Crystal chemistry of clinker relicts from aged cementitious materials

2014 ◽  
Vol 47 (5) ◽  
pp. 1626-1637 ◽  
Author(s):  
Michele Secco ◽  
Luca Peruzzo ◽  
Laurie Palasse ◽  
Gilberto Artioli ◽  
Alberto Viani ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Chemical Properties ◽  
Cementitious Materials ◽  
Operating Conditions ◽  
General Tendency ◽  
Hydration Kinetics ◽  
Definition Of ◽  
Backscatter Diffraction

Despite the general tendency to consider Portland cement virtually fully hydrated within a few years, the occurrence of non-reacted clinker phases in cementitious materials that are several decades old is rather common. In this work, the integration of microstructural analysis by scanning electron microscopy and quantitative microchemical and micromineralogical characterization techniques, such as electron microprobe analysis and electron backscatter diffraction, allowed the definition of the crystal-chemical properties of partially hydrated cement residuals within different types of aged cementitious materials. The results on several clinker relicts show that the calcium silicate phases are transformed systematically and pervasively by hydration reactions, whereas the aluminate and ferrite phases do frequently persist in the anhydrous state. These relict phases may be distinguished through their peculiar chemical, mineralogical and textural features. These observations raise interesting questions concerning the long-term hydration kinetics of clinker phases and the durability behaviour of cementitious materials in operating conditions.

scholarly journals Microstructural constraints on magmatic mushes under Kīlauea Volcano, Hawaiʻi

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Penny E. Wieser ◽  
Marie Edmonds ◽  
John Maclennan ◽  
John Wheeler
Keyword(s):  
Spatial Distribution ◽  
Dendritic Growth ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Kilauea Volcano ◽  
Kīlauea Volcano ◽  
Mantle Peridotites ◽  
Wide Range ◽  
Electron Backscatter ◽  
Backscatter Diffraction

AbstractDistorted olivines of enigmatic origin are ubiquitous in erupted products from a wide range of volcanic systems (e.g., Hawaiʻi, Iceland, Andes). Investigation of these features at Kīlauea Volcano, Hawaiʻi, using an integrative crystallographic and chemical approach places quantitative constraints on mush pile thicknesses. Electron backscatter diffraction (EBSD) reveals that the microstructural features of distorted olivines, whose chemical composition is distinct from undistorted olivines, are remarkably similar to olivines within deformed mantle peridotites, but inconsistent with an origin from dendritic growth. This, alongside the spatial distribution of distorted grains and the absence of adcumulate textures, suggests that olivines were deformed within melt-rich mush piles accumulating within the summit reservoir. Quantitative analysis of subgrain geometry reveals that olivines experienced differential stresses of ∼3–12 MPa, consistent with their storage in mush piles with thicknesses of a few hundred metres. Overall, our microstructural analysis of erupted crystals provides novel insights into mush-rich magmatic systems.

scholarly journals The Effect of Simultaneous Si and Ti/Mo Alloying on High-Temperature Strength of Fe3Al-Based Iron Aluminides

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4268
Author(s):  
Věra Vodičková ◽  
Martin Švec ◽  
Pavel Hanus ◽  
Pavel Novák ◽  
Antonín Záděra ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Yield Stress ◽  
Electron Backscatter Diffraction ◽  
Xrd Analysis ◽  
Iron Aluminides ◽  
High Temperature Strength ◽  
X Ray Diffraction ◽  
Backscatter Diffraction

The effect of phase composition and morphology on high-temperature strength in the compression of Fe-Al-Si-based iron aluminides manufactured by casting was investigated. The structure and high-temperature strength in the compression of three alloys—Fe28Al5Si, Fe28Al5Si2Mo, and Fe28Al5Si2Ti—were studied. Long-term (at 800 °C for 100 h) annealing was performed for the achievement of structural stability. The phase composition and grain size of alloys were primarily described by means of scanning electron microscopy equipped with energy dispersive analysis and Electron Backscatter Diffraction (EBSD). The phase composition was verified by X-ray diffraction (XRD) analysis. The effect of Mo and Ti addition as well as the effect of long-term annealing on high-temperature yield stress in compression were investigated. Both additives—Mo and Ti—affected the yield stress values positively. Long-term annealing of Fe28Al5Si-X iron aluminide alloyed with Mo and Ti deteriorates yield stress values slightly due to grain coarsening.

