In Situ Observations of the Formation of Fine-Grained Mixed Microstructures of Acicular Ferrite and Bainite in the Simulated Coarse-Grained Heated-Affected Zone

2013 ◽  
Vol 85 (2) ◽  
pp. 243-250 ◽  
Author(s):  
Xiangliang Wan ◽  
Kaiming Wu ◽  
Gang Huang ◽  
Ran Wei
Keyword(s):  
Acicular Ferrite ◽  
Coarse Grained ◽  
Fine Grained ◽  
In Situ Observations

The critical influence of La content on the microstructure-toughness relationship in the simulated coarse-grained heat-affected zone of high-strength low-alloy steels

2021 ◽  
Vol 118 (2) ◽  
pp. 212
Author(s):  
Yuxin Cao ◽  
Xiangliang Wan ◽  
Feng Zhou ◽  
Hangyu Dong ◽  
Kaiming Wu ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Acicular Ferrite ◽  
High Strength ◽  
Coarse Grained ◽  
Low Alloy Steels ◽  
Fine Grained ◽  
Welding Thermal Cycle ◽  
Alloy Steels ◽  
High Fraction ◽  
The Impact

The present study was envisaged to investigate the role of La content on the particle, microstructure and toughness in the simulated coarse-grained heat-affected zone (CGHAZ) of high-strength low-alloy steels. Three steels with La content of 0.016 wt.%, 0.046 wt.% and 0.093 wt.% were prepared and simulated in a 100 kJ/cm heat input welding thermal cycle. Subsequently, the particle and microstructure of selected specimens were characterized and the impact absorb energy was measured at −20 °C. The results indicated that the La2O2S inclusions in 0.016 wt.%-La steel were gradually modified to LaS-LaP in 0.046 wt.%-La steel and to LaP in 0.093 wt.%-La steel. A higher fraction of acicular ferrite was obtained in the simulated CGHAZ of 0.016 wt.%-La steel, since the inclusion of La2O2S was more powerful to induce the formation of acicular ferrite. Furthermore, the fraction of M-A constituents in the simulated CGHAZ increased with increasing La content. The impact toughness in the simulated CGHAZ of 0.016 wt.%-La steel was the highest, owing to the high fraction of the fine-grained acicular ferrite and low fraction of M-A constituent.

Combined In Situ Neutron Diffraction and Acoustic Emission of Twin Nucleation & Twin Growth in Extruded ZM20 Mg Alloy

2010 ◽  
Vol 652 ◽  
pp. 149-154 ◽  
Author(s):  
Ondrej Muránsky ◽  
Matthew R. Barnett ◽  
David G. Carr ◽  
Sven C. Vogel ◽  
E.C. Oliver
Keyword(s):  
Acoustic Emission ◽  
Neutron Diffraction ◽  
Room Temperature ◽  
Coarse Grained ◽  
Fine Grained ◽  
Grain Sizes ◽  
Twin Nucleation ◽  
Twin Growth ◽  
In Situ Neutron Diffraction

In the present work in situ neutron diffraction and acoustic emission were used concurrently to study deformation twinning in two ZM20 Mg alloys with significantly different grain sizes at room temperature. The combination of these techniques allows differentionation between the twin nucleation and the twin growth mechanisms. It is shown, that yielding and immediate post-yielding plasticity in compression is governed primarily by twin nucleation, whereas the plasticity at higher strains is governed by twin growth. The current results further suggest that yielding by twinning happens in a slightly different manner in the fine-grained as compared to the coarse-grained alloy.

scholarly journals Ground-Penetrating Radar Evaluation of Moisture and Frost across Typical Saskatchewan Road Soils

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Curtis Berthelot ◽  
Diana Podborochynski ◽  
Timo Saarenketo ◽  
Brent Marjerison ◽  
Colin Prang
Keyword(s):  
Dielectric Constant ◽  
Moisture Content ◽  
Ground Penetrating Radar ◽  
Soil Type ◽  
Structural Condition ◽  
Coarse Grained ◽  
Fine Grained ◽  
Survey Results ◽  
Ground Penetrating

