Crystallographic Textures Produced During Sand Blasting

2015 ◽  
Author(s):  
Saurabh Basu ◽  
Zhiyu Wang ◽  
Christopher Saldana
Keyword(s):  
Orientation Imaging Microscopy ◽  
Deformation Field ◽  
Flat Punch ◽  
Sand Blasting ◽  
First Order ◽  
In Situ Techniques ◽  
Orientation Imaging ◽  
Self Consistent

Evolution of crystallographic textures in sand blasted surfaces is studied. Sand blasting is approximated as a series of ideal cylindrical, flat punch and wedge indents. Features of the deformation field produced during indentation with these geometries is studied using in-situ techniques. Subsequently, crystallographic textures produced during indentation with these geometries is delineated using orientation imaging microscopy and simulated using the visco plastic self consistent framework. Finally, using a novel heuristic, the crystallographic textures created during indentation are related to those produced during sand blasting. It was seen that the heuristic is able perform a first order replication of empirically observed crystallographic textures.

scholarly journals Deformation field heterogeneity in punch indentation

2014 ◽  
Vol 470 (2166) ◽  
pp. 20130807 ◽  
Author(s):  
Tejas G. Murthy ◽  
Christopher Saldana ◽  
Matthew Hudspeth ◽  
Rachid M'Saoubi
Keyword(s):  
Crystallographic Texture ◽  
High Speed ◽  
Plastic Material ◽  
Deformation Field ◽  
Flat Punch ◽  
Hardening Material ◽  
Perfectly Plastic ◽  
Shear Type ◽  
Heterogeneous Deformation

Plastic heterogeneity in indentation is fundamental for understanding mechanics of hardness testing and impression-based deformation processing methods. The heterogeneous deformation underlying plane-strain indentation was investigated in plastic loading of copper by a flat punch. Deformation parameters were measured, in situ , by tracking the motion of asperities in high-speed optical imaging. These measurements were coupled with multi-scale analyses of strength, microstructure and crystallographic texture in the vicinity of the indentation. Self-consistency is demonstrated in description of the deformation field using the in situ mechanics-based measurements and post-mortem materials characterization. Salient features of the punch indentation process elucidated include, among others, the presence of a dead-metal zone underneath the indenter, regions of intense strain rate (e.g. slip lines) and extent of the plastic flow field. Perhaps more intriguing are the transitions between shear-type and compression-type deformation modes over the indentation region that were quantified by the high-resolution crystallographic texture measurements. The evolution of the field concomitant to the progress of indentation is discussed and primary differences between the mechanics of indentation for a rigid perfectly plastic material and a strain-hardening material are described.

A TEM Study of Dynamic Continuous Recrystallization in a Superplastic AL-4MG-0.3SC Alloy

1999 ◽  
Vol 601 ◽  
Author(s):  
L.M. Dougherty ◽  
I.M. Robertson ◽  
J.S. Vetrano
Keyword(s):  
True Strain ◽  
Orientation Imaging Microscopy ◽  
Superplastic Forming ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Continuous Recrystallization ◽  
Cold Rolled ◽  
Nominal Temperature

AbstractAn Al-4Mg-0.3Sc alloy, aged at 280°C for 8 hours and cold rolled to a 70% reduction, exhibited dynamic recrystallization during superplastic forming at 460°C and at a strain rate of 10−3sec−1. To understand the progression of recrystallization during forming, specimens were deformed under these same conditions to 0.1, 0.2, 0.4 and 0.8 true strain and studied postmortem using optical microscopy, transmission electron microscopy and orientation imaging microscopy. The microstructural evolution that occurred between each strain state was directly observed during deformation experiments at a nominal temperature of 460°C in the transmission electron microscope. These in-situ experiments showed the migration, coalescence, disintegration and annihilation of subboundaries. This combination of post-mortem analysis of specimens strained in bulk with real time observations made during these in-situ experiments allows the mechanisms operating during dynamic continuous recrystallization to be ascertained.

Impact of Local Texture on Recrystallization and Grain Growth via In Situ EBSD

2005 ◽  
Vol 495-497 ◽  
pp. 1121-1130 ◽  
Author(s):  
Stuart I. Wright ◽  
David P. Field ◽  
Matthew M. Nowell
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Electron Backscatter Diffraction ◽  
Three Dimensional ◽  
Orientation Imaging Microscopy ◽  
Boundary Mobility ◽  
Orientation Relationships ◽  
In Situ Techniques ◽  
Grain Boundary Mobility

While electron backscatter diffraction (EBSD) has become an established technique within materials characterization labs around the world, the technique is still relatively young and new applications are continuing to emerge. Automated EBSD or Orientation Imaging Microscopy (OIM) systems are being used in combination with other equipment within the scanning electron microscope (SEM) to perform in-situ measurements. This includes tensile stages for observing changes in local orientation during deformation and heating stages for studying orientation changes arising during recrystallization and grain growth as well as phase transformations. In addition to these temporally three-dimensional studies, spatially three-dimensional studies can be performed by in-situ serial sectioning in microscopes equipped with both electron and focused ion beams. These in-situ techniques are briefly reviewed. The review is followed by a detailed analysis of in-situ heating experiments on copper. The movement of grain boundaries during recrystallization and subsequent grain growth are tracked. The effect of orientation relationships on grain boundary mobility and nucleation are explored. No special relationship with grain boundary mobility was observed. However, twins appear to play a significant role in the nucleation process.

