scholarly journals Analysis of Crystallisation Process of Cast Magnesium Alloys Based on Thermal Derivative Analysis / Analiza Procesu Krystalizacji Odlewniczych Stopów Magnezu W Oparciu O Analizę Termicznoderywacyjną

2015 ◽  
Vol 60 (4) ◽  
pp. 2993-3000 ◽  
Author(s):  
M. Król ◽  
T. Tański ◽  
G. Matula ◽  
P. Snopiński ◽  
A.E. Tomiczek
Keyword(s):  
Magnesium Alloys ◽  
Cooling Curve ◽  
X Ray ◽  
Dendrite Coherency Point ◽  
Derivative Analysis ◽  
Crystallisation Process ◽  
Cast Magnesium Alloys ◽  
Coherency Point ◽  
Dendrite Coherency ◽  
Cast Magnesium

The paper presents the results of the crystallisation process of cast magnesium alloys based on the thermal-derivation analysis. The effects of aluminium content and cooling rate on the characteristic parameters of the evaluation of magnesium dendrites during solidification at different cooling rates were investigated by thermal-derivative analysis (TDA). Dendrite coherency point (DCP) is defined with a new approach based on the second derivative cooling curve. Solidification behaviour was evaluated via one thermocouple thermal analysis method. Microstructural evaluations were characterised by light microscope, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. This research revealed that utilisation of d2T/dt2 versus the time curve methodology allows for analysis of the dendrite coherency point.

Influence of Heat Treatment on Structure and Properties of the Cast Magnesium Alloys

2006 ◽  
Vol 15-17 ◽  
pp. 491-496 ◽  
Author(s):  
Tomasz Tański ◽  
Leszek Adam Dobrzański ◽  
Lubomír Čížek
Keyword(s):  
Heat Treatment ◽  
Chemical Composition ◽  
Magnesium Alloys ◽  
Diffraction Method ◽  
Hardness Measurement ◽  
X Ray ◽  
Qualitative And Quantitative ◽  
Cast Alloys ◽  
Cast Magnesium Alloys ◽  
Cast Magnesium

In this paper is presented the structure and proprieties of the cast magnesium alloys as cast state and after heat treatment cooled with different cooling rate, depending on the cooling medium (furnace, water, air). For investigations samples in shape of 250x150x25 mm plates were used. The presented results concern X-ray qualitative and quantitative microanalysis as well as qualitative and quantitative X-ray diffraction method, tensile tests, hardness measurement. In the analysed alloys a structure of α %solid solution and fragile phase β (Mg17Al12) occurred mainly on grain borders as well as eutectic and phase AlMnFe, Mg2Si. Investigation are carried out for the reason of chemical composition influence and precipitation processes influence to the structure and mechanical properties of the magnesium cast alloys with different chemical composition in as cast alloys and after heat treatment.

Process-Structure-Property Relationships for Magnesium Alloys

2012 ◽  
Vol 706-709 ◽  
pp. 1273-1278 ◽  
Author(s):  
Jonathan P. Weiler ◽  
J.T. Wood ◽  
I. Basu
Keyword(s):  
Magnesium Alloys ◽  
Area Fraction ◽  
Structure Property ◽  
Maximum Area ◽  
X Ray ◽  
Structure Property Relationships ◽  
Die Cast ◽  
Cast Magnesium Alloys ◽  
Cast Magnesium ◽  
Process Structure

