Quasi-State Compressive Properties of Functionally Graded Aluminum Matrix Syntactic Foams

2021 ◽  
Vol 1035 ◽  
pp. 878-883
Author(s):  
Ming Ming Su ◽  
Mo Qiu Li ◽  
Thomas Fiedler ◽  
Hai Hao
Keyword(s):  
Volume Fraction ◽  
Hollow Spheres ◽  
Aluminum Matrix ◽  
Stir Casting ◽  
Functionally Graded ◽  
Small Range ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Static Compression ◽  
Plateau Stress

The uniform aluminum matrix syntactic foams (SFs) were prepared by the stir casting method, with alumina hollow spheres (2-3 mm and 3-4 mm) and expanded glass (2-3 mm) as reinforcements, and ZL111 aluminum alloy as matrix. The functionally graded aluminum matrix syntactic foams (FG-SFs) were obtained by superimposing two uniform aluminum matrix syntactic foams. Quasi-static compression tests were performed. The plateau stress of FG-SFs containing only hollow spheres decreased slightly with increasing volume fraction of SF containing 3-4 mm hollow spheres. The FG-SFs containing 2-3 mm hollow spheres and 2-3 mm expanded glass showed the highest plateau stress. The energy absorption behavior of all samples fluctuated in a small range. The initial position of shear band depended on the volume fraction of uniform aluminum matrix syntactic foams, reinforcement type and size. The cracks always appeared first in the uniform aluminum matrix syntactic foams containing expanded glass.

Controlling of Distribution of Mechanical Properties in Functionally-Graded Syntactic Foams for Impact Energy Absorption

2012 ◽  
Vol 706-709 ◽  
pp. 729-734 ◽  
Author(s):  
Masahiro Higuchi ◽  
Tadaharu Adachi ◽  
Yuto Yokochi ◽  
Kenta Fujimoto
Keyword(s):  
Mechanical Properties ◽  
Density Distribution ◽  
Energy Absorption ◽  
Impact Energy ◽  
Volume Fraction ◽  
Functionally Graded ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Density Distributions ◽  
Control Distribution

In the study, novel fabrication processes of functionally-graded (FG) syntactic foams were developed to control distribution of the mechanical properties in the FG foams for highly impact energy absorption. In order to control mechanical properties, the density distributions in FG foams were graded by floating phenomenon of the light-weight micro-balloons in matrix resin during curing process. The density distribution in the foam could be controlled by adjusting the average volume fraction and the turning procedure of the mold before grading the micro-balloons in the foam. The compression tests of the fabricated FG foams suggested that the foams had high absorption of impact energy since the foams collapsed progressively due to the grading of the density distribution.

scholarly journals Characterisation of Hybrid Metal Matrix Syntactic Foams

2015 ◽  
Vol 812 ◽  
pp. 219-225 ◽  
Author(s):  
Imre Norbert Orbulov ◽  
Kornél Májlinger
Keyword(s):  
Volume Fraction ◽  
Mechanical Energy ◽  
Matrix Material ◽  
Hollow Spheres ◽  
Base Material ◽  
Outer Diameter ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Pressure Infiltration ◽  
Geometrical Properties

High quality aluminium matrix syntactic foams (AMSFs) were produced by pressure infiltration. This method can ensure the maximal volume fraction of the reinforcing hollow spheres and very low amount of unwanted or matrix porosities. By this method hybrid MMSFs with mixed metal and ceramic hollow spheres were also produced. The matrix material was AlSi12 alloy and two different types – produced by Hollomet GmbH in Germany – of hollow spheres were used: Globomet (GM) and Globocer (GC). The geometrical properties of the hollow spheres were similar (average outer diameter), but their base material was pure iron and Al2O3+SiO2 in the case of GM and GC hollow spheres respectively. The volume fraction of the reinforcing hollow spheres were maintained at ~65 vol%, but the ratio of them was altered in 20% steps (100% GM + 0% GC, 80% GM + 20% GC...). The results of the compression tests showed, that the compressive strength, yield strength, plateau strength, structural stiffness and the absorbed mechanical energy values increased with higher ceramic hollow sphere reinforcement ratio. The fracture strains of the investigated MMSFs decreased with the higher GC ratio. Generally the strength values also increased with higher diameter to height (H/D) ratio from H/D=1 to H/D=1.5 and 2.

scholarly journals Functionally-Graded Metallic Syntactic Foams Produced via Particle Pre-Compaction

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 314 ◽  
Author(s):  
Thomas Fiedler ◽  
Nima Movahedi ◽  
Lucas York ◽  
Steffen Broxtermann
Keyword(s):  
Syntactic Foam ◽  
Functionally Graded ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Graded Materials ◽  
Static Compression ◽  
X Ray Imaging ◽  
Foam Properties ◽  
A356 Aluminum ◽  
Particle Beds

This paper introduces a novel functionally graded metallic syntactic foam. The investigated foams are manufactured while using infiltration casting where molten A356 aluminum flows into the interstitial voids of packed expanded perlite (EP) particle beds. The partial pre-compaction of particle beds enables the creation of distinct and reproducible density gradients within the syntactic foam. In this study, the samples are produced using four gradually increasing compaction forces and are compared to non-compacted samples. X-ray imaging is used to detect the resulting spatial variation of foam density. In addition, quasi-static compression tests are performed to determine the mechanical foam properties. The results suggest that particle pre-compaction is an efficient tool for tailoring the density and mechanical properties of these novel functionally graded materials.

