scholarly journals ANALYSIS OF DEFORMATION PROCESSES OF MAGNESIUM ALLOY AT ELEVATED TEMPERATURES BY ORIENTATION MAPPING

2011 ◽  
Vol 23 (1) ◽  
pp. 53 ◽  
Author(s):  
Ping Yang ◽  
Li Meng ◽  
Yisong Hu ◽  
Zude Zhao ◽  
Xueping Ren
Keyword(s):  
Magnesium Alloy ◽  
Elevated Temperatures ◽  
Plastic Slip ◽  
Rotation Axes ◽  
Orientation Mapping ◽  
Back Scattering ◽  
Deformation Processes ◽  
Relationship Of ◽  
The Relationship

Orientation mapping based on electron back scattering diffraction technique was applied to reveal the distributions of disorientations and rotation axes of grains caused by plastic slip and twinning during channel die compression in magnesium alloy ZA31. In addition, the orientations of dynamically recrystallized grains and deformed grains were separated and compared with respect to their initial textures. The relationship of strain and {1012} twin amount was determined quantitatively by referring to twin orientations. The reasons leading to the observed phenomena are analyzed and discussed.

The Structure Property Relationship of Erosion Resistant Thermal Spray Coatings

1998 ◽  
Author(s):  
R.C. Tucker ◽  
A.A. Ashari
Keyword(s):  
Thermal Spray ◽  
Elevated Temperatures ◽  
Erosion Resistance ◽  
Industrial Applications ◽  
Thermal Spray Coatings ◽  
Steam Turbines ◽  
Structure Property ◽  
Spray Coatings ◽  
Relationship Of ◽  
The Relationship

Abstract Thermal spray coatings are widely used for erosion resistance, but the relationship between the microstructure of the coatings and their erosion resistance is not well understood. In this paper the performance of several commonly used coatings at ambient and elevated temperatures is reviewed in light of the coatings' structure and compared with a new coating. Two high temperature industrial applications, solid particle erosion in steam turbines and alumina-based erosion have been chosen to illustrate the significance of a coating's structure on its performance.

Permittivity Study of a CuCl Residue at 13–450 °C and Elucidation of the Microwave Intensification Mechanism for Its Dechlorination

2019 ◽  
Vol 38 (2019) ◽  
pp. 135-142
Author(s):  
Guo Zhanyong ◽  
Li Fachaung ◽  
Su Guang ◽  
Zhai Demei ◽  
Cheng Fang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Microwave Irradiation ◽  
Loss Factor ◽  
Elevated Temperatures ◽  
Temperature Dependent ◽  
Positive Interaction ◽  
Increasing Temperature ◽  
Relationship Of ◽  
The Relationship ◽  
Metallurgy Process

AbstractPermittivity is a vitally important parameter for describing the absorbing and heating characteristics of a material under microwave irradiation, and it is also strongly dependent on temperature. However, the literature contains little information on this topic and even less particular permittivity data at elevated temperatures. In this paper, the permittivity of a CuCl residue at temperatures from 13 to 450 °C at 2.45 GHz was measured using the cavity perturbation method. The relationship of its real part (ε′) and imaginary part (ε″) with temperature (T) was deduced. In addition, the temperature-dependent tangent (tan δ) and the penetration depth (d) of microwaves into the material were calculated. The results of the permittivity study show that the dielectric constant (ε′) of the CuCl residue increased linearly with increasing temperature. In contrast, the dielectric loss factor (ε″) and loss tangent first maintained on a steady value between 13 and 300 °C and then substantially increased from 300 to 450 °C. The positive interaction of the dielectric property and temperature showed the reasonableness of our earlier metallurgy process, where the CuCl residue for dechlorination was roasted at 350–450 °C under microwave irradiation.

Forming Limit Diagram of Magnesium Alloy ZK60 at Elevated Temperature

2011 ◽  
Vol 308-310 ◽  
pp. 2442-2445 ◽  
Author(s):  
Hong Wei Liu ◽  
Sheng Jie Yao ◽  
Wen Liang Liu ◽  
Zhao Duo Zhang
Keyword(s):  
Elevated Temperature ◽  
Magnesium Alloy ◽  
Grain Boundaries ◽  
Forming Limit Diagram ◽  
Strain Ratio ◽  
Instability Criterion ◽  
Forming Limit ◽  
Relationship Of ◽  
Zk60 Magnesium Alloy ◽  
The Relationship

The forming limit diagram of magnesium alloy ZK60 was developed with Hill’s instability criterion and M-K analysis. The relationship of forming limit with stain path, temperature and the thickness irregular coefficient were analyzed. The results show that the forming limit of ZK60 magnesium alloy increased little with the rising of strain ratio, but influenced greatly by the failure definition , and forming limit of is increased with the rising of temperature and thickness irregular coefficient, the most suitable value of f0 is 0.99, the fracture occur on the grain boundaries with significant cavities formation.

scholarly journals Models of transmission of COVID-19 with time under the influence of meteorological determinants

2020 ◽  
Author(s):  
Atin Adhikari ◽  
Shilpi Ghosh ◽  
Moon M. Sen ◽  
Rathin Adhikari
Keyword(s):  
Relative Humidity ◽  
Total Population ◽  
Elevated Temperatures ◽  
Structural Characteristics ◽  
Exponential Increase ◽  
Travel Restrictions ◽  
Before And After ◽  
The Usa ◽  
Relationship Of ◽  
The Relationship

