Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where A. Eliezer is active.

Publication


Featured researches published by A. Eliezer.


Corrosion Science | 2002

Corrosion behaviour of stressed magnesium alloys

P.L. Bonora; M. Andrei; A. Eliezer; E.M. Gutman

Abstract Potentiodynamic polarisation and impedance measurements are used to examine the corrosion aspects of some Mg-based alloys, which were previously stressed in order to established the effect of mechanical deformation on surface electrochemical reactions. A first approach was made for the unstressed alloys. The electrochemical tests were carried out in a sodium borate buffer solution.


Journal of Light Metals | 2001

Corrosion fatigue of die-cast and extruded magnesium alloys

A. Eliezer; E.M. Gutman; E. Abramov; Ya. Unigovski

Abstract To study the fatigue life of die-cast and extruded AZ91D, AM50 and AZ31 magnesium alloys, corrosion fatigue tests were carried out using a rotating beam type fatigue machine. Corrosive environment (3.5% NaCl) significantly decreases fatigue life of alloys, especially for extruded alloys. The fatigue data at high stresses were analyzed using fitting equations. Extruded alloys show a higher sensitivity to the action of NaCl solution in comparison with die-cast alloys; however, their corrosion fatigue life is longer than that of die-cast alloys. Corrosion fatigue behavior of Mg alloys correlates with their mechanochemical behavior. The latter was studied by the polarization measurements of the dissolution rate of strained alloys. TEM observations confirmed that the maximums on the curves of Mg dissolution rate dependence on the strain in NaCl solution appeared at the work-hardening stages due to the creation and destruction of dislocation pile-ups.


Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 2003

Corrosion fatigue of extruded magnesium alloys

Ya. Unigovski; A. Eliezer; E. Abramov; Y. Snir; E.M. Gutman

Abstract Corrosion fatigue tests were carried out on extruded AZ31 (3% Al, 1% Zn, 0.3% Mn, Mg—the rest), AM50 (5% Al, 0.4% Mn, Mg—the rest) and ZK60 (5% Zn, 0.5% Zr, Mg—the rest) Mg alloys in air, NaCl-based and borate solutions. N sol / N air ratios (the relative fatigue life) were used for the analysis of the corrosion fatigue behavior of Mg alloys in various environments, where N sol and N air are the numbers of cycles to failure in the solution and in air, respectively. Extruded ZK60 alloy reveals very high fatigue and corrosion fatigue properties in comparison with other alloys. However, it has the lowest relative fatigue life ( N sol / N air ∼10 −3 –10 −2 ) or the highest sensitivity to the action of NaCl-based solutions in comparison with that of AM50 and AZ31 alloys ( N sol / N air ∼10 −2 –10 −1 ). Under the same stress, the corrosion fatigue life of extruded alloys is significantly longer than that of die-cast alloys ( N sol for extruded AM50 in NaCl is two to three times longer than that of die-cast AM50).


Journal of Light Metals | 2002

Development of semisolid casting for AZ91 and AM50 magnesium alloys

Z. Koren; H Rosenson; E.M. Gutman; Ya. Unigovski; A. Eliezer

The feasibility of semisolid casting process with AZ91 and AM50 magnesium alloys, which are usually used for hot- and coldchamber die-casting, was investigated in this work. Two casting methods were examined: direct casting from the melting–stirring unit and billets casting. The billets had been precast with thixotropic properties, and were heated again by an induction furnace before the casting. The apparent viscosity of the semisolid magnesium slurry during continuous cooling was found as a function of the casting temperature. Viscosity tests show that the appropriate casting temperatures in the two-phase region were in the range of 595–575 C for AZ91 alloy and 620–614 C for AM50 alloy. At casting temperature of 585 C, AZ91 exhibited maximum density and the highest standard mechanical properties. AM50 alloy demonstrated the relative poor mechanical properties in the two-phase region. The toleration of heat treatment of semisolid AZ91 alloy with a 1.8-fold increase in the elongation-to-fracture was observed. No significant differences of the densities and the standard mechanical properties of the alloys between direct or billet castings were demonstrated. 2002 Elsevier Science Ltd. All rights reserved.


Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 2001

Mechanoelectrochemical behavior and creep corrosion of magnesium alloys

E.M. Gutman; A. Eliezer; Ya. Unigovski; E. Abramov

Abstract Both creep and corrosion resistances are significant problems in the application of magnesium alloys. The synergistic effect of corrosion and stress on the viscoelasticity of magnesium alloys named corrosion creep has been studied in die-cast AZ91D (Mg–9%Al–1%Zn) and AM50 (Mg–5% Al–0.4% Mn) alloys in air and in the borate buffer solution. The highest sensitivity to creep in the corrosive environment is observed in the alloy with the highest Al content. An electrochemical study under a tensile strain demonstrates a good correlation with corrosion creep tests.


Materials and Corrosion-werkstoffe Und Korrosion | 2002

DC and AC polarisation study on magnesium alloys Influence of the mechanical deformation

M. Andrei; A. Eliezer; P.L. Bonora; E.M. Gutman

Potentiodynamic polarisation and impedance measurements are used to examine the corrosion behaviour of some magnesium alloys, which were previously stressed in order to establish the effects of mechanical deformation on the electrochemical reactions at the interface alloy/electrolyte. Due to the increasing demand for joint parts of magnesium alloys there is a need to perform localised machining. For this reason it is interesting to study both the surface and the cross-section. DC und AC Polarisationsuntersuchung an Magnesiumlegierungen Einflus der mechanischen Verformung Potentiodynamische Polarisations- und Impedanzmessungen werden eingesetzt, um das Korrosionsverhalten verschiedener Magnesiumlegierungen zu untersuchen, die vorher mechanisch beansprucht wurden, um die Einflusse mechanischer Verformung auf die elektrochemischen Reaktionen an der Grenzflache Legierung/Elektrolyt zu erzeugen. Auf Grund der steigenden Nachfrage nach Verbindungsteilen aus Magnesiumlegierungen ist eine lokale mechanische Bearbeitung notwendig. Daher ist es von Interesse, sowohl die Oberflache als auch den Querschnitt zu untersuchen.


Journal of Materials Synthesis and Processing | 2000

Mechanoelectrochemical Behavior of Pure Magnesium and Magnesium Alloys Stressed in Aqueous Solutions

E.M. Gutman; Ya. Unigovski; A. Eliezer; E. Abramov

A new synergistic effect of corrosion and stress on the viscoelasticity of pure magnesium and magnesium alloys has been shown. This phenomenon named corrosion creep has been studied in 99.9653% Mg, die-cast AZ91D (Mg–9% Al–1% Zn), AM50 (Mg–5% Al–0.4% Mn), and AS21 (Mg–2.3% Al, 0.23% Mn, 1.10% Si) alloys. Creep tests were carried out at 25°C in air and in the borate buffer aqueous solution (pH 9.3). It is found that the highest sensitivity to creep in the corrosive environment is observed in the alloy with the highest Al content. This agrees with the data obtained earlier in the study of mechanoelectrochemical behavior and corrosion fatigue of Mg alloys. However, in air, the creep behavior of all alloys at room temperature is approximately the same. Creep life of pure magnesium and its alloys significantly decreases in a corrosive environment. Corrosion-creep cracks filled with magnesium hydroxide particles were observed by SEM–EDS analysis at the surface of AS21 alloy. The thickness of the oxide layer defined by AES in samples of AZ91D, AM50, and AS21 alloys placed for 2 h into the borate solution amounts to ∼540, ∼1320, and ∼1440 nm, respectively. This can be explained with the account for surface phenomena.


Materials Science Forum | 1998

Mechanoelectrochemical Behavior and Plasticity of Magnesium Alloys

A. Eliezer; E.M. Gutman; Hiroyo Haga; E. Aghion

The mechanical properties and mechanoelectrochemical effect (the effect of mechanical deformation on the surface electrochemical reactions) were investigated for some Mg-based alloys supposing that aluminum alloying influences them. A simple method of testing mechanoelectrochemical behavior of metals was developed. Potentiostatic polarization measurements on stressed electrode were carried out in chloride electrolyte. The correlation between the mechanoelectrochemical behavior and strain hardening stages is observed during plastic deformation. Maximum mechanoelectrochemical effect is achieved under intense strain hardening in the initial portion of this stage. The experimental observations are explained theoretically.


