scholarly journals Microstructure, Mechanical, Corrosion, and Ignition Properties of WE43 Alloy Prepared by Different Processes

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 728
Author(s):  
Drahomír Dvorský ◽  
Jiří Kubásek ◽  
Klára Hosová ◽  
Miroslav Čavojský ◽  
Dalibor Vojtěch
Keyword(s):  
Solid Solutions ◽  
Ignition Temperature ◽  
Processing Technique ◽  
Intermetallic Phases ◽  
Alloying Elements ◽  
Minor Effect ◽  
Corrosion Properties ◽  
Mechanical And Corrosion Properties ◽  
A Minor ◽  
We43 Alloy

This paper deals with the effect of microstructure condition on ignition temperature, mechanical and corrosion properties of commercial WE43 alloy prepared by various processing techniques including conventional casting, extrusion, and powder metallurgy methods such as spark plasma sintering. For different processing technique, differences in microstructures were observed, including different grain sizes, intermetallic phases, amount of alloying elements in the solid solutions, or specific structural elements. Mechanical and corrosion properties were improved especially by grain refinement. Precipitation from oversaturated solid solutions led to further improvement of mechanical properties, while corrosion resistance was just slightly decreased due to the fine and homogeneously distributed precipitates of Mg41Nd5. The obtained results indicate huge differences in ignition resistance based on the metallurgical state of the microstructure. An improved ignition resistance was obtained at the condition with a higher concentration of proper alloying elements (Y, Nd, Gd, Dy) in the solid solution and absence of eutectic phases in the microstructure. Thermally stable intermetallic phases had a minor effect on resulting ignition temperature.

AZ31 and WE43 Alloys for Biomedical Applications

2017 ◽  
Vol 270 ◽  
pp. 205-211 ◽  
Author(s):  
Drahomír Dvorský ◽  
Jiří Kubásek ◽  
Dalibor Vojtěch
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloys ◽  
Biomedical Applications ◽  
Intermetallic Phases ◽  
Alloying Elements ◽  
Biodegradable Implants ◽  
Preparation Process ◽  
Magnesium Matrix ◽  
Corrosion Properties ◽  
Mechanical And Corrosion Properties

Magnesium and its alloys are considered for application as materials for biodegradable implants as they have mechanical properties similar to bone tissue. High demands on corrosion and mechanical properties are made on these alloys. While mechanical properties of magnesium are usually enhanced by alloying, corrosion properties may deteriorate. This paper is focused on the comparison of magnesium alloys AZ31 (3 wt. % Al, 1 wt. % Zn) and WE43 (4 wt. % Y, 3 wt. % Nd) which are considered for biomedical applications. Besides the type of alloying elements, the preparation process has also great impact on final mechanical and corrosion properties. Alloying elements may be dissolved in magnesium matrix or they can form intermetallic phases, which alter final properties. Microstructure, mechanical and corrosion properties of AZ31 and WE43 were studied and compared with pure magnesium.

ab-initio modelling of Mg:H interstitial solid solutions

2003 ◽  
Vol 801 ◽  
Author(s):  
M. Messina ◽  
F. Cleri ◽  
M. Volpe
Keyword(s):  
Ab Initio ◽  
Solid Solutions ◽  
Minor Effect ◽  
Heat Of Solution ◽  
Volume Deformation ◽  
Subsequent Formation ◽  
Exchange Correlation ◽  
The Difference ◽  
A Minor ◽  
Structure Calculations

ABSTRACTWe studied the thermodynamics of interstitial Mg:H solid solutions by means of ab-initio electronic structure calculations. Soft pseudopotentials (Troullier-Martins) with non linear core correction and Perdew-Burke-Ernzerhof GGA exchange-correlation functional were employed, in the framework of a DFT plane-wave scheme. We inserted increasing concentrations of interstitial H atoms in the hcp Mg lattice, in both tetrahedral and octahedral positions. We calculated the heat of solution and the volume variation as a function of H concentration. Although the difference in Gibbs free energy is positive at any H concentration above 10−6 at.%, our results show that the enthalpic contribution is negative at any H concentration, therefore locally favouring H clustering. This reflects the existence of a driving force for the subsequent formation of the hydride. The volume deformation was characterized, finding that octahedreal interstitials have a minor effect, while tetrahedral interstitial can induce very large local expansion.

scholarly journals Advanced Mechanical and Corrosion Properties of WE43 Alloy Prepared by Powder Metallurgy

2018 ◽  
Vol 134 (3) ◽  
pp. 748-752 ◽  
Author(s):  
D. Dvorský ◽  
J. Kubásek ◽  
D. Vojtěch ◽  
M. Čavojský
Keyword(s):  
Powder Metallurgy ◽  
Corrosion Properties ◽  
Mechanical And Corrosion Properties ◽  
We43 Alloy

scholarly journals Precipitation Hardening on Mechanical and Corrosion Properties of Extruded Mg10Gd Modified with Nd and La