scholarly journals Dislocation Creep of Olivine and Amphibole in Amphibole Peridotites from Åheim, Norway

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1018
Author(s):  
Sejin Jung ◽  
Takafumi Yamamoto ◽  
Jun-ichi Ando ◽  
Haemyeong Jung
Keyword(s):  
Electron Microscopy ◽  
Slip System ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Dislocation Creep ◽  
Transmission Electron ◽  
Electron Backscatter ◽  
Different Types ◽  
Localized Shear Deformation ◽  
Backscatter Diffraction

Amphibole peridotite samples from Åheim, Norway, were analyzed to understand the deformation mechanism and microstructural evolution of olivine and amphibole through the Scandian Orogeny and subsequent exhumation process. Three Åheim amphibole peridotite samples were selected for detailed microstructural analysis. The Åheim amphibole peridotites exhibit porphyroclastic texture, abundant subgrain boundaries in olivine, and the evidence of localized shear deformation in the tremolite-rich layer. Two different types of olivine lattice preferred orientations (LPOs) were observed: B- and A-type LPOs. Electron backscatter diffraction (EBSD) mapping and transmission electron microscopy (TEM) observations revealed that most subgrain boundaries in olivine consist of dislocations with a (001)[100] slip system. The subgrain boundaries in olivine may have resulted from the deformation of olivine with moderate water content. In addition, TEM observations using a thickness-fringe method showed that the free dislocations of olivine with the (010)[100] slip system were dominant in the peridotites. Our data suggest that the subgrain boundaries and free dislocations in olivine represent a product of later-stage deformation associated with the exhumation process. EBSD mapping of the tremolite-rich layer revealed intracrystalline plasticity in amphibole, which can be interpreted as the activation of the (100)[001] slip system.

The Occurrence of a Peripheral Coarse Grain Zone (PCGZ) in Extruded Bars of AA 7108

2021 ◽  
Vol 1016 ◽  
pp. 1141-1146
Author(s):  
Saul Hissaci de Souza ◽  
Ronald Lesley Plaut ◽  
Nelson Batista de Lima ◽  
Rene Ramos de Oliveira ◽  
Angelo Fernando Padilha
Keyword(s):  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Polarized Light ◽  
Coarse Grain ◽  
X Ray Diffraction ◽  
Rectangular Section ◽  
X Ray ◽  
Analysis Techniques ◽  
Coarse Grains ◽  
Backscatter Diffraction

Industrial-scale extruded profiles of AA 7108 with a rectangular section (25.60 mm x 15.95 mm) were used in this investigation. Some complementary microstructural analysis techniques, such as polarized light microscopy, EBSD (Electron Backscatter Diffraction) and X-ray diffraction were used to characterize the microstructure, focusing on the PCG zone. It was observed that the extruded profiles presented a totally recrystallized microstructure and a 300 μm layer of peripheral coarse grains. Additionally, the results showed that the PCGZ predominant grain orientation {311} <110> differs from the texture below the PCGZ (Goss and Cube components).

scholarly journals Evolution Of Precipitate Morphology During Extrusion In Mg ZK60A Alloy

2015 ◽  
Vol 60 (2) ◽  
pp. 1423-1426 ◽  
Author(s):  
J. Park ◽  
K.H. Jung ◽  
G.A. Lee ◽  
M. Kawasaki ◽  
B. Ahn
Keyword(s):  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Extrusion Process ◽  
Formation Mechanisms ◽  
Precipitate Morphology ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Evolution Of Precipitates

Abstract In this study, a continuously casted ZK60A magnesium alloy (Mg-Zn-Zr) was extruded in two different extrusion ratios, 6:1 and 10:1. The evolution of precipitates was investigated on the two extruded materials and compared with that of as-casted material. The microstructural analysis was performed by electron backscatter diffraction and transmission electron microscopy, and the compositional information was obtained using energy-dispersive X-ray spectroscopy. Several distinct morphologies of precipitates were observed, such as dot, rod, and disk shaped. The formation mechanisms of those precipitates were discussed with respect to the heat and strain during the extrusion process.

