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.

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.

The Processing and Structure of Steel Matrix Syntactic Foams Prepared by Infiltration Casting

2018 ◽  
Vol 933 ◽  
pp. 129-135
Author(s):  
Quan Zhan Yang ◽  
Yan Peng Wei ◽  
Zhi Quan Miao ◽  
Peng Gao ◽  
Bo Yu
Keyword(s):  
Metal Matrix ◽  
Heat Insulation ◽  
Hollow Spheres ◽  
Syntactic Foam ◽  
Average Diameter ◽  
Steel Matrix ◽  
Syntactic Foams ◽  
Minimum Diameter ◽  
Microstructure Characteristics ◽  
Multifunctional Properties

Metal matrix syntactic foams are consisting of metal matrix and hollow spheres in closely or randomly packed, which own multifunctional properties with lightweight, damping, heat insulation, energy absorption and have a vast application prospect. Steel matrix can extend the potential of syntactic foams as a materials class to several new fields of application. In this paper, the hollow alumina spheres were introduced into the steel matrix by infiltration casting, the minimum diameter of hollow spheres for infiltration is analyzed in theory, the steel matrix syntactic foams were successfully prepared, which contain two different sphere types with average diameter sizes 3.97mm and 4.72mm, and the average densities of syntactic foams were calculated to be 4.39 (spheres occupy 43.7% of the volume) and 3.74 g/cm3 (spheres occupy 52.1% of the volume), respectively. The microstructure characteristics of the steel matrix syntactic foam were analyzed by means of scanning electron microscopy and energy spectrum.

Preparation and Characteristic of Different Hollow Microspheres Filled Syntactic Foams

2014 ◽  
Vol 809-810 ◽  
pp. 237-242
Author(s):  
Xin Jin ◽  
He Yi Ge ◽  
Ping Wang ◽  
Zhong Yuan Pan ◽  
Juan Chen
Keyword(s):  
Interfacial Adhesion ◽  
Syntactic Foam ◽  
Weight Fraction ◽  
Hollow Microspheres ◽  
Syntactic Foams ◽  
Polystyrene Microspheres ◽  
Compressive Properties ◽  
Hollow Glass Microspheres ◽  
Important Improvement ◽  
The Impact

In this study, hollow glass microspheres (HGM) and hollow polystyrene microspheres (HPSM) have been employed as fillers in epoxy resin to prepare the syntactic foam. A kind of good performance composite was prepared. The effects of presence of various hollow microspheres on the impact and compressive properties of syntactic foams are studied. Weight fraction of HPSM and HGM for the syntactic foams varies up to 2.0 wt% and 25 wt%, respectively. The results show that the coupling agent can induce the interfacial adhesion between the HGM and the resin and help HGM uniformly disperse in the resin and hence result in better mechanical properties of composite. On the other hand, the effect of HPSM for the composite density is greater than that of HGM. The addition of a small percentage of HPSM helps produce an important improvement in the low density of syntactic foam. The syntactic foam has uniform stability component and the excellent integrative performances. Fabricated syntactic foams had compression strength of 51.96 MPa and density of 0.671 g/cm3.

Compressive Stress of Syntactic Foam: Effect of rNBR Particles Reinforced Epoxy Macrospheres (rNBR-EM)

2018 ◽  
Vol 280 ◽  
pp. 301-307
Author(s):  
Z. Zakaria ◽  
C.Y. Yao
Keyword(s):  
Compressive Strength ◽  
Physical Properties ◽  
Compressive Stress ◽  
Energy Absorption ◽  
Wall Thickness ◽  
Syntactic Foam ◽  
Radius Ratio ◽  
Butadiene Rubber ◽  
Syntactic Foams ◽  
Compressive Properties

This research focuses on the effect of rejected nitrile butadiene rubber (rNBR) gloves particles reinforced epoxy macrospheres (EM) on the physical properties and compressive stress of syntactic foam. Adding rNBR particles on the surface of macrospheres can increase the energy absorption as a result of improving the compressive properties of syntactic foam. Three types of macrospheres have been produced for the fabrication of syntactic foam, namely EM without rNBR, 1-layer rNBR-EM and 2-layer rNBR-EM. The results showed that increased rNBR particles layer on macrospheres has increased the wall thickness, and reduced the radius ratio of macrospheres as well as increased the density of syntactic foams. The compressive strength and modulus of syntactic foam with 2-rNBR-EM increased compared to the syntactic foams of 1-rNBR-EM and EM without rNBR. In addition, the toughness of the 2-rNBR-EM increased compared to the syntactic foams of 1-rNBR-EM and EM without rNBR.