Study of diffusionless and diffusional transformations using in situ cooling and heating techniques in a scanning electron microscope

2020 ◽  
Vol 378 (2186) ◽  
pp. 20200284 ◽  
Author(s):  
Deepak Kumar ◽  
Rajdeep Sarkar ◽  
Vajinder Singh ◽  
Suraj Kumar ◽  
Chandan Mondal ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Materials Science ◽  
Pure Copper ◽  
Orientation Imaging Microscopy ◽  
Copper Oxides ◽  
Maximum Temperature ◽  
Orientation Imaging ◽  
Scanning Electron

In situ electron microscopy can be an effective tool to investigate the underlying science of many transformation mechanisms in materials science. Useful utilization of these experimentations will provide greater insight into many of the existing theories, as microstructural changes can be visualized in real time under some applied constraints. In this study, we have investigated two basic phase transformation phenomena: diffusionless and diffusional mechanisms with the help of in situ cooling and heating techniques in scanning electron microscope (SEM). In situ cooling experiments have been carried out on secondary hardening ultra-high-strength steels to understand the diffusionless transformation of austenite to martensite. Nucleation and growth of the martensites have been observed with cooling in different steps to −194°C. Details of the formation of different variants of martensites in steel were studied with the help of orientation imaging microscopy. Diffusional transformations were studied in terms of oxidation of pure copper in SEM using in situ heating technique. Different heating cycles were adopted for different samples by in situ heating to a maximum temperature of 950°C for the oxidation study. Nucleation of copper oxides and subsequent growth of the copper oxides at different temperatures were studied systematically. Raman spectroscopy and orientation imaging were done to confirm the formation of oxides and their orientations. The thermal cycling phenomenon was replicated inside SEM with heating and cooling and it has been demonstrated how the nature of copper and its oxides changes with the thermal cycle. This article is part of a discussion meeting issue ‘Dynamic in situ microscopy relating structure and function’.

Fabrication Technologies and Applications of Graphene-based co-polymeric Nano-composites: its challenges and Future works

2019 ◽  
Vol 09 ◽  
Author(s):  
Pratik Chhapia ◽  
Harshad Patel
Keyword(s):  
Review Paper ◽  
Polymeric Coating ◽  
Nano Composites ◽  
Future Prospects ◽  
Electrical And Optical Properties ◽  
In Situ Techniques ◽  
Surface Areas ◽  
Ink Jet ◽  
Enhanced Conductivity

: Graphene based co-polymeric Nano-composites explored and trending in various applications as ascribing to its enhanced conductivity and controlled modification with wide specific surface areas. With the number of advantages of co-polymeric coating on Graphene or Graphene sheets and their derivatives, Graphene based co-polymeric Nano-composites fabricated by various techniques (deposition, ink jet, electro spinning, spin coating, in-situ techniques, etc.) and different conducting co-polymers show its exceptional chemical, mechanical, electrical and optical properties. Therefore, in the today’s world with greater quantities of various properties of co-polymer with Graphene based Nano-composites with enhanced stability, selectivity and sensitivity have been formed. In this review paper, we have particularly focused on recent advancing in fabrication of different technologies with the help of Graphene based co-polymeric Nano-composites and its various trending and future applications. Finally, on the personal standpoint; the key challenges of Graphene based co-polymeric Nano-composites are mentioned in hope to shed a light on their potential future prospects.

scholarly journals Understanding Selectivity in CO2 Hydrogenation to Methanol for MoP Nanoparticle Catalysts Using In Situ Techniques

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 143
Author(s):  
Melis S. Duyar ◽  
Alessandro Gallo ◽  
Samuel K. Regli ◽  
Jonathan L. Snider ◽  
Joseph A. Singh ◽  
...  
Keyword(s):  
Formation Rate ◽  
Methanol Conversion ◽  
Transition Metal Catalysts ◽  
Colloidal Synthesis ◽  
X Ray ◽  
In Situ Techniques ◽  
Methanol Formation ◽  
Diffuse Reflectance Infrared ◽  
Formate Intermediate