Journal of Materials Science Letters | 2001

Corrosion creep of magnesium-based alloys

E.M. Gutman; Ya. Unigovski; A. Eliezer; E. Abramov

In recent years special attention has been concentrated on Mg alloys as the lightest structural metal. However, their insufficient corrosion resistance and creep resistance limit Mg alloys application in automotive and aerospace industry. Until now these problems have been treated in many works separately as corrosion behavior in non-stressed state and creep in noncorrosive conditions. However, under real operational and environmental conditions mechanical and corrosion processes occur simultaneously, accelerating each other. This inevitably leads to the appearance of new synergistic effects that significantly reduce the lifetime of metals. For example, the failure of AZ91D alloy (Mg-9%Al-1%) exposed to a rural atmosphere while loaded in constant tension of 102 MPa (near 60% of yield strength) occurred within 10–100 days [1]. In the present work the effect of corrosive medium on the creep of some die-cast Mg alloys has been studied for the first time, and a phenomenon named “corrosion creep” has been found. Specimens (5.9 mm in diameter, gauge length of 75 mm) of Mg alloys AZ91D (Mg-8.4% Al, 0.85% Zn, 0.17% Mn), AM50 (Mg-5.1% Al, 0.15% Zn, 0.57% Mn) and AS21 (Mg-2.3% Al, 0.23% Mn, 1.10% Si)) were produced on a die-cast machine with the locking force of 2000 KN. To study the surface layer effect on corrosion creep, a surface layer 0.5 mm thick was removed by mechanical treatment from the surface of some specimens. Creep tension tests were carried out on Model 3 Satec machine at 25 ± 2 ◦C in air and in 0.1N Na2B4O7 buffer solution (pH 9.3) at stress values of 0.85 and 0.89 of tensile yield strength (TYS) for each alloy (Table I). Creep specimen 1 in a glass electrochemical cell 3 was placed into an averaging high-temperature


Journal of Materials Engineering and Performance | 2000

Effect of die-casting conditions on viscoelastic behavior of Mg alloy

E.M. Gutman; Ya. Unigovski; A. Eliezer; E. Aghion; Z. Koren

Creep and stress relaxation resistance of the most common die-cast Mg alloy AZ91D (Mg-9% Al-1% Zn) are influenced by both casting temperature and injection rate as well as by die temperature and porosity. Relationships between viscoelastic properties of Mg alloy at 150 °C and the parameters of die-casting technology are obtained and presented as simple contour plots (isograms). These properties can be improved by reducing casting temperature and increasing injection rate. When fabricating complicated thin-wall components, castability of the alloy can be diminished due to a fast temperature drop. In this case, casting temperature should be higher, whereas injection rate can be reduced. Porosity seems to be the most important characteristic of die-cast alloy microstructure affecting its viscoelastic properties. Coarse β-phase precipitates do not affect creep and relaxation characteristics of die-cast AZ91D alloy.

Collaboration


Dive into the A. Eliezer's collaboration.

Top Co-Authors

Avatar

E.M. Gutman

Ben-Gurion University of the Negev

View shared research outputs
Top Co-Authors

Avatar

Ya. Unigovski

Ben-Gurion University of the Negev

View shared research outputs
Top Co-Authors

Avatar

E. Abramov

Ben-Gurion University of the Negev

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

E. Aghion

Ben-Gurion University of the Negev

View shared research outputs
Top Co-Authors

Avatar

G. Ben-Hamu

Ben-Gurion University of the Negev

View shared research outputs
Top Co-Authors

Avatar

Z. Koren

Technion – Israel Institute of Technology

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

H Rosenson

Technion – Israel Institute of Technology

View shared research outputs
Top Co-Authors

Avatar

L. Riber

Ben-Gurion University of the Negev

View shared research outputs
Researchain Logo
Decentralizing Knowledge