcar
Keyword(s):  
Strain Aging ◽  
Volume Fraction ◽  
High Strength Steels ◽  
High Strength ◽  
X Ray Diffraction ◽  
X Ray ◽  
Static Strain ◽  
Static Strain Aging ◽  
Thin Foils ◽  
Long Time

The strain-aging of low alloyed, multiphase high-strength steels with strain-induced austenite to martensite transformation was studied. The influence of prestrain, aging time, and temperature dependence of the static strain aging was carried out. Ageing temperatures between 60 and 220 ∘ C and aging times from 20 to 10,000 min were investigated. The choice of steel composition allowed studying the influence of alloying elements, such as Si and Al, on the static strain aging behavior. Samples after aging were studied using light-optical microscopy, X-ray diffraction, and in-depth transmission electron microscopy (TEM). The Harper model was used to describe the precipitation mechanisms occurring during aging. The study of thin foils after aging using TEM showed the precipitation of low temperature transition carbides in the microstructure, which was observed between 60 and 5000 min. By using X-ray diffraction, it was revealed that aging at 170 ∘ C for a long time caused a slight decrease of the retained austenite volume fraction, but the C content remained constant.

Synthesis and characterization of Co–B–Fe–Ti nanosized alloyed powders

2021 ◽  
Vol 112 (1) ◽  
pp. 35-41
Author(s):  
Hasan Eskalen ◽  
Mikail Aslan ◽  
Hakan Yaykaşlı ◽  
Musa Gögebakan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Solid Solution ◽  
Analytical Techniques ◽  
High Energy ◽  
Nanocrystalline Phase ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ball Milling Technique

Abstract In this study, novel Co60Fe18Ti18B4 alloy powders have been synthesized with high compositional homogeneity using a high-energy ball milling technique. The structural, morphological and mechanical properties of the nanosized alloyed powders were examined using different analytical techniques, including scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry and X-ray diffraction. According to the X-ray diffraction analysis for both Co powder and Co60Fe18Ti18B4 alloy powders, with increasing milling time, the content of Co-based (hcp) solid solution decreased and Co-based (fcc) solid solution increased. The mechanical properties of the material were also investigated by Vickers micro-hardness testing. The micro-hardness value of the Co60Fe18Ti18B4 alloy was found as 120.08 HV. After sintering (1 h– 1000 °C), the hardness improved remarkably (536.32 HV). Furthermore, results indicate that the synthesized Co-based alloy powder has both glassy and nanocrystalline phase forms.

Deformation Mechanisms of Twinning-Induced Plasticity Steel Under Shock-Load: Investigated by Synchrotron X-Ray Diffraction

2019 ◽  
Vol 3 (3) ◽  
pp. 15
Author(s):  
Kun Yan ◽  
Mark Callaghan ◽  
Klaus-Dieter Liss
Keyword(s):  
High Strength ◽  
Orientation Distribution ◽  
High Energy ◽  
Mechanical Twinning ◽  
Deformation Mechanisms ◽  
Strain Rates ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compression Direction ◽  
Twip Steels

As an ideal candidate material for automobiles, twinning-induced plasticity (TWIP) steels possess excellent formability, high strength and high energy absorption ability during collision. This is attributed to its deformation mechanism of mechanical twinning, resulting in a high work hardening rate. In the current study, deformation mechanisms of low-stacking fault energy TWIP steel, under different strain rates between 0.01/s to 1581/s, were investigated by high-energy X-ray diffraction. After compression, grains with {110}||compression direction became favourable. Higher intensity was observed near brass and A components in the selected orientation distribution function (ODF) section (φ2 = 45°) for all the compressed specimens. The activity of twinning was found to be the highest in the specimens that had been compressed with medium–high strain rates (e.g., 100/s and 10/s), while the texture component related to slip had stronger intensity in the specimen deformed with a quasi-static strain rate (0.01/s).

scholarly journals A laser powder bed fusion system for in situ x-ray diffraction with high-energy synchrotron radiation

2020 ◽  
Vol 91 (7) ◽  
pp. 075104
Author(s):  
Eckart Uhlmann ◽  
Erwin Krohmer ◽  
Felix Schmeiser ◽  
Norbert Schell ◽  
Walter Reimers
Keyword(s):  
Synchrotron Radiation ◽  
High Energy ◽  
Fusion System ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
X Ray Diffraction ◽  
Powder Bed ◽  
X Ray

Multi length scale characterization of austenite in TRIP steels using high-energy X-ray diffraction

2013 ◽  
Vol 28 (2) ◽  
pp. 77-80 ◽  
Author(s):  
R. Blondé ◽  
E. Jimenez-Melero ◽  
L. Zhao ◽  
J.P. Wright ◽  
E. Brück ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Tensile Tests ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trip Steels ◽  
Stable Austenite ◽  
Scale Characterization ◽  
The Stability

The martensitic transformation behavior of the meta-stable austenite phase in low alloyed TRIP steels has been studied in situ using high-energy X-ray diffraction during deformation. The stability of austenite has been studied at different length scales during tensile tests and at variable temperatures down to 153 K. A powder diffraction analysis has been performed to correlate the macroscopic behavior of the material to the observed changes in the volume fraction of the phases. Our results show that at lower temperatures the deformation induced austenite transformation is significantly enhanced and extends over a wider deformation range, resulting in a higher elongation at fracture. To monitor the austenite behavior at the level of an individual grain a high-resolution far-field detector was used. Sub-grains have been observed in austenite prior to transformation.

Effect of Heat Treating on Precipitate Phases in NiTiHf

2015 ◽  
Author(s):  
Matthew Carl ◽  
Victoria Garcia ◽  
Brian Van Doren ◽  
Scott Schlegel ◽  
Marcus Young
Keyword(s):  
Martensitic Transformation ◽  
Analytical Techniques ◽  
Aging Effect ◽  
Heat Treating ◽  
High Energy ◽  
Rolled Plate ◽  
Material Strength ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated

Recently, NiTiHf-based HTSMAs have been shown to exhibit unique precipitation and mechanical behavior. In this study, a rolled plate of NiTiHf HTSMA was homogenized and heat treated at various times and temperatures and characterized using a barrage of analytical techniques including high-energy synchrotron X-ray diffraction (SR-XRD). Neither homogenization nor any of heat treatments studied significantly affect the austenitic or martensitic transformation temperatures. H-phase was observed to precipitate at heat treating times below 30 minutes and then to subsequently dissolve away for times of 30 minutes and above. The presence of H-phase dramatically increases the material strength by almost a factor of 2, Lastly, an over-aging effect occurs with increasing time due to the disappearance of the H-phase.

scholarly journals In Situ Determination of Phase Stress States in an Unstable Medium Manganese Duplex Steel Studied by High-Energy X-ray Diffraction

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1335
Author(s):  
Mathias Lamari ◽  
Sébastien Y. P. Allain ◽  
Guillaume Geandier ◽  
Jean-Christophe Hell ◽  
Astrid Perlade ◽  
...  
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
High Energy ◽  
Internal Stresses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Advanced High Strength Steels ◽  
Stress States

Duplex medium Mn steels are high-potential advanced high-strength steels (AHSS) for automotive construction. Their excellent forming properties stem from the specific stress partitioning between their constituting phases during deformation, namely the ferritic matrix, unstable retained austenite, and strain-induced fresh martensite. The stability of the retained austenite and the 3D stress tensors of each phase are determined simultaneously in this work by in situ high energy X-ray diffraction on synchrotron beamline during a tensile test. The role of internal stresses inherited from the manufacturing stage are highlighted for the first time as well as new insights to understand the origin of the serrations shown by these alloys.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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