Microstructure and Compressive Properties of Al/Al2O3 Syntactic Foams

2018 ◽  
Vol 933 ◽  
pp. 174-181 ◽  
Author(s):  
Ming Ming Su ◽  
Han Wang ◽  
Kai Yan Li ◽  
Hai Hao
Keyword(s):  
Hollow Spheres ◽  
Shear Bands ◽  
Syntactic Foam ◽  
Aluminum Matrix ◽  
Strain Curve ◽  
Stir Casting ◽  
Low Density ◽  
Syntactic Foams ◽  
Compressive Properties ◽  
Continuous Contact

Metal matrix syntactic foams with relativity low density (2.03 g/cm3) were prepared by stir casting method. The syntactic foam is comprised of alumina hollow spheres with a diameter range of 1.0-1.5 mm as reinforcement and ZL111 aluminum alloy as matrix. Calcium particles are used to increase the viscosity of the melt to ensure that low density hollow spheres are immersed in the melt. Microstructure characteristics and quasi-static compressive properties of syntactic foams were studied. The hollow spheres were uniformly distributed in the aluminum matrix, and the interface between them was in continuous contact. Compressive stress-strain curve exhibits three distinct stages of deformation: (i) the linear elastic stage; (ii) the plateau area; (iii) final densification stage. The compression strength and plateau stress are 85 MPa and 75 MPa, respectively. The main reasons for the sample failure are the collapse of hollow spheres and the formation of multiple shear bands.

Microstructure and Compression Behavior of Cenosphere Filled Aluminum Syntactic Foams

2012 ◽  
Vol 706-709 ◽  
pp. 704-708
Author(s):  
Qiang Zhang ◽  
Gao Hui Wu
Keyword(s):  
Fly Ash ◽  
Pure Aluminum ◽  
Aluminum Matrix ◽  
High Strength ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Aluminum Foams ◽  
Compression Behavior ◽  
Plateau Stress ◽  
X Ray

Aluminum syntactic foams were fabricated by pressure-infiltrating liquid pure aluminum into packed preforms of cenosphere fly ash. The morphology, true density and porosity of fly ash microballoons were characterized. The microstructure of the syntactic foams demonstrated uniform distribution of the microballoons in the aluminum matrix and seldom infiltration of cenosphere fly ash. These foams were subjected to quasi-static uniaxial compression tests and behaved like high strength aluminum foams under compressive deformation, exhibiting an extended plateau region in the stress–strain curves. With the decreasing of fly ash diameter, the plateau stress and absorbed energy of the syntactic foams increased. X-ray microcomputed tomography was used to examine the foam microstructures after interrupted compression and reveal the damage evolution. The current work provides a better understanding on the structure and mechanical properties of aluminum matrix syntactic foams.

Fabrication of Bulk Functionally-Graded Syntactic Foams for Impact Energy Absorption

2012 ◽  
Vol 706-709 ◽  
pp. 711-716 ◽  
Author(s):  
Tadaharu Adachi ◽  
Masahiro Higuchi
Keyword(s):  
Theoretical Analysis ◽  
Energy Absorption ◽  
Functionally Graded ◽  
Fabrication Process ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Matrix Resin ◽  
Local Fracture ◽  
Density Distributions ◽  
The Matrix

Function of functionally-graded (FG) foams as energy absorption material for impact was discussed on the basis of theoretical analysis, and fabrication process of the foams was proposed in the paper. The FG foams were found to be useful as impact absorber due to progressively local fracture or cushion in the theoretical analysis. Next the fabrication process of the FG foams was suggested. The graded dispersion of the micro-balloons was conducted before curing the matrix resin in the process. The density distributions in the FG foams were confirmed to be predicted by the numerical analysis on the basis of floating the micro-balloons. Finally, compression tests were carried out to evaluate mechanical properties.

scholarly journals Modelling and Experimental Validation of the Porosity Effect on the Behaviour of Nano-Crystalline Materials

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 821
Author(s):  
Panagiotis Bazios ◽  
Konstantinos Tserpes ◽  
Spiros Pantelakis
Keyword(s):  
Numerical Model ◽  
Volume Fraction ◽  
Coarse Grained ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
Static Compression ◽  
Crystalline Materials ◽  
Nano Crystalline ◽  
Porosity Effect ◽  
Grain Diameter