Gravity step-casting experiments were performed to investigate process-structure-property relationships in three different die-cast magnesium alloys – AM60, AZ91 and AE44. The step-cast mold was instrumented to capture temperature profiles of the solidification of molten magnesium. This paper investigates the structure-property relationships of these magnesium alloys, specifically the dependence of the fracture properties upon the porosity that forms during the casting process. Sixteen tensile specimens were cut from the step-casting perpendicular to the solidification front, for each alloy examined. Correlations from X-ray tomography data were used to estimate the maximum area fraction of porosity from the average volumetric porosity in the specimens, assuming a typical size and spatial distribution of porosity. This relationship can be used in the absence of more accurate measure of porosity (i.e. serial sectioning, computed x-ray tomography). A failure model for die-cast alloys – which depends upon the strain-hardening coefficient and the maximum area fraction of porosity in the specimen – was used to predict fracture strains for each specimen. The experimental tensile elongation of each specimen was compared with predicted values. The resulting mechanical properties determined from these cast magnesium alloys will be used to develop process-structure-property relationships.

scholarly journals Thermal Assessment of Modified Ultra-Light Magnesium-Lithium Alloys

2017 ◽  
Vol 62 (4) ◽  
pp. 2433-2440 ◽  
Author(s):  
M. Król ◽  
T. Mikuszewski ◽  
D. Kuc ◽  
T. Tański ◽  
E. Hadasik
Keyword(s):  
Grain Size ◽  
Master Alloy ◽  
Cast Alloy ◽  
Solidus Temperature ◽  
X Ray ◽  
Lithium Aluminium ◽  
Derivative Analysis ◽  
Master Alloys ◽  
Crystallisation Process ◽  
Cast Magnesium

AbstractThe paper presents the results of the influence of commercial TiBor and AlSr10 master alloys on the refine the grains size, hardness and crystallisation process based on the thermal-derivation analysis of light cast magnesium-lithium-aluminium alloys. The effects of TiBor and AlSr10 content on the characteristic parameters of the crystallisation process of Mg-Li-Al alloys were investigated by thermal-derivative analysis (TDA). Microstructural evaluations were identified by light microscope, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy.The results showed that the addition of TiBor master alloy reduced the grain size of Mg-9Li-1.5Al cast alloy from 900 μm to 500 μm, while the addition of AlSr10 master alloy reduced the grain size of investigated cast alloy from 900 μm to 480 μm. Moreover, an addition of TiBor and AlSr10 simultaneously reduced the grain size from 900 μm to 430 μm.Results from the thermal-derivative analysis showed that the addition of grain refinement causes a decrease in nucleation temperature and solidus temperature.

Long Term Creep Properties of a Die-Cast Mg-Al-Ca Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 163-166
Author(s):  
Yoshihiro Terada ◽  
Tatsuo Sato
Keyword(s):  
Creep Rate ◽  
Magnesium Alloys ◽  
Cast Alloy ◽  
Rupture Life ◽  
Testing Temperature ◽  
Creep Rupture ◽  
Die Cast ◽  
Cast Magnesium Alloys ◽  
Term Creep ◽  
Cast Magnesium

Creep rupture tests were performed for a die-cast Mg-Al-Ca alloy AX52 (X representing calcium) at 29 kinds of creep conditions in the temperature range between 423 and 498 K. The creep curve for the alloy is characterized by a minimum in the creep rate followed by an accelerating stage. The minimum creep rate (ε& m) and the creep rupture life (trup) follow the phenomenological Monkman-Grant relationship; trup = C0 /ε& m m. It is found for the AX52 die-cast alloy that the exponent m is unity and the constant C0 is 2.0 x 10-2, independent of creep testing temperature. The values of m and C0 are compared with those for another die-cast magnesium alloys. The value m=1 is generally detected for die-cast magnesium alloys. On the contrary, the value of C0 sensitively depends on alloy composition, which is reduced with increasing the concentration of alloying elements such as Al, Zn and Ca.

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).

Properties of Fine-Grained Cast Magnesium Alloys for Sheet Manufacture

2013 ◽  
pp. 223-226 ◽  
Author(s):  
Ulrich Draugelates ◽  
Belkacem Bouaifi ◽  
René Poss ◽  
Claus-C. Kedenburg
Keyword(s):  
Magnesium Alloys ◽  
Fine Grained ◽  
Cast Magnesium Alloys ◽  
Cast Magnesium
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