Microstructural Analysis of Biomedical Co-Cr-Mo Alloy Subjected to High-Pressure Torsion Processing

2014 ◽  
Vol 616 ◽  
pp. 263-269
Author(s):  
Murat Isik ◽  
Mitsuo Niinomi ◽  
Ken Cho ◽  
Masaaki Nakai ◽  
Junko Hieda ◽  
...  
Keyword(s):  
High Pressure ◽  
Vickers Hardness ◽  
High Strain ◽  
High Pressure Torsion ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Equivalent Strain ◽  
Ε Phase ◽  
Backscatter Diffraction ◽  
Equiaxed Grains

The effect of high-pressure torsion (HPT) processing on the microstructure and Vickers hardness of Co-Cr-Mo (CCM) alloys were investigated in this study. The microstructure of initial CCM alloy contains equiaxed grains with a grain diameter of approximately 50 μm and twins. The clear grain boundaries of equiaxed grains and twins disappear after HPT processing at a rotation number, N, of 10. The phase maps of initial CCM alloy and CCM alloy subjected to HPT processing at N = 5 measured by electron backscatter diffraction exhibit that the ratio of γ phase decreases from 93.5% to 34.1% and the ratio of ε phase increases from 6.5% to 65.9% by applying HPT processing. These results indicate that the ε phase is formed by high-strain, which is induced by the HPT processing. The Vickers hardness values on the surfaces of the CCM alloys subjected to HPT processing at N = 1, 5, and 10 increase with increasing the equivalent strain, εeq. These results suggest that an increase of Vickers hardness is correlated to an increase of the ratio of ε phase and the dislocation density, and grain refinement, which are caused by the high-strain induced by HPT processing.

scholarly journals Recent Advances in High-Speed Orientation Mapping

2006 ◽  
Vol 14 (6) ◽  
pp. 6-9 ◽  
Author(s):  
Matthew M. Nowell ◽  
Martina Chui-Sabourin ◽  
John O. Carpenter
Keyword(s):  
High Speed ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Automated Analysis ◽  
Steady Increase ◽  
Analysis Tool ◽  
Early Adopters ◽  
Orientation Mapping ◽  
Backscatter Diffraction ◽  
Acquisition Rates

Orientation mapping via automated analysis of Electron Backscatter Diffraction (EBSD) patterns has developed into an established microstructural analysis tool in the electron microscopy community. From the early 1990s, when this technique became commercially available, there has been a steady increase in the data acquisition rates as shown in Figure 1. Currently, orientation mapping speeds of over 200 analyzed patterns per second have been achieved. With these types of acquisition rates now available, the strategy on how to best use EBSD and orientation mapping has also shifted. Early adopters of this technique had to allocate hours of Scanning Electron Microscope (SEM) beam time in order to collect statistically significant data. With current technology, what was collected in hours can now be obtained in minutes. The goal of this article is to introduce this high-speed orientation mapping and present results illustrating the benefits of this capability.

Influence of Bonding Pressure on the Mechanical Properties of Copper Bumps

2012 ◽  
Author(s):  
S. M. L. Nai ◽  
H. J. Lu ◽  
C. K. Cheng ◽  
J. Wei
Keyword(s):  
Mechanical Properties ◽  
Electron Backscatter Diffraction ◽  
Bonding Temperature ◽  
Threshold Value ◽  
Bonding Pressure ◽  
Thermocompression Bonding ◽  
The Individual ◽  
Backscatter Diffraction

