Age-Hardening Response of Mg-Al-Sn Alloys

2015 ◽  
Vol 828-829 ◽  
pp. 250-255
Author(s):  
Abu Syed Humaun Kabir ◽  
Jing Su ◽  
Mehdi Sanjari ◽  
In Ho Jung ◽  
Stephen Yue
Keyword(s):  
Electron Microscope ◽  
Aluminum Alloys ◽  
Scanning Electron Microscope ◽  
Magnesium Alloys ◽  
Isothermal Aging ◽  
Precipitation Hardening ◽  
Metallic Alloys ◽  
Mg Alloys ◽  
Age Hardening ◽  
Scanning Electron

Precipitation hardening has been used before as one of the most effective strengthening methods for many metallic alloys. However, this method has not been studied completely in magnesium alloys, and the numbers of precipitation hardenable wrought Mg alloys are still very limited compared to aluminum alloys and steels. The age hardening responses of Mg-Al-Sn alloys in cast-homogenized condition were investigated by isothermal aging at 200°C for prolonged time. It was found that hardness can be improved significantly for the alloy with higher amounts of tin. The improvement in hardness was reasoned by the formation of precipitates. The shapes and morphology of the precipitates were different depending on the orientations of the grains. The precipitates were characterized by scanning electron microscope.

scholarly journals Influence of Multi-Holes on Fatigue Behaviors of Cast Magnesium Alloys Based on In-Situ Scanning Electron Microscope Technology

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1700 ◽  
Author(s):  
Xi-Shu Wang ◽  
Chang-Hao Tan ◽  
Juan Ma ◽  
Xiao-Dong Zhu ◽  
Qing-Yuan Wang
Keyword(s):  
Fatigue Crack ◽  
Electron Microscope ◽  
Crack Initiation ◽  
Scanning Electron Microscope ◽  
Magnesium Alloys ◽  
Mg17al12 Phase ◽  
Cast Magnesium Alloys ◽  
Cast Magnesium ◽  
Scanning Electron

The low cycle fatigue tests on the crack initiation and propagation of cast magnesium alloys with two small holes were carried out by using in-situ scanning electron microscope (SEM) observation technology. The fatigue crack propagation behaviors and fatigue life, which are affected by two small artificial through holes, including the distances between two holes and their locations, were discussed in detail based on the experimental results and the finite element analysis (FEA). The results indicated that the fatigue multi-cracks occurred chiefly at the edges of two holes and the main crack propagation was along the weak dendrite boundary with the plastic deformation vestiges on the surface of α-Mg phase of cast AM50 and AM60B alloys. The fatigue cracking characteristics of cast AZ91 alloy depended mainly on the brittle properties of β-Mg17Al12 phase, in which the multi-cracks occurred still at the edges of two holes and boundaries of β-Mg17Al12 phase. The fatigue crack initiation position of cast magnesium alloys depends strongly on the radius of curvature of through hole or stress concentration factor at the closed edges of two through holes. In addition, the fatigue multi-cracks were amalgamated for the samples with titled 45° of two small holes of cast Mg-Al alloys when the hole distance is less than 4D (D is the diameter of the small hole).

Effects of NaOH Concentration on Properties of Micro Arc Coatings on Magnesium Alloys

2012 ◽  
Vol 482-484 ◽  
pp. 909-913 ◽  
Author(s):  
Shu Fang Zhang ◽  
Rong Fa Zhang ◽  
Wen Kui Li ◽  
Yi Min Zhong
Keyword(s):  
Corrosion Resistance ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Magnesium Alloys ◽  
Environmental Scanning ◽  
Nacl Solution ◽  
Base Solution ◽  
Polarization Test ◽  
Micro Arc Oxidation ◽  
Scanning Electron

Anodic coatings were prepared by micro arc oxidation on AZ91HP in a base solution of 18 g/L Na2SiO3 ּ9H2Oand 4 g/L tannic acid with 5-20 g/l NaOH. The influence of NaOH concentration on final voltage and corrosion resistance were studied. The morphologies of anodic coatings were determined by environmental scanning electron microscope (ESEM). Potentiodynamic polarization test was performed in 3.5wt.% NaCl solution to evaluate the corrosion resistance of anodic coatings. The results show that the NaOH concentration has greatly effect on the final voltage, the compositions, thickness, morphologies and corrosion resistance. The corrosion resistance of anodic coatings is the best in the base solution containing 10 g/l NaOH.

