Coextrusion and Mechanical Characterization of Aluminum Coated Mg-Profiles

2013 ◽  
Vol 554-557 ◽  
pp. 767-775 ◽  
Author(s):  
Maik Negendank ◽  
Constanze Weber ◽  
Soeren Mueller ◽  
Walter Reimers
Keyword(s):  
Material Flow ◽  
Noble Metals ◽  
Alloy Coating ◽  
Equilibrium Potential ◽  
Al Alloy ◽  
Forming Process ◽  
Diffusion Layers ◽  
Single Production ◽  
Push Out

Due to their low density and high specific strengths Mg-alloys provide an excellent potential to be used for light weight constructions. However, their equilibrium potential is very low resulting in relatively low corrosion resistance, especially in contact with other, more noble metals. In order to separate Mg from a corrosive environment hybrid billets with Al-alloy coating and AZ31-core were coextruded. Thus, the extrusion and coating of Mg-profiles can be done in a single production step, resulting in aluminum coated Mg-profiles. The influence of the extrusion ratio as well as of different die angles on the formation of diffusion layers at the interface was investigated. Furthermore the phases formed in the diffusion zones were analyzed using EDS and synchrotron XRD. Additionally, FEM-simulations were conducted in order to reveal the material flow of core and shell material during the forming process and to identify differences in using different die angles. The FEM-results were verified by comparison with the real extrusion experiments. Finally, the shear strengths of the produced compounds were evaluated in push-out tests.

scholarly journals Microstructural characterization of accident tolerant fuel cladding with Cr–Al alloy coating layer after oxidation at 1200 °C in a steam environment

2020 ◽  
Vol 52 (10) ◽  
pp. 2299-2305 ◽  
Author(s):  
Dong Jun Park ◽  
Yang Il Jung ◽  
Jung Hwan Park ◽  
Young Ho Lee ◽  
Byoung Kwon Choi ◽  
...  
Keyword(s):  
Coating Layer ◽  
Microstructural Characterization ◽  
Alloy Coating ◽  
Al Alloy ◽  
Fuel Cladding

Low-pressure cold metal spray coatings for repair and protection of marine components

2018 ◽  
Author(s):  
M Pal
Keyword(s):  
Marine Environment ◽  
Alloy Coating ◽  
Al Alloy ◽  
Metallic Coatings ◽  
Material State ◽  
Paint Coatings ◽  
And Performance ◽  
Cuzn Alloy ◽  
Cold Metal ◽  
Metal Spray

The marine environment is hostile to most engineering materials, a combination of in-service wear and exposure to marine environment leads to an accelerated material degradation.  Insufficient or poor protection of the substrates further assists the accelerated material degradation in marine environment. There is a direct relationship between the material-state of a ship and its operational capability, readiness, and service life.  The current state-of-the-art practice is to use paint-based coatings to maintain the material-state of ships.  However, the protection offered by paint coatings is usually brief due to inherent permeability and low damage tolerance of these coatings.  For this reason, the paint coatings require renewal at regular intervals, typically less than 5-years, to maintain a minimum level of protection from the marine environment.  The need for regular painting of ships results in a significant negative impact on the through-life availability, operational capability/readiness, and the cost of maintenance/operation of naval ships.  Therefore, the fleet owners and operators should look beyond the conventional paint-based coatings to achieve significant breakthrough improvements in maintaining and enhancing the material-state of naval ships. Metallic coatings, if selected and applied appropriately, will outperform the paint coatings in the marine environment.  Historically, the cost and performance of metallic coatings, mainly thermal metal spray (TMS) coatings, prevented their widespread use in the marine industry.  The TMS coatings also have their own inherent application and performance related limitations that are widely reported in the literature.  However, the cold metal spray (CMS) coating process can overcome the application and performance related limitations that are typically associated with the TMS coatings, therefore creating an opportunity for widespread use of metallic coatings in shipbuilding and fleet upkeep/maintenance. In this paper, the ability of low-pressure (LP-CMS) coatings to repair and reclaim damaged marine components, and application of functional coatings to improve in-service damage tolerance of the damaged/new components is investigated.  The results of the investigation show that two LP-CMS coatings, Al-alloy and CuZn-alloy, can be used to repair and preserve both new and damaged components.  The accelerated salt-spray and natural immersion corrosion testing of the LP-CMS coatings showed that each coating will be better suited to a particular operational environment, i.e. CuZn-alloy coating performed well in both immersion and atmospheric corrosion environments, whereas Al-alloy coating performed well only in atmospheric corrosion environment. 

scholarly journals Use of Amperometric and Potentiometric Probes in Scanning Electrochemical Microscopy for the Spatially-Resolved Monitoring of Severe Localized Corrosion Sites on Aluminum Alloy 2098-T351

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1132 ◽  
Author(s):  
Rejane M. P. da Silva ◽  
Javier Izquierdo ◽  
Mariana X. Milagre ◽  
Abenchara M. Betancor-Abreu ◽  
Isolda Costa ◽  
...  
Keyword(s):  
Scanning Electrochemical Microscopy ◽  
Oxygen Depletion ◽  
Localized Corrosion ◽  
Alloy Surface ◽  
Al Alloy ◽  
Spatially Resolved ◽  
Lower Oxygen ◽  
Local Ph ◽  
Electrochemical Microscopy

