Chapter 4
Compressive Behavior of AlSiMg0.5Mn Matrix Syntactic Foam
Produced via Thixoinfiltration of Fly Ash Micro Balloons
J. P. Paschoal, R. C. Moraes, E. Bayraktar, J. Sartori, R. Silva, and F. Gatamorta
Abstract Aluminum matrix syntactic foams (AMSF’s) may perform an important role on aerospace and automobile industry
duo to its features like low density, good specific stiffness, vibration damping and high energy absorption efficiency.
AlSiMg0.5Mn matrix syntactic foam was produced by thixoinfiltration of fly ash micro balloons. Expectometry, DSC and
Thermo-Calc analysis were conducted prior the synthesis of the foam to comprehend the aluminum alloy thixoability.
Compressive tests, SEM analysis and x-ray microtopography (Micro CT) were performed to investigate the compressive
characteristics and failure mechanisms of the composite. The compressive tests showed an usual foam behavior with a plato
and a compressive offset stress of 40.5 MPa. The Micro CT analysis confirmed a homogeneous densification resulting in a
high energy absorption capacity.
4.1 Introduction
Due to the intense development of engineering materials, specific classes of materials emerged, such as porous or cellular
metals, classes which metal foams are part of. These materials are characterized by having a large amount of voids being apart
by metal walls. This particular constitution provides a specific combination of properties that cannot be obtained from a single
conventional material [1].
As a special class of aluminum foams, aluminum matrix syntactic foams (AMSFs) appear, which can be defined as
structural materials with pores, in which porosity is guaranteed by the incorporation of hollow spheres or balloons and
homogeneously dispersed in the metallic matrix. Consequently, between the aluminum matrix and balloons an interface can
be formed, being cohesive, if there is a chemical reaction between these constituents or adhesive providing mechanical
anchoring. This interface layer allows the transfer of stress between the composite matrix and the hollow spheres. AMSFs
have as an attractive feature, the possibility of varying the mechanical properties of the product in wide ranges, through the
selection of the matrix material and the volumetric fraction, dimensions and composition of the hollow balloons. In addition,
like other metallic foams, AMSFs have good specific mechanical properties and are isotropic, unlike conventional metallic
foams produced in the liquid state, due to the lack of gravitational force effects, which play a crucial role in the purely gaseous
pore geometry [2].
Composites with metallic matrix reinforced with ceramic particles can present high specific strength, stiffness, resistance to
wear, fatigue, corrosion and creep, depending on the type of reinforcement particles and their volumetric fractions in the
material. These materials, such as syntactic foams, have gained an important space in the aerospace, defense and automobile
industries, in addition to applications as lightweight structures [3].
J. P. Paschoal · J. Sartori · R. Silva
Federal University of Technology-Paraná, Campus Cornélio Procópio, UTFPR-CP/PPGEM, Cornélio Procópio, PR, Brazil
e-mail: joaosartori@utfpr.edu.br; rodrigolopes@utfpr.edu.br
R. C. Moraes · F. Gatamorta
University of Campinas, UNICAMP/FEM-Department of Materials, Campinas, SP, Brazil
e-mail: fabiog@fem.unicamp.br
E. Bayraktar (*)
University of Campinas, UNICAMP/FEM-Department of Materials, Campinas, SP, Brazil
Supmeca -Paris, Mechanical and Manufacturing Engineering School, Paris, France
e-mail: bayraktar@supmeca.fr
© The Society for Experimental Mechanics, Inc. 2021
R. P. Singh, V. Chalivendra (eds.), Mechanics of Composite, Hybrid and Multifunctional Materials, Volume 6,
Conference Proceedings of the Society for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-59868-6_4
19
Compressive Behavior of AlSiMg0.5Mn Matrix Syntactic Foam
Produced via Thixoinfiltration of Fly Ash Micro Balloons
J. P. Paschoal, R. C. Moraes, E. Bayraktar, J. Sartori, R. Silva, and F. Gatamorta
Abstract Aluminum matrix syntactic foams (AMSF’s) may perform an important role on aerospace and automobile industry
duo to its features like low density, good specific stiffness, vibration damping and high energy absorption efficiency.
AlSiMg0.5Mn matrix syntactic foam was produced by thixoinfiltration of fly ash micro balloons. Expectometry, DSC and
Thermo-Calc analysis were conducted prior the synthesis of the foam to comprehend the aluminum alloy thixoability.
Compressive tests, SEM analysis and x-ray microtopography (Micro CT) were performed to investigate the compressive
characteristics and failure mechanisms of the composite. The compressive tests showed an usual foam behavior with a plato
and a compressive offset stress of 40.5 MPa. The Micro CT analysis confirmed a homogeneous densification resulting in a
high energy absorption capacity.
4.1 Introduction
Due to the intense development of engineering materials, specific classes of materials emerged, such as porous or cellular
metals, classes which metal foams are part of. These materials are characterized by having a large amount of voids being apart
by metal walls. This particular constitution provides a specific combination of properties that cannot be obtained from a single
conventional material [1].
As a special class of aluminum foams, aluminum matrix syntactic foams (AMSFs) appear, which can be defined as
structural materials with pores, in which porosity is guaranteed by the incorporation of hollow spheres or balloons and
homogeneously dispersed in the metallic matrix. Consequently, between the aluminum matrix and balloons an interface can
be formed, being cohesive, if there is a chemical reaction between these constituents or adhesive providing mechanical
anchoring. This interface layer allows the transfer of stress between the composite matrix and the hollow spheres. AMSFs
have as an attractive feature, the possibility of varying the mechanical properties of the product in wide ranges, through the
selection of the matrix material and the volumetric fraction, dimensions and composition of the hollow balloons. In addition,
like other metallic foams, AMSFs have good specific mechanical properties and are isotropic, unlike conventional metallic
foams produced in the liquid state, due to the lack of gravitational force effects, which play a crucial role in the purely gaseous
pore geometry [2].
Composites with metallic matrix reinforced with ceramic particles can present high specific strength, stiffness, resistance to
wear, fatigue, corrosion and creep, depending on the type of reinforcement particles and their volumetric fractions in the
material. These materials, such as syntactic foams, have gained an important space in the aerospace, defense and automobile
industries, in addition to applications as lightweight structures [3].
J. P. Paschoal · J. Sartori · R. Silva
Federal University of Technology-Paraná, Campus Cornélio Procópio, UTFPR-CP/PPGEM, Cornélio Procópio, PR, Brazil
e-mail: joaosartori@utfpr.edu.br; rodrigolopes@utfpr.edu.br
R. C. Moraes · F. Gatamorta
University of Campinas, UNICAMP/FEM-Department of Materials, Campinas, SP, Brazil
e-mail: fabiog@fem.unicamp.br
E. Bayraktar (*)
University of Campinas, UNICAMP/FEM-Department of Materials, Campinas, SP, Brazil
Supmeca -Paris, Mechanical and Manufacturing Engineering School, Paris, France
e-mail: bayraktar@supmeca.fr
© The Society for Experimental Mechanics, Inc. 2021
R. P. Singh, V. Chalivendra (eds.), Mechanics of Composite, Hybrid and Multifunctional Materials, Volume 6,
Conference Proceedings of the Society for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-59868-6_4
19