Microstructural Investigations on ATIG and FBTIG Welding of AA 2219 T87 Aluminum Alloy

2014 ◽  
Vol 592-594 ◽  
pp. 489-493 ◽  
Author(s):  
A.V. Santhana Babu ◽  
P.K. Giridharan ◽  
P. Ramesh Narayanan ◽  
S.V.S. Narayana Murty
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Aluminum Alloys ◽  
Scanning Electron Microscope ◽  
Key Words ◽  
Energy Dispersive Spectroscopy ◽  
Welding Process ◽  
Microstructural Investigation ◽  
Cracking Tendency ◽  
Scanning Electron

Limitation in penetration depth is a concern in conventional TIG welding process. To improve penetration capability of TIG process, both Activated TIG (ATIG) and Flux Bounded TIG (FBTIG) are investigated in aluminum alloy AA 2219 T87. Undesirable arc wandering and cracking tendency are observed in ATIG welds. Microstructural investigation reveals ATIG welds are prone for liquation cracks. Morphology of the cracks along with the attributable factors are explained with optical and SEM (Scanning Electron Microscope) micrographs. Energy Dispersive Spectroscopy (EDS) results are also presented to explain the solute enrichment in the grain boundaries of the ATIG welds. FBTIG is found to produce good quality welds and is more suitable for welding aluminum alloys. Key words: Flux Assisted TIG; ATIG; FBTIG; Penetration Improvement; Microstructure; AA2219.

Structure and Property of Ce Conversion Coating on Magnesium Alloys

2012 ◽  
Vol 616-618 ◽  
pp. 1819-1822
Author(s):  
Lu Tie Xu ◽  
Jun Yan ◽  
Yi Guo ◽  
Shi Guo Du
Keyword(s):  
Electron Microscope ◽  
Magnesium Alloy ◽  
Scanning Electron Microscope ◽  
Magnesium Alloys ◽  
Test System ◽  
Conversion Coating ◽  
Electrochemical Test ◽  
Structure And Property ◽  
Corrosion Medium ◽  
Scanning Electron

Ce conversion coating was prepared on the surface of magnesium alloy, and formation of Ce conversion coating was discussed. Structure and resistance to corrosion were measured by scanning electron microscope and electrochemical test system. The results showed the Ce conversion coating was composed of three layers, and it could effectively protect magnesium alloy from corrosion medium.

The Influence of Gd on AM60B Magnesium Alloys' Structures

2013 ◽  
Vol 423-426 ◽  
pp. 207-211
Author(s):  
Jun Feng
Keyword(s):  
Rare Earth ◽  
Electron Microscope ◽  
Energy Spectrum ◽  
Scanning Electron Microscope ◽  
Magnesium Alloys ◽  
Earth Element ◽  
Rare Earth Compounds ◽  
Cast Alloys ◽  
Precipitated Phases ◽  
Scanning Electron

this Paper studies the influence of Gd, a rare-earth element, on AM60B Mg cast alloys structures and, after the analysis of scanning electron microscope (SEM) and energy spectrum analysis, as well as the observation and analysis of XRD, demonstrates Gd could change the precipitates and precipitated phases of Mg cast alloys. The result shows that the adding of Gd to AM60B alloys may effectively refine the alloys structures and the generation of rare-earth compounds, and be conducive to improving the fracture ways of magnesium alloys.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

The Broad Applications of the Scanning Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 20-21
Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscopy ◽  
Surface Topography ◽  
Great Depth ◽  
Resolving Power ◽  
Depth Of Field ◽  
Pictorial Representations ◽  
Scanning Electron

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.

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