Molybdenum phosphide (MoP) catalyzes the hydrogenation of CO, CO2, and their mixtures to methanol, and it is investigated as a high-activity catalyst that overcomes deactivation issues (e.g., formate poisoning) faced by conventional transition metal catalysts. MoP as a new catalyst for hydrogenating CO2 to methanol is particularly appealing for the use of CO2 as chemical feedstock. Herein, we use a colloidal synthesis technique that connects the presence of MoP to the formation of methanol from CO2, regardless of the support being used. By conducting a systematic support study, we see that zirconia (ZrO2) has the striking ability to shift the selectivity towards methanol by increasing the rate of methanol conversion by two orders of magnitude compared to other supports, at a CO2 conversion of 1.4% and methanol selectivity of 55.4%. In situ X-ray Absorption Spectroscopy (XAS) and in situ X-ray Diffraction (XRD) indicate that under reaction conditions the catalyst is pure MoP in a partially crystalline phase. Results from Diffuse Reflectance Infrared Fourier Transform Spectroscopy coupled with Temperature Programmed Surface Reaction (DRIFTS-TPSR) point towards a highly reactive monodentate formate intermediate stabilized by the strong interaction of MoP and ZrO2. This study definitively shows that the presence of a MoP phase leads to methanol formation from CO2, regardless of support and that the formate intermediate on MoP governs methanol formation rate.

scholarly journals Selected In Situ Hybridization Methods: Principles and Application

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3874
Author(s):  
Dominika Veselinyová ◽  
Jana Mašlanková ◽  
Katarina Kalinová ◽  
Helena Mičková ◽  
Mária Mareková ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Imaging Techniques ◽  
Cell Communication ◽  
Probe Design ◽  
Rapid Progress ◽  
In Situ Techniques ◽  
Different Types ◽  
Laboratory Procedures ◽  
The Individual

We are experiencing rapid progress in all types of imaging techniques used in the detection of various numbers and types of mutation. In situ hybridization (ISH) is the primary technique for the discovery of mutation agents, which are presented in a variety of cells. The ability of DNA to complementary bind is one of the main principles in every method used in ISH. From the first use of in situ techniques, scientists paid attention to the improvement of the probe design and detection, to enhance the fluorescent signal intensity and inhibition of cross-hybrid presence. This article discusses the individual types and modifications, and is focused on explaining the principles and limitations of ISH division on different types of probes. The article describes a design of probes for individual types of in situ hybridization (ISH), as well as the gradual combination of several laboratory procedures to achieve the highest possible sensitivity and to prevent undesirable events accompanying hybridization. The article also informs about applications of the methodology, in practice and in research, to detect cell to cell communication and principles of gene silencing, process of oncogenesis, and many other unknown processes taking place in organisms at the DNA/RNA level.

Influence of Dynamic Recrystallisation on Texture Formation in ECAP deformed Nickel

2007 ◽  
Vol 558-559 ◽  
pp. 575-580 ◽  
Author(s):  
Werner Skrotzki ◽  
Burghardt Klöden ◽  
I. Hünsche ◽  
Robert Chulist ◽  
Satyam Suwas ◽  
...  
Keyword(s):  
Orientation Imaging Microscopy ◽  
High Energy ◽  
Texture Gradient ◽  
Texture Formation ◽  
Microstructure Formation ◽  
Fcc Metals ◽  
Orientation Imaging ◽  
Angular Pressing ◽  
Dynamic Recrystallisation ◽  
Number Of Passes

3N nickel has been deformed by equal channel angular pressing (ECAP) at 400°C up to 3 passes using route A. The texture with respect to position in the deformed billet, i.e. from top to bottom, has been measured with high-energy synchrotron radiation. It is characterized by texture components typical for simple shear in the intersection plane of the square-shaped 90° bent channel. Besides, an oblique cube component is observed. Orientation imaging microscopy clearly shows that this component is due to partial recrystallization. Intensities of the texture components as well as deviations from their ideal shear positions vary from the top to the bottom of the billet and with the number of passes. The change of the intensity of texture components and the texture gradient investigated is discussed. Special emphasis is put on the influence of dynamic recrystallization on texture and microstructure formation during ECAP of fcc metals.

Ultra Grain Refinement of Low C Steels by Accumulative Roll Bonding

2006 ◽  
Vol 503-504 ◽  
pp. 311-316 ◽  
Author(s):  
I. Salvatori
Keyword(s):  
Accumulative Roll Bonding ◽  
Orientation Imaging Microscopy ◽  
Low Carbon Steel ◽  
Small Samples ◽  
Low Carbon ◽  
High Angle ◽  
Misorientation Distribution ◽  
Roll Bonding ◽  
Orientation Imaging ◽  
Annealing Conditions

Refinement of grain size is one of the biggest challenges to produce steels with improved combination of strength and toughness. Ultrafine structures are being produced world-wide on various materials, including low carbon steel, using different types of processes. However, the majority of these processes also exhibit severe limitations because they are generally restricted to small samples and are difficult to be implemented on an industrial scale. A promising technique for industrial implementation is the Accumulative Roll Bonding (ARB), a process able to supply large samples, even in the laboratory scale. In this paper, warm intense straining (ε = 4) by ARB was applied to a plain low-C steel in order to develop ultrafine grains, aiming at sizes around 1-2 μm, suitable to maintain an adequate combination of strength and ductility. The effect of annealing conditions on the evolution of the work-hardened microstructure and the bonding behaviour after each pass were investigated. Orientation Imaging Microscopy was used to investigate the microstructure and give a quantitative assessment of high angle and low angle boundaries. It is showed that the frequency of high angle grain boundaries increases with the strain but the misorientation distribution remained far from that typical of a recrystallised material.

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