Analytical and Numerical Study of Crushing of Syntactic Foams Under Uniaxial Compression

2008 ◽  
Author(s):  
Prabhakar Marur
Keyword(s):  
Finite Element ◽  
Uniaxial Compression ◽  
Numerical Study ◽  
Bulk Material ◽  
Hollow Spheres ◽  
Syntactic Foam ◽  
Particulate Composites ◽  
Syntactic Foams ◽  
The Matrix ◽  
Crushing Behavior

Syntactic foams are a class of particulate composites made with hollow microspheres dispersed uniformly in a matrix. By the inclusion of hollow spheres in the matrix, the bulk mechanical properties are improved by limiting the bending of cell edges and localization of inelastic deformation, which is the cause of failure in the case of low-density foams. For the general class of cellular materials, several analytical and experimental methods are available in the literature to characterize the material. In the case of syntactic foams, relatively few methods exist for the computation of effective elastic properties and methods for analyzing the crush behavior of the syntactic foams are rather limited. In this research, the quasi-static crushing behavior of syntactic foam under uniaxial compression is investigated using analytical and numerical methods. To better understand the bulk behavior of syntactic foam, a micromechanical study is conducted to analyze the crushing of hollow spheres in dilute concentration. Initially the stress fields around dilute concentration are derived using continuum mechanics principles and subsequently a limit analysis is performed. To gain further insight into the deformation fields and deformations of cell walls leading to densification, a finite element (FE) analysis is performed. Assuming a periodic repetition of a representative volume of the material would correspond to the bulk material, axisymmetric and 3D finite element models are developed. The numerical computations are compared with the analytical results obtained in this study, and with experimental data reported in the literature. Using the FE models, a parametric study is conducted to investigate the influence of microsphere strength and elastic mismatch between the matrix and the inclusions on the crush behavior of syntactic foam.

scholarly journals Notch (In)Sensitivity of Aluminum Matrix Syntactic Foams

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 574 ◽  
Author(s):  
Attila Szlancsik ◽  
Bálint Katona ◽  
Dóra Károly ◽  
Imre Orbulov
Keyword(s):  
Fracture Toughness ◽  
Crack Opening ◽  
Matrix Material ◽  
Hollow Spheres ◽  
Aluminum Matrix ◽  
Syntactic Foams ◽  
Complex Investigation ◽  
Pressure Infiltration ◽  
Three Point Bending ◽  
The Matrix

Aluminum alloy (Al99.5 or AlSi12)-based metal matrix syntactic foams (MMSFs) were produced by pressure infiltration with ~65 vol % Globocer filler (33 wt % Al2O3, 48 wt % SiO2, 19 wt % Al2O3∙SiO2). The infiltrated blocks were machined by different geometry tools in order to produce notched samples. The samples were loaded in three-point bending, and the loading force values were recorded against the cross-head displacements and the crack opening displacements. To measure up the notch sensitivity and toughness of the MMSFs, the fracture energies and the fracture toughness values were determined. The results showed that the mentioned quantities are needed to describe the behavior of MMSFs. The fracture energies were shown to be notch-sensitive, while the fracture toughness values were dependent only on the matrix material and were insensitive to the notch geometry. The complex investigation of the fracture surfaces revealed strong bonding between the hollow spheres and the Al99.5 matrix due to a chemical reaction, while this bonding was found to be weaker in the case of the AlSi12 matrix. This difference resulted in completely different crack propagation modes in the case of the different matrices.

scholarly journals Effect of Layer Thickness in Layered Aluminum Matrix Syntactic Foam

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4172 ◽  
Author(s):  
Chenhao Qian ◽  
Chen Liang ◽  
Ziyang He ◽  
Weixi Ji
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Syntactic Foam ◽  
Aluminum Matrix ◽  
Peak Stress ◽  
Impact Response ◽  
Syntactic Foams ◽  
Layer Number ◽  
Failure Propagation ◽  
The Impact

This work experimentally investigates the effect of layered structure on the static and impact response of a new layered syntactic foam developed for impact energy absorption. The layered syntactic foam had the same density of 1.6 g/cm3 and the same components of 50% large spheres (L) and 50% small spheres (S) with different structures from two layers to five layers. The impact response and energy absorption were investigated by drop-weight impact tests. Under static loading, more layers led to higher yield stress and lower energy absorption. There were three types of progressive failures of layered syntactic form under impact loading. The failure propagation was examined and found to be dependent on the layer number and impact energy. Interestingly, layered syntactic foam absorbed more energy than both of its components in terms of ductility. The ductility of layered syntactic foam decreased with the increase in layer number. The peak stress of layered syntactic foam increased with the increase in layer number. Two-layered syntactic foam LS had the highest ductility under 60 J/g impact, as well as an energy absorption of 35 J/g, compared to other layered syntactic foams. Specifically, its component L had a ductility under 70 J/g and an energy absorption of 25 J/g, while component S had a ductility under 10 J/g and an energy absorption of 10 J/g.

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