This study was undertaken to evaluate the effect of soil type, moisture content, and the presence of frost on road substructure permittivity. Permittivity sensitivity of typical road soils was characterized in the laboratory to provide baseline dielectric constant values which were compared to field ground penetrating radar (GPR) survey results. Both laboratory devices, the complex dielectric network analyzer and the Adek Percometer, as well as the field GPR system were used in this study to measure the dielectric constant of soils. All three systems differentiated between coarse-grained and fine grained soils. In addition, at temperatures below freezing, all three systems identified an increase in water content in soils; however, when frozen, the sensitivity of dielectric constant across soil type and moisture content was significantly reduced. Based on the findings of this study, GPR technology has the ability to characterize in situ substructure soil type and moisture content of typical Saskatchewan road substructure soils. Given the influence of road soil type and moisture content on in-service road performance, this ability could provide road engineers with accurate estimates of in situ structural condition of road structures for preservation and rehabilitation planning and optimization purposes.

In Situ Neutron Diffraction Study on the Mechanical Behavior of an Ultra-Fine-Grained Steel

2006 ◽  
Vol 524-525 ◽  
pp. 639-644 ◽  
Author(s):  
Kai Xiang Tao ◽  
Hahn Choo ◽  
H. Li ◽  
Bjørn Clausen ◽  
Donald W. Brown ◽  
...  
Keyword(s):  
Grain Size ◽  
Neutron Diffraction ◽  
High Strength ◽  
Neutron Diffraction Study ◽  
Coarse Grained ◽  
Transformation Induced Plasticity ◽  
Fine Grained ◽  
High Elongation ◽  
In Situ Neutron Diffraction

The martensitic phase transformation in an ultra fine grained (UFG) TRIP (transformation induced plasticity) steel with combination of high strength and high elongation was investigated during room temperature tensile test using in situ neutron diffraction. Two types of specimens, namely coarse grained (grain size of about 50 μm) and ultra-fine-grained (grain size of about 350 nm) specimens were examined. The lattice strain evolution of the austenite and martensite phases was observed and the load partitioning between the phases was identified.

scholarly journals Resolving multiple geological events using in situ Rb-Sr geochronology: implications for metallogenesis at Tropicana, Western Australia

2020 ◽  
Author(s):  
Hugo K. H. Olierook ◽  
Kai Rankenburg ◽  
Stanislav Ulrich ◽  
Christopher L. Kirkland ◽  
Noreen Evans ◽  
...  
Keyword(s):  
Western Australia ◽  
Coarse Grained ◽  
Thin Sections ◽  
Fine Grained ◽  
Regional Deformation ◽  
Mineral Assemblages ◽  
Two Generations ◽  
Minimum Age ◽  
First Time

Abstract. Dating multiple geological events in single samples using thermochronology and geochronology is relatively common but it is only with the recent advent of triple quadrupole LA-ICP-MS that in situ Rb-Sr dating has become a more commonly applied and powerful tool to date K- and Rb-bearing minerals. Here, we date, for the first time, two generations of mineral assemblages in individual thin sections using the in situ Rb-Sr method. Two distinct mineral assemblages, both probably associated with Au mineralization, are identified in samples from the Tropicana gold mine in the Albany–Fraser Orogen, Western Australia. For Rb-Sr purposes, the key dateable minerals are two generations of biotite, and additional phengite associated with the second assemblage. Our results reveal that the first, coarse-grained generation of biotite grains records a minimum age of 2535 ± 18 Ma, coeval with previous 40Ar/39Ar biotite, Re-Os pyrite and U-Pb rutile results. The second, fine-grained and recrystallized generation of biotite grains record an age of 1207 ± 12 Ma across all samples. Phengite and muscovite yielded broadly similar results at ca. 1.2 Ga but data is overdispersed for a single coeval population of phengite and shows elevated age uncertainties for muscovite. We propose that the ca. 2530 Ma age recorded by various geochronometers represents cooling and exhumation, and that the age of ca. 1210 Ma is related to major shearing associated with the regional deformation associated with Stage II of the Albany–Fraser Orogeny. This is the first time that an age of ca. 1210 Ma has been identified in the Tropicana Zone, which may have ramifications for constraining the timing of mineralization in the region. The in situ Rb-Sr technique is currently the only tool capable of resolving both geological events in these rocks.