AbstractBased on the statistical analyses of the data on the number of confirmed COVID-19 cases and meteorological determinants in some of the severely affected cities in Spain, Italy and the USA, some models are constructed showing the relationship of I′ (the number of infected individuals divided by the total population of a city) with temperature, relative humidity, wind velocity and time. Three models are based on the data before lockdown/travel restrictions in these cities, and the other three models are based on data both before and after lockdown/travel restrictions. These models, in general, indicate that the transmission of COVID-19 could be relatively high either for elevated temperatures with lower relative humidity or for lower temperatures with higher relative humidity conditions. Although one model indicates exponential increase in number of infection cases with time, the more statistically significant models show that the number of cases varies quadratically with time. We have discussed in short, how all these features could be linked with the alterations of structural characteristics of the SARS-CoV-2 virus. Finally, the possibility of natutal disappearance of COVID-19 pandemic, at the global level, has been discussed in the context of the most statistically significant model.

Microstructural Characteristics of Laser Metal Deposited Magnesium Alloy AZ31

2018 ◽  
Vol 941 ◽  
pp. 1004-1009
Author(s):  
Stefan Riekehr ◽  
Volker Ventzke ◽  
Anna Konovalovna ◽  
Nikolai Kashaev ◽  
Josephin Enz
Keyword(s):  
Additive Manufacturing ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Aluminium Alloys ◽  
Laser Additive Manufacturing ◽  
Microstructural Characteristics ◽  
Specific Strength ◽  
Structure Height ◽  
Relationship Of ◽  
The Relationship

Up to now, only a limited amount of metallic materials is investigated for laser additive manufacturing (LAM). However, the demand to widen the application possibilities by enlarging the range of materials for LAM is growing fast. By now, titanium and aluminium alloys are in the focus of research. In contrast, magnesium alloys are rarely used in the field of additive manufacturing, although they possess a low density in combination with a high specific strength. Currently, magnesium structures are mainly produced by casting but during the last years, the use of wrought alloys also increased. A reason for the rare use of magnesium alloys for LAM technologies might be the high flammability of magnesium powders. This difficulty can be avoided by using magnesium wire for laser metal deposition (LMD). In the present study, the microstructural characteristics of a LMD processed AZ31 magnesium alloy are investigated. For this purpose, optical microscopy and scanning electron microscopy were used. With the help of EDX and EBSD analysis, a change of the chemical composition and micro texture with structure height was identified. The relationship of microstructure and local mechanical properties was investigated with the help of Vickers micro hardness testing. Based on the obtained results it can be concluded that the microstructural characteristics of laser additive manufactured magnesium alloys differ from those of titanium and aluminium alloys. Thus, a wider application spectrum of LMD and magnesium alloys can be opened up.

An OIM Analysis on the Deformation Mechanism in Hot Compressed AZ31 Magnesium Alloy

2005 ◽  
Vol 488-489 ◽  
pp. 633-636 ◽  
Author(s):  
Li Meng ◽  
Ping Yang ◽  
Zude Zhao ◽  
Wei Min Mao
Keyword(s):  
Magnesium Alloy ◽  
Az31 Magnesium Alloy ◽  
Deformation Condition ◽  
Basal Texture ◽  
Slip Mechanism ◽  
Plastic Slip ◽  
Pyramidal Slip ◽  
Orientation Mapping ◽  
Ebsd Technique ◽  
Deformation Strain Rate

Orientation mapping based on EBSD technique was applied to analyze the rules of orientation evolution of grains in AZ31 magnesium alloy. Results show that not only under deformation strain rate of 1×10-2s-1, but under 4×10-4s-1(the superplastic deformation condition), grains in all samples with initial textures rotate gradually to near basal orientation ({0002} || compression plane) at different ways, and basal texture becomes stronger with increasing strain, which indicates plastic slip plays an important role during hot deformation. Otherwise, no evident non-basal pyramidal slip of <a+c> as some studies mentioned was observed in the sample with the initial basal texture, and the basal orientation is kept unchanged during the deformation process, which suggests that basal slip is the uppermost plastic slip mechanism in this sample. In addition, the phenomenon of viscous laminar flow was observed in the sample with initial basal texture.

Deformation Behaviour of an AX41 Magnesium Alloy at Elevated Temperatures

2007 ◽  
Vol 567-568 ◽  
pp. 321-324
Author(s):  
Zuzanka Trojanová ◽  
Pavel Lukáč ◽  
Zoltán Száraz
Keyword(s):  
Magnesium Alloy ◽  
Stress Relaxation ◽  
Strain Rate ◽  
Uniaxial Tension ◽  
Elevated Temperatures ◽  
Deformation Behaviour ◽  
Initial Strain Rate ◽  
Testing Temperature ◽  
Tension Tests ◽  
Deformation Processes

The deformation behaviour of the ternary magnesium alloy AX41 (4%Al-1%Ca-balance Mg) were investigated in uniaxial tension tests at temperatures between 20 and 300 °C and at an initial strain rate ranging in the order 10-4 s-1. The yield stress of the alloy is very sensitive to the testing temperature. Stress relaxation tests were performed with the aim to reveal physical base of deformation processes.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

Sign in / Sign up

Export Citation Format

Share Document