Thermocompression bonding is one of the key ways to form interconnections in many hetegrogeneous devices. The quality of metallic joints formed using thermocompression is predominantly determined by the bonding temperature and pressure. In order to achieve a strong and reliable joint, metallic joints in particular copper, which has an oxidative nature, require a high bonding temperature (> 300 °C). However, thermomechanical-related stresses induced during bonding can compromise the performance of the interconnections in the long term. Thus, one way to manage this is to lower the bonding temperature used in forming the interconnections. In this study, copper-copper bonding is successfully demonstrated at a bonding temperature of 80 °C. In order to better understand the effect of bonding pressure on the joint’s performance, the mechanical properties of the individual bulk copper bumps are evaluated using the nanoindentation system. Studies are conducted on the bulk copper bumps subjected to different bonding pressures. Their corresponding yield strength and hardness results are then determined. It is observed that as the applied bonding pressure increases, the mechanical properties of the bulk copper bump reach a certain threshold value and beyond which, properties start to degrade. The microstructure and grain sizes of the copper bumps are also analyzed using the electron backscatter diffraction.

scholarly journals Effects of Yttrium on Microstructure Stability and Tensile Properties of China Low Activation Martensitic Steel

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 446 ◽  
Author(s):  
Guoxing Qiu ◽  
Dongping Zhan ◽  
Changsheng Li ◽  
Min Qi ◽  
Yongkun Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Martensitic Steel ◽  
Electron Backscatter Diffraction ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Microstructural Stability ◽  
Microstructure Stability ◽  
Transmission Electron ◽  
Backscatter Diffraction

This study investigated the microstructural stability and mechanical properties exhibited by China low activation martensitic (CLAM) steels with different yttrium (Y) contents over 3000 h of aging at 550 °C. Scanning electron microscopy, electron backscatter diffraction analysis, and transmission electron microscopy were employed to investigate the microstructural evolution of the steels. Results indicated that grain boundary migration was slow and the Laves phase precipitation was delayed in Y-containing steels. Grain boundaries at different angles in 0Y and 6Y CLAM steels were significantly affected, and those in 36Y and 71Y alloys exhibited negligible changes during the long-term thermal aging. Moreover, Y contents had appreciable effects on the strength and toughness of the aged steels. The stable microstructure of Y-containing CLAM alloys is responsible for improved strength and impact toughness during aging.

Assessment of Welding-Induced Plasticity in Austenitic Steel Weldments

2016 ◽  
Author(s):  
Ondrej Muránsky ◽  
Cory J. Hamelin ◽  
Minh Tran ◽  
Chedly Braham ◽  
Michael C. Smith
Keyword(s):  
Structural Integrity ◽  
Electron Backscatter Diffraction ◽  
Constitutive Models ◽  
Region Of Interest ◽  
Characterization Methods ◽  
Macro Scale ◽  
Proper Definition ◽  
Aisi 316 ◽  
Definition Of ◽  
Backscatter Diffraction

Historically, weld residual stresses (WRS) have been used as the primary validation parameter for welding simulations, largely due to the importance of predicting WRS for structural integrity assessments. However, the extent of welding-induced plasticity (WIP) caused by the plastic flow of near-weld material is also an important characteristic affecting weld performance. WIP has been shown to negatively affect weld integrity, since the associated accumulation of defects (dislocations) in the material will accelerate the nucleation of macro-scale defects that lead to component failure. Information on WIP is particularly important when attempting to validate the constitutive models used for weld simulation, and can assist with the proper definition of material yield strength. The present study highlights two approaches to assess WIP in welded structures. The first approach involves the development of a micro-hardness correlation to infer the level of WIP across the near-weld region. The second approach uses electron backscatter diffraction (EBSD) data to directly calculate the average crystal misorientation in the region of interest, which is proportional to the amount of geometrically necessary dislocations present. The dissimilar approach to determine WIP between the two characterization methods allows a degree of confidence in the results obtained, therefore providing an accurate dataset for weld model validation. To exemplify this point, the two approaches are used to characterize WIP across a three-pass slot weld in AISI 316 steel (NeT TG4 specimen), and the results are compared to weld modelling predictions.

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