scholarly journals Resolving multiple geological events using in situ Rb–Sr geochronology: implications for metallogenesis at Tropicana, Western Australia

Geochronology ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 283-303
Author(s):  
Hugo K. H. Olierook ◽  
Kai Rankenburg ◽  
Stanislav Ulrich ◽  
Christopher L. Kirkland ◽  
Noreen J. Evans ◽  
...  
Keyword(s):  
Western Australia ◽  
Inductively Coupled Plasma ◽  
Coarse Grained ◽  
Thin Sections ◽  
Inductively Coupled ◽  
Fine Grained ◽  
Mineral Assemblages ◽  
Two Generations ◽  
Minimum Age

Abstract. Dating multiple geological events in single samples using thermochronology and geochronology is relatively common, but it is only with the recent advent of triple quadrupole laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) that in situ rubidium–strontium (Rb–Sr) dating has become a more commonly applied and powerful tool to date K-rich or Rb-bearing minerals. Here, we date two generations of mineral assemblages in individual thin sections using the in situ Rb–Sr method. Two distinct mineral assemblages, both probably associated with Au mineralization, are identified in samples from the Tropicana gold mine in the Albany–Fraser Orogen, Western Australia. For Rb–Sr purposes, the key dateable minerals are two generations of biotite as well as additional phengite associated with the younger assemblage. Our results reveal that the first, coarse-grained generation of biotite grains records a minimum age of 2535±18 Ma, coeval with previous 40Ar∕39Ar biotite, rhenium–osmium (Re–Os) pyrite and uranium–lead (U–Pb) rutile results. The second, fine-grained and recrystallized generation of biotite grains record an age of 1207±12 Ma across all samples. Phengite and muscovite yielded broadly similar results at ca. 1.2 Ga, but data are overdispersed for a single coeval population of phengite and show elevated age uncertainties for muscovite. We propose that the ca. 2530 Ma age recorded by various geochronometers represents cooling and exhumation and that the age of ca. 1210 Ma is related to major shearing associated with the regional deformation as part of Stage II of the Albany–Fraser Orogeny. This is the first time that an age of ca. 1210 Ma has been identified in the Tropicana Zone, which may have ramifications for constraining the timing of mineralization in the region. The in situ Rb–Sr technique is currently the only tool capable of resolving both geological events in these rocks.

Geotechnical Properties of Nearshore Sediments of Canso Strait, Nova Scotia

1975 ◽  
Vol 12 (1) ◽  
pp. 44-57 ◽  
Author(s):  
J. D. Brown ◽  
M. A. Rashid
Keyword(s):  
Nova Scotia ◽  
Geotechnical Properties ◽  
Coarse Grained ◽  
Gravity Corer ◽  
Near Surface ◽  
Fine Grained ◽  
Lehigh University ◽  
Overconsolidated Clays ◽  
Nearshore Sediments

The results are reported of a field and laboratory investigation of the geotechnical properties of the surficial bottom, or near-surface, sediments of the Strait of Canso, Nova Scotia. The investigation procedures included in situ shear vane tests performed using a diver-operated apparatus lowered to the bottom from the survey ship, and undisturbed sampling using the Lehigh University Gravity Corer, which provides a 10 cm diameter sample.Soils encountered within the sampling depth (0–1.5 m maximum) consisted of layered and bioturbated coarse-grained and fine-grained sediments. Most of the investigative work was concerned with the fine-grained sediments, clayey silts, and clays, which were found to be soft and compressible, but possessed a reserve resistance in both shear and one-dimensional consolidation which give them the characteristics of overconsolidated clays. This reserve resistance has been attributed to chemical alteration, including the effects of organic compounds.

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