Predicting the Influence of Microporosity on the Mechanical Properties and Fracture Behavior of High-Pressure Die-Cast AM50 Magnesium Alloy

2014 ◽  
Vol 670-671 ◽  
pp. 90-94
Author(s):  
X. Sun ◽  
Z.Y. Cao ◽  
H.F. Liu ◽  
W. Jiang ◽  
L.P. Liu
Keyword(s):  
High Pressure ◽  
Stress Field ◽  
Tensile Properties ◽  
Fracture Behavior ◽  
Numerical Models ◽  
Equivalent Stress ◽  
Die Cast ◽  
Areal Fraction ◽  
Am50 Alloy ◽  
Power Law Equation

In this paper, experimental and finite element modeling methods were adopted to investigate the effects of microporosity on the tensile properties and fracture behavior of high-pressure die-casting (HPDC) AM50 alloy. By specimen-to-specimen fractographic analysis, the variability in tensile properties could be quantitatively correlated with the areal fraction of the porosity presented in the corresponding fracture surfaces by using a simple power law equation. Numerical models of synthetic microstructures with different pore sizes, areal fractions of pores and pore distributions were established. Based on the experimental and numerical simulation results, it could be concluded that the fracture will initially occur in the region where has the highest intensity of equivalent stress field (i.e., contains the most highly localized cluster of pores and shrinkage), and then, fracture crack will fast propagate through the adjacent regions which have the relatively high intensity of stress field.

Effect of Microporosity on the Tensile Properties of High-Pressure Die-Cast AM50 Magnesium Alloy

2014 ◽  
Vol 1033-1034 ◽  
pp. 824-828
Author(s):  
X. Sun ◽  
Zhan Yi Cao ◽  
Hai Feng Liu ◽  
W. Jiang ◽  
L.P. Liu
Keyword(s):  
High Pressure ◽  
Tensile Properties ◽  
Large Variability ◽  
Die Cast ◽  
Fracture Crack ◽  
Areal Fraction ◽  
Cast Magnesium Alloys ◽  
Am50 Alloy ◽  
Cast Magnesium ◽  
Power Law Equation

Cast Magnesium alloys often exhibit large variability in fracture related properties such as ductility. In this study, the characteristics of micro-voids in high-pressure die-cast (HPDC) AM50 alloy were investigated by microstructural detecting. Specimen-to-specimen fractographic analysis of tensile fractured surface was executed to summarize the relation between microporosity and tensile properties. The results indicated that the variability in tensile properties is quantitatively correlated to the areal fraction of porosity in the corresponding fracture surface, which could be expressed by a power law equation. All the results proved that the most highly localized cluster of micro-voids is most preferentially to be the origin of fracture, and then, fracture crack will preferentially propagate through the adjacent regions that with large porosity.

The Effect of Low-Temperature Ageing on the Tensile Properties of High-Pressure Die-Cast Mg-Al Alloys

2013 ◽  
pp. 295-300 ◽  
Author(s):  
A L Bowles ◽  
T J Bastow ◽  
C J Davidson ◽  
J R Griffiths ◽  
P D D Rodrigo
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Tensile Properties ◽  
Al Alloys ◽  
Die Cast ◽  
Temperature Ageing

Microstructure and Mechanical Properties of Low Pressure Die Cast AM50 Magnesium Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 167-170 ◽  
Author(s):  
Li Ming Peng ◽  
Peng Huai Fu ◽  
Hai Yan Jiang ◽  
Chun Quan Zhai
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Die Casting ◽  
Low Pressure ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated ◽  
Die Cast ◽  
Second Phases ◽  
Am50 Alloy ◽  
Pressure Die Casting

Compact AM50 alloy components were cast by Low Pressure Die Casting (LPDC) process. The microstructure and mechanical properties of cast components were investigated under as-cast and heat treated states. It was found that the microstructure of LPDC AM50 is composed of α-Mg and second phases - Mg17Al12 and Al8Mn5. Compared with Gravity die casting, LPDC AM50 alloy had much coarser grains and higher density, with smaller sizes and less content of second phases. The density of AM50 alloy by LPDC process was ρ=1.7836g/cm3, with increase of 0.45% based on Gravity die casting and much more increase compared with high pressure die casting. The as-cast mechanical properties by LPDC process were: σ0.2=57.8Mpa, σb=192.3Mpa, δ=8.7%. These of Gravity die casting were: σ0.2=53Mpa, σb=173.4Mpa, δ=8.1%. UTS in LPDC increased about 20MPa, with better YTS and Elongation. Compared with that of high pressure die cast AM50, the YTS of LPDC was much lower, with comparable UTS and Elongation. The mechanical properties of the heat treated AM50 alloy were still in the same level of as-cast state. AM50 alloy by LPDC process is not necessary subjected to tempering treatment.

Influence of cerium additions on the corrosion behaviour of high pressure die cast AM50 alloy

2012 ◽  
Vol 65 ◽  
pp. 145-151 ◽  
Author(s):  
Faruk Mert ◽  
Carsten Blawert ◽  
Karl Ulrich Kainer ◽  
Norbert Hort
Keyword(s):  
High Pressure ◽  
Corrosion Behaviour ◽  
Die Cast ◽  
Am50 Alloy

Thermo-Structural Analysis of a Micro Gas Turbine Jet- and Recirculation- Stabilized Combustion Chamber

2020 ◽  
Author(s):  
Daniele Cirigliano ◽  
Felix Grimm ◽  
Peter Kutne ◽  
Manfred Aigner
Keyword(s):  
Fluid Dynamics ◽  
High Pressure ◽  
Structural Analysis ◽  
Combustion Chamber ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Numerical Models ◽  
Equivalent Stress ◽  
Heat Fluxes ◽  
Finite Elements Analysis

Abstract Modern Micro Gas Turbines must be capable to operate at different load points, in order to fulfill the demand of Combined Heat and Power for which they are designed. The combustion chamber structures are therefore subjected to regularly variable thermal loads, yet remaining physically constrained at the rest of the structure. Hence, they experience variable metal temperatures, temperature gradients and thermal stresses which can lead to thermal failure. Typical failure mechanisms in combustion chambers are fatigue and creep. Oxidation can also play an important role. In the present study, Computational Fluid Dynamics methods are used for validation of flow prediction, combustion and heat transfer of an atmospheric combustion chamber. Convective and radiative heat losses towards the ambient are specifically taken into account, leading to better agreement with experimental data from preceding studies. The comparison is presented in this paper. The real-scale machine-operated combustion chamber is then tested at its nominal high-pressure conditions. In this respect, the hereby validated numerical models are employed to simulate the high-pressure operation. A fully coupled Thermo-Structural analysis is performed in order to account for heat fluxes within the solid materials. By so doing, wall temperature distributions can be obtained. The results from Fluid Dynamics simulations serve as input for a Finite Elements Analysis, which provides equivalent stress, strain and deformation distributions by using a linear elastic mechanical model. Such distributions highlight the most critical areas, allowing a first estimate of the components’ life according to thermo-mechanical fatigue. The additional influence of Creep and Oxidation is currently under development at DLR Stuttgart and will be presented in subsequent works.

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