Amperometric and potentiometric probes were employed for the detection and characterization of reactive sites on the 2098-T351 Al-alloy (AA2098-T351) using scanning electrochemical microscopy (SECM). Firstly, the probe of concept was performed on a model Mg-Al galvanic pair system using SECM in the amperometric and potentiometric operation modes, in order to address the responsiveness of the probes for the characterization of this galvanic pair system. Next, these sensing probes were employed to characterize the 2098-T351 alloy surface immersed in a saline aqueous solution at ambient temperature. The distribution of reactive sites and the local pH changes associated with severe localized corrosion (SLC) on the alloy surface were imaged and subsequently studied. Higher hydrogen evolution, lower oxygen depletion and acidification occurred at the SLC sites developed on the 2098-T351 Al-alloy.

scholarly journals Cold Forging Effect on the Microstructure of Motorbike Shock Absorbers Fabricated by Tube Forming in a Closed Die

2021 ◽  
Vol 11 (5) ◽  
pp. 2142
Author(s):  
Trung-Kien Le ◽  
Tuan-Anh Bui
Keyword(s):  
Material Flow ◽  
Cold Forging ◽  
Technological Parameters ◽  
Forming Process ◽  
Tube Forming ◽  
Shock Absorbers ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Quality Of Products ◽  
Forming Defects

Motorbike shock absorbers made with a closed die employ a tube-forming process that is more sensitive than that of a solid billet, because the tube is usually too thin-walled to conserve material. During tube forming, defects such as folding and cracking occur due to unstable tube forming and abnormal material flow. It is therefore essential to understand the relationship between the appearance of defects and the number of forming steps to optimize technological parameters. Based on both finite element method (FEM) simulations and microstructural observations, we demonstrate the important role of the number and methodology of the forming steps on the material flow, defects, and metal fiber anisotropy of motorbike shock absorbers formed from a thin-walled tube. We find limits of the thickness and height ratios of the tube that must be held in order to avoid defects. Our study provides an important guide to workpiece and processing design that can improve the forming quality of products using tube forming.

Characterization of the Effect of Formamide Additive on the Silica Sol-Gel-Glass Forming Process by1H NMR*

1987 ◽  
Vol 153 (Part_1_2) ◽  
pp. 27-36 ◽  
Author(s):  
H. Rosenberger ◽  
H. Bürger ◽  
H. Schütz ◽  
G. Scheler ◽  
G. Maenz
Keyword(s):  
Sol Gel ◽  
Silica Sol ◽  
Forming Process ◽  
Glass Forming

A Study of Strain and Strain-Rate Dependent Properties of a Superplastic Zn-Al Alloy Under Biaxial Stresses

1982 ◽  
Vol 104 (1) ◽  
pp. 41-46
Author(s):  
T. C. Hsu ◽  
I. M. Bidhendi
Keyword(s):  
Strain Rate ◽  
Stress Ratio ◽  
Local Stress ◽  
Biaxial Stress ◽  
Al Alloy ◽  
Local Geometry ◽  
Forming Process ◽  
Rate Dependent ◽  
Strain And Strain Rate ◽  
Liquid Behavior

A superplastic Zn-Al alloy in sheet form is formed into a bulge over a circular hole by pneumatic pressure. The geometry, the stress, the strain, and the strain-rate are determined at various points covering the whole specimen and at various stages of the forming process. The complicated shape, and its complicated changes, are represented by introducing an index for the local geometry, called “prolateness,” which is also related to the local stress ratio in a simple way. The biaxial stress is analyzed into a strain-proportional and a strain-rate-proportional component, which represent, respectively, the quasi-solid and the quasi-liquid behavior of the superplastic material.

Creep characterization of Al alloy thin films for use in MEMS applications

2004 ◽  
Vol 76 (1-4) ◽  
pp. 272-278 ◽  
Author(s):  
R. Modlinski ◽  
A. Witvrouw ◽  
P. Ratchev ◽  
R. Puers ◽  
J.M.J. den Toonder ◽  
...  
Keyword(s):  
Thin Films ◽  
Al Alloy

scholarly journals Material flow control in sheet-bulk metal forming processes using blasted tool surfaces

2018 ◽  
Vol 190 ◽  
pp. 13003 ◽  
Author(s):  
Marion Merklein ◽  
Maria Löffler ◽  
Daniel Gröbel ◽  
Johannes Henneberg
Keyword(s):  
Metal Forming ◽  
Material Flow ◽  
Simultaneous Occurrence ◽  
Tribological Behaviour ◽  
Forming Process ◽  
Functional Elements ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Main Challenge ◽  
Functional Components

Highly-integrated and closely-tolerated functional components can be produced by sheet-bulk metal forming which is the application of bulk forming operations on sheet metals. These processes are characterized by a successive and/or simultaneous occurrence of different load conditions such as stress and strain states which reduce the geometrical accuracy of the functional elements. Thus, one main challenge within sheet-bulk metal forming is the identification of methods to control the material flow and thus to improve the product quality. One suitable approach is to control the material flow by local modifications of the tribological conditions. Within this study requirements regarding the needed adaption of the tribological conditions for a specific sheet-bulk metal forming process were defined by numerical investigations. The results reveal that a local increase of the friction leads to an improved die filling of the functional elements. Based on these results abrasive blasting as a method to modify the tool surface and thus influencing the tribological behaviour was investigated. For the determination of the tribological mechanism of blasted tool surfaces, the influence of different blasting media as well as blasting pressures on the surface integrity and the friction were determined. The correlations between surface properties and friction conditions were used to derive the mechanisms of blasted tool surfaces.

Sign in / Sign up

Export Citation Format

Share Document