scholarly journals Effects of initial microstructure on the earring of aluminium alloys cartridge case

10.30544/409 ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 11-22
Author(s):  
Ljubica M. Radovic ◽  
Jelena Marinkovic ◽  
Milorad Stanic
Keyword(s):  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Particle Distribution ◽  
Phase Particle ◽  
The Other ◽  
Second Phase ◽  
Local Difference ◽  
Cartridge Case ◽  
The One ◽  
Cartridge Cases

Defects obtained during impact extrusion of EN AW-5754 aluminium alloy during cartridge case production were investigated. In cartridge cases produced from the one metallurgical heat pronounced tendency to earing after impact extrusion observed/appeared. On the other hand the earing in cartridge cases from the other heat was not observed. Presence of earing is due to local difference in materials flow during extrusion. This behaviour is atriduted to dfference in second phase particle distribution in used preforms (slugs).

scholarly journals Contrasting effects of the onset of spring on reproductive success of Arctic-nesting geese

The Auk ◽  
2019 ◽  
Vol 137 (1) ◽  
Author(s):  
Bart A Nolet ◽  
Kees H T Schreven ◽  
Michiel P Boom ◽  
Thomas K Lameris
Keyword(s):  
Population Dynamics ◽  
Late Onset ◽  
The Other ◽  
Second Phase ◽  
Combined Effects ◽  
Negative Effects ◽  
Early Snowmelt ◽  
The One ◽  
Winter Flocks ◽  
Breeding Propensity

Abstract Breeding output of geese, measured as the proportion of juveniles in autumn or winter flocks, is lower in years with a late onset of spring in some species, but higher in at least one other species. Here we argue that this is because the timing of spring affects different stages of the reproductive cycle differently in different species. Because the effects on 2 different stages are opposite, the combined effects can result in either a positive or a negative overall effect. These stages are the pre-laying, laying, and nesting phase on the one hand; and the hatchling, fledgling, and juvenile phase on the other hand. The first phase is predominantly positively affected by an early snowmelt, with higher breeding propensity, clutch size, and nest success. The second phase in contrast is negatively affected by early snowmelt because of a mismatch with a nutrient food peak, leading to slow gosling growth and reduced survival. We argue that recognition of this chain of events is crucial when one wants to predict goose productivity and eventually goose population dynamics. In a rapidly warming Arctic, the negative effects of a mismatch might become increasingly important.

Orientation Mapping Study on the Inhomogeneous Microstructure Evolution during Annealing of 6013 Aluminum Alloy

2010 ◽  
Vol 163 ◽  
pp. 13-18 ◽  
Author(s):  
M. Bieda-Niemiec ◽  
Krzystof Sztwiertnia ◽  
A. Korneva ◽  
Tomasz Czeppe ◽  
R. Orlicki
Keyword(s):  
Aluminum Alloy ◽  
Particle Distribution ◽  
Phase Particle ◽  
Second Phase ◽  
Transmission Electron ◽  
Orientation Mapping ◽  
Initial Stage ◽  
Second Phase Particles ◽  
Cold Rolled

Orientation mapping in transmission electron microscope was successfully applied to study microstructural changes at the initial stage of recrystallization in the aluminum alloy with a bimodal second-phase particle distribution. The alloy samples were reversibly cold rolled resulting in the formation of laminar structure with zones of localized strain around large second-phase particles. Orientation mapping and in-situ investigations carry information about the processes which are active in the deformation zones during annealing.

HOW CAN WE STOP THE SEWAGE?

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
J. M. Sáez ◽  
M. J. M. Davis ◽  
M. L. Gutiérrez ◽  
A. Vallejo ◽  
L. Ayala
Keyword(s):  
Urban Areas ◽  
Social Acceptance ◽  
Optimal Solution ◽  
End Users ◽  
The Other ◽  
Design Parameters ◽  
Second Phase ◽  
Sociological Research ◽  
Black Water ◽  
The One

In Ecuador 46.4% of households lack access to sewerage systems, and then much wastewater is discharged from sewerage into the environment untreated. On the one hand dry toilet systems present themselves as an optimal solution against this backdrop; they mitigate the production of black water, whilst having fertilizer as the end product. On the other hand, they tend to have a low acceptance level by potential end users. This problem of social acceptance is then further exacerbated in urban areas. In order to overcome this, the design of an ecological dry/semi-dry toilet was carried out in two phases. The first phase consisted of purely sociological research, where the aim was to determine the basic design parameters that should be used for ecological toilet prototype. The second phase is the development of ecological toilet prototypes, which are then tested in terms of their level of acceptance/rejection by potential end users. The overall aim is to develop toilet prototypes that on the one hand mitigate the production of black water, whilst on the other are accepted with open arms by end users, and even preferred over the conventional toilet common to urban areas.

scholarly journals The Influence of Texture on the Ductile-to-Brittle Transition Behavior in Fe20Cr4.5Al Oxide Dispersion Strengthened Alloy

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 87
Author(s):  
Jesus Chao ◽  
Carlos Capdevila
Keyword(s):  
Yield Strength ◽  
Cleavage Plane ◽  
Phase Particle ◽  
Oxide Dispersion Strengthened ◽  
Dislocation Cell ◽  
The Other ◽  
Second Phase ◽  
Oxide Dispersion ◽  
Brittle Transition ◽  
Ductile To Brittle Transition