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 640 ◽  
Author(s):  
Petra Maier ◽  
Maximilian Bechly ◽  
Chamini Mendis ◽  
Norbert Hort
Keyword(s):  
Grain Size ◽  
Precipitation Hardening ◽  
Volume Fraction ◽  
Alloying Elements ◽  
Corrosion Properties ◽  
Grain Boundary Mobility ◽  
Initiation And Propagation ◽  
Improve Fracture Toughness ◽  
Mechanical And Corrosion Properties ◽  
Low Solubility

To improve the mechanical and corrosion properties of Mg10Gd, Nd and La are added, and from that, the influence of precipitation hardening was studied. An increase in strength, by decreasing grain size and increasing the volume fraction of Rare Earth-rich precipitates, has been found when increasing the amount of alloying elements. Alloys containing La appear less ductile. Where crack propagation is studied using 3-point bending on Mg10Gd and Mg10Gd1Nd, the failure is mostly driven by twinning; the alloys with La show suppressed twinning, but crack initiation and propagation is caused by brittle and coarse precipitates. Precipitation hardening did not improve fracture toughness and was mostly based on strong grain growth and low solubility of La in Mg. With added alloying elements, the grain size was found to be slightly smaller in the T6 condition—precipitates seem to pin grain boundaries and therefore limit grain boundary mobility. Alloys containing Nd showed the best precipitation hardening response. Corrosion behavior, investigated by voltammetry and immersion, showed the best behavior in the precipitation-hardened condition. Corrosion rates and surface morphology are used to discuss corrosion properties.

Study of the Formation of Long Period Stacking Ordered Phases in Sputtered Thin Film Mg-Gd-Zn Alloys

2017 ◽  
Author(s):  
Sergey Yarmolenko ◽  
Kevin Galdamez ◽  
Sudheer Neralla ◽  
Zhigang Xu ◽  
Devdas Pai ◽  
...  
Keyword(s):  
Thin Film ◽  
Deposition Temperature ◽  
Mg Alloys ◽  
Alloying Elements ◽  
Crystallographic Structure ◽  
Corrosion Properties ◽  
Long Period ◽  
Ordered Phases ◽  
Mechanical And Corrosion Properties ◽  
Structure Patterns

Formation of long-period stacking ordered (LPSO) phases can significantly improve mechanical and corrosion properties of Mg-alloys. Typically LPSO phases can be formed by quick solidification of Mg-alloys having at least two alloying elements with atomic radii higher and lower than that of Mg. Stability of LPSO phases greatly depend on amounts and ratio of alloying elements. We report formation of thin film LPSO structures produced by co-sputtering of magnesium with zinc and gadolinium having less than 10% of alloying elements. This method allows controlling the ratio of the elements in composition, deposition temperature and orientation of thin films. Pure Mg, Zn and Gd films and their alloys deposited at temperatures below 200°C have HCP Mg-based crystallographic structure with exclusively basal orientation. LPSO phases and their stacking period were detected by observation of laminar structure patterns in low-angle x-ray reflectometry scans. The study of effects of elemental composition, deposition temperature and post-annealing of room temperature-deposited films on the formation of LPSO phase showed that the co-sputtering method can be very useful and efficient for the screening of new LPSO phases without the considerable expense preparation of bulk alloy preparation.

Improvement of monitoring of tertiary filtration with particle counting

2006 ◽  
Vol 6 (1) ◽  
pp. 1-9
Author(s):  
V. Miska ◽  
J.H.J.M. van der Graaf ◽  
J. de Koning
Keyword(s):  
Particle Surface ◽  
Minor Effect ◽  
Particle Size Distributions ◽  
Particle Volume ◽  
Mass Distributions ◽  
Particle Counting ◽  
Total Particle ◽  
Particle Counts ◽  
A Minor ◽  
Sample Dilution

Nowadays filtration processes are still monitored with conventional analyses like turbidity measurements and, in case of flocculation–filtration, with phosphorus analyses. Turbidity measurements have the disadvantage that breakthrough of small flocs cannot be displayed, because of the blindness regarding changes in the mass distributions. Additional particle volume distributions calculated from particle size distributions (PSDs) would provide a better assessment of filtration performance. Lab-scale experiments have been executed on a flocculation–filtration column fed with effluent from WWTP Beverwijk in The Netherlands. Besides particle counting at various sampling points, the effect of sample dilution on the accuracy of PSD measurements has been reflected. It was found that the dilution has a minor effect on PSD of low turbidity samples such as process filtrate. The correlation between total particle counts, total particle volume (TPV) and total particle surface is not high but is at least better for diluted measurements of particles in the range 2–10 μm. Furthermore, possible relations between floc-bound phosphorus and TPV removal had been investigated. A good correlation coefficient is found for TPV removal versus floc-bound phosphorus removal for the experiments with polyaluminiumchloride and the experiments with single denitrifying and blank filtration.

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