Nano-crystalline metals have attracted considerable attention over the past two decades due to their increased mechanical properties as compared to their microcrystalline counterparts. However, the behaviour of nano-crystalline metals is influenced by imperfections introduced during synthesis or heat treatment. These imperfections include pores, which are mostly located in the area of grain boundaries. To study the behaviour of multiphase nano-crystalline materials, a novel fully parametric algorithm was developed. The data required for implementing the developed numerical model were the volume fraction of the alloying elements and their basic properties as well as the density and the size of randomly distributed pores. To validate the developed algorithm, the alloy composition 75 wt% tungsten and 25 wt% copper was examined experimentally under compression tests. For the investigation, two batches of specimens were used; a batch having a coarse-grained microstructure with an average grain diameter of 150 nm and a nanocrystalline batch having a grain diameter of 100 nm, respectively. The porosity of both batches was derived to range between 9% and 10% based on X-ray diffraction analyses. The results of quasi-static compression testing revealed that the nanocrystalline W-Cu material exhibited brittle behaviour which was characterised by an elastic deformation that led to fracture without remarkable plasticity. A compressive strength of about 1100 MPa was derived which was more than double compared to conventional W-Cu samples. Finite element simulations of the behaviour of porous nano-crystalline materials were performed and compared with the respective experimental compression tests. The numerical model and experimental observations were in good agreement.

Mechanical Properties of Functionally Graded Porous Aluminum Consisting of Pure Aluminum and Al-Mg-Si Aluminum Alloy

2017 ◽  
Vol 741 ◽  
pp. 1-6
Author(s):  
Yoshihiko Hangai ◽  
Tomoaki Morita ◽  
Takao Utsunomiya
Keyword(s):  
Aluminum Alloy ◽  
Pure Aluminum ◽  
Strain Curve ◽  
High Energy ◽  
Functionally Graded ◽  
Compression Tests ◽  
Stress Strain ◽  
Plateau Stress ◽  
Porous Aluminum ◽  
Compression Properties

Porous aluminum can potentially satisfy both the lightweight and high-energy-absorption properties required for automotive components. In this study, functionally graded porous aluminum consisting of pure aluminum and Al-Mg-Si A6061 aluminum alloy was fabricated by a sintering and dissolution process. It was found that functionally graded porous aluminum with the same pore structures but different types of aluminum alloy can be fabricated. By performing compression tests on the fabricated functionally graded porous aluminum, it was found that its stress-strain curve initially exhibited a relatively low plateau stress similar to that of uniform porous pure aluminum. Thereafter, the stress-strain curves exhibited a relatively high plateau stress similar to that of the uniform porous A6061 aluminum alloy. Namely, it was found that the compression properties of porous aluminum can be adjusted and optimized by selecting the appropriate type of aluminum alloy.

Dynamic Compression Behavior of Lotus-Type Porous Iron

2010 ◽  
Vol 658 ◽  
pp. 193-196
Author(s):  
Masakazu Tane ◽  
Tae Kawashima ◽  
Keitaro Horikawa ◽  
Hidetoshi Kobayashi ◽  
Hideo Nakajima
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Testing Machine ◽  
Porous Iron ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Static Compression ◽  
Plateau Stress ◽  
Stress Region ◽  
Quasi Static Compression

Dynamic and quasi-static compression tests were conducted on lotus-type porous iron with porosity of about 50% using the split Hopkinson pressure bar method and universal testing machine, respectively.　In the dynamic compression parallel to the pore direction, a plateau stress region appears where deformation proceeds at nearly constant stress, while the plateau stress region does not appear in the quasi-static compression. The plateau stress region is probably caused by the buckling deformation of matrix iron which occurs only in the dynamic compression. In contrast, the compression perpendicular to the orientation direction of pores exhibits no plateau-stress regions in the both dynamic and quasi-static compression.

scholarly journals Investigation of Wear Behaviour of Al6061 reinforcement with TiC and MoS2

2017 ◽  
Vol 13 (3) ◽  
pp. 32-36
Author(s):  
S. Rajesh ◽  
C. Velmurugan
Keyword(s):  
Wear Resistance ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Aluminum Matrix ◽  
Cost Effective ◽  
Stir Casting ◽  
Wear Behaviour ◽  
Dry Sliding Wear ◽  
Specific Strength ◽  
Main Challenge

Metal matrix composite (MMC) focuses primarily on improved specific strength, high temperature and wear resistance application. Aluminum matrix reinforced with titanium carbide and molybdenum disulfide has good potential and also self-lubrication. The main challenge is to produce this composite in a cost effective way to meet the above requirements. In this study Al–TiC-MoS2 castings with different volume fraction of TiC and MoS2 were produced in an argon atmosphere by an enhanced stir casting method. Hardness of the composite has increased with higher % of TiC addition. At that same time self-lubrication of composite has occur in the effort of MoS2. Dry sliding wear behavior of AMC was analyses with the help of a pin on disc wear and friction monitor. The present analyses reveal the improved hardness  as well as wear resistance.

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