This paper reports on hardness, tensile properties and notch impact bending toughness values of an Fe20Cr4.5Al oxide dispersion strengthened (ODS) alloy specifically processed to achieved different preferential orientations: random, <100>, <110> and <111> parallel to the bar axis. In spite of the differences in the grain size, it was found for <100>, <111> and random orientations that the mean hardness values on the transverse cross sections is not remarkably sensitive to the texture. On the other hand, a significantly different mean hardness value for the material having the <110> crystalline orientation was found. Regarding the yield strength, it was found for random, <100> and <111> orientations that the yield strength is proportional to the Taylor’s factor. The difference between experimental and predicted yield strength values for <110> orientation was attributed to the offset effect induced by the dislocation cell size. The variation of the cleavage fracture strength with the texture was analyzed in the basis of two criteria: one based on the Normal Stress Law (macroscopic nature), and the other based on the assumption that fracture occurs from the propagation of a microcrack-like defect (microscopic nature). In this sense, it was concluded from the fractographic evidences that random and <100> orientations follow a mechanism where the fracture kinks along of the cleavage plane from a penny shaped microcrack nucleated in a second phase particle, meanwhile in the <110> and <111> orientations the fracture propagation arises from a penny shaped defect on the cleavage plane. Finally, the lower shelf values determined for the conditions studied are the same regardless of the texture and microstructure. The effect of texture on the notch toughness was noted where plastic flow predominates, i.e., in the ductile to brittle transition temperature and in the upper shelf energy.

scholarly journals Essai sur l’étude de la coopération bilatérale entre le Canada et l’Afrique francophone 1961-1981

2005 ◽  
Vol 13 (2) ◽  
pp. 263-281 ◽  
Author(s):  
Michel Houndjahoué
Keyword(s):  
Foreign Policy ◽  
The Other ◽  
Second Phase ◽  
Remarkable Increase ◽  
The Third ◽  
Third Phase ◽  
French Speaking ◽  
Bilateral Cooperation ◽  
The One ◽  
Le Canada

We have divided the evolution of bilateral cooperation between Canada and the French-speaking countries of Africa into three major phases. During the first phase, which lasted from 1961 to 1968, Canadian aid was slight and discontinuous. The second phase, from 1969 to 1975, was characterized by a remarkable increase of the CIDA 's activities. That period was specially influenced, on the one had, by the rudeau and Chevrier missions and, on the other hand, by the reconsideration of Canada's foreign policy during the 1970's. The third phase, from 1975 to 1981, was arked, among other things, by what one could call industrial cooperation, that is cooperation between « project-countries » and « program-countries ». We have tried to analyse the main characteristics of each of those three phases, while striving to « link » them to the socio-economic and political context of Canada and the French-speaking countries of Africa.

Effects of Deformation Temperature on Dynamic Recrystallization of 7A04-T6 Alloy

2011 ◽  
Vol 121-126 ◽  
pp. 121-125 ◽  
Author(s):  
Jian Min Yu ◽  
Zhi Min Zhang ◽  
Qiang Wang ◽  
Bao Hong Zhang
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Dynamic Recrystallization ◽  
Aluminium Alloy ◽  
Deformation Temperature ◽  
Phase Particle ◽  
High Strength ◽  
Fracture Morphology ◽  
Second Phase ◽  
Particle Nucleation

The influences of deformation temperature on microstructure dynamic recrystallization of 7A04-T6 ultra-high strength aluminium alloy by isothermal compression experiments in different deformation temperature on the 6300KN extrusion press. The experimental results show that both tensile strength and elongation increased with deformation temperature increasing. At 480°C, tensile strength reached 582Mpa and elongation increase to 9%. In the experiment, dynamic recrystallization of 7A04 aluminium alloy is mainly grain boundary nucleation and second phase particle nucleation. The grain size of 7A04-T6 aluminium alloy gradually refined with the deformation temperature increasing. Fracture morphology showed that rupture is belong to mixed rupture of intergranular and transgranular. With the deformation temperature increase to 480°C, grain size become small, the dimple in the fracture increase gradually, and existing the second phase particle in the dimple.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

CBED study of low-temperature InP grown by gas source MBE

1993 ◽  
Vol 51 ◽  
pp. 810-811
Author(s):  
R. Rajesh ◽  
M.J. Kim ◽  
J.S. Bow ◽  
R.W. Carpenter ◽  
G.N. Maracas
Keyword(s):  
Low Temperature ◽  
Second Phase ◽  
Material System ◽  
Ion Milling ◽  
Electrical Measurements ◽  
Gas Source ◽  
Structural And Electrical Properties ◽  
The One ◽  
Lt Inp ◽  
Gas Source Mbe

In our previous work on MBE grown low temperature (LT) InP, attempts had been made to understand the relationships between the structural and electrical properties of this material system. Electrical measurements had established an enhancement of the resistivity of the phosphorus-rich LT InP layers with annealing under a P2 flux, which was directly correlated with the presence of second-phase particles. Further investigations, however, have revealed the presence of two fundamentally different types of precipitates. The first type are the surface particles, essentially an artefact of argon ion milling and containing mostly pure indium. The second type and the one more important to the study are the dense precipitates in the bulk of the annealed layers. These are phosphorus-rich and are believed to contribute to the improvement in the resistivity of the material.The observation of metallic indium islands solely in the annealed LT layers warranted further study in order to better understand the exact reasons for their formation.

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