Processing and Characterization of Dual Phase Steel Foams Featured by Different Pore Distribution (original) (raw)

Processing and characterization of dual phase steel foam

Matéria (Rio de Janeiro), 2010

Porous materials featuring cellular structures are known to have many interesting combinations of physical and mechanical properties. Some of them have been extensively used in the transportation field (i.e. balsa wood). Steel foams presented promising theoretical properties for both functional and structural applications in transportation, but processing of such a kind of foams is complex due to their high melting point. Recently a technique for processing Cu-based alloys open-cell foams through the molten metal infiltration of a leachable bed of amorphous SiO 2 particles was proposed. A variation of the proposed technique that uses SiC particles as space holder is now presented and was recently successfully applied for dual phase steel foam processing. Results from a processing of dual phase DP500 steel foams, including some morphological, micro-structural and mechanical characterization, are here presented.

Review Steel foam for structures: A review of applications, manufacturing and

The objective of this paper is to provide a state-of-the-art review for the structural application, manufacturing, material properties, and modeling of a new material: steel foam. Foamed steel includes air voids in the material microstructure and as a result introduces density as a new design variable in steel material selection. By controlling density the engineering properties of steel components may be altered significantly: improvement in the weight-to-stiffness ratio is particularly pronounced, as is the available energy dissipation and thermal resistivity. Full-scale applications of steel foams in civil structures have not yet been demonstrated. Therefore, existing applications demonstrating either proof-of-concept for steel foam, or full-scale use of aluminum foams in situations with clear civil/structural analogs are highlighted. Adoption of steel foam relies on the manufacturing method, particularly its cost, and the resulting properties of the steel foam. Therefore, published methods for producing steel foam are summarized, along with measurements of steel foam structural (modulus, yield stress, etc.) and non-structural (thermal conductivity, acoustic absorption, etc.) properties. Finally, existing models for predicting foamed steel material properties are summarized to highlight the central role of material density. Taken in total the existing research demonstrates the viability of steel foams for use in civil/structural applications, while also pointing to areas where further research work is required.

Mass-scale processing of open-cell metallic foams by pressurized casting method

Here, we report a simple and cost-effective technique for mass-scale processing of open-cell foams of metals and alloys with precise control over foam parameters (pore size, pore distribution, and strut thickness). The process involves pressurized infiltration of molten metals/ alloys into salt preforms under 1.5–4 bar inert gas pressure. The preforms were fabricated from spherical particles of different salts, selected on the basis of the melting temperature of the metals/alloys. The porous metallic structures were recovered by leaching out the salt patterns. The working temperature and the applied pressure play the most vital role in determining the foam structure. The developed foams were studied with optical microscope, scanning electron microscope (SEM), and X-ray computed tomography (CT). Mechanical properties of the developed foams evaluated under quasi-static compressive loading are also reported.

Performance of stainless steel foams produced by infiltration casting techniques

Ferritic (AISI 430) and austenitic (AISI 304) stainless steel foams were produced exploiting a process based on molten metal infiltration on ceramic model. In particular, SiC foundry filter was used as space holder and, after the solidification, it has been removed by hydrofluoric acid. The produced foams are featured by three different porosity grades (10, 20 and 30 PPI) and by constant relative density (0.60). The morphology, the mechanical properties and the corrosion resistance were studied and the results were correlated to the material, the porosity, the size and the distribution of the voids. Morphologically, the structure is arboreous open-cell foam featured by interconnected cavities. This aspect, combined with the high relative density, assures high compressive plateau stress, structural integrity and good deformability. The corrosive tests, according to the ASTM A262-Met.B and NACE TM-0284, permitted to identify possible application fields for these products

Composite metal foams processed through powder metallurgy

Materials & Design, 2008

A new closed cell composite metal foam has been produced using a powder metallurgy technique. The composite foams are processed by filling the vacancies between densely packed steel hollow spheres with steel powder and sintering them into a solid cellular structure. Three sets of samples have been processed, two of carbon steel and one of stainless steel. The relative densities of the products were in the range of 32.4-38.9%. Although denser than other foams, the materials developed in this study display superior compressive strengths and energy absorption capabilities, which caused superior strength to density ratios in our samples compared to other foams made from similar materials. The plateau strength to density ratio for the carbon steel samples were in the range of 12-31.9 MPa/(g/cm 3 ) and for stainless steel samples 43.7 MPa/(g/cm 3 ). The energy absorption at densification for carbon steel samples ranged from 18.9 to 41.7 MJ/m 3 and for the stainless steel sample 67.8 MJ/m 3 .

Characterization of Steel Foams for Structural Components

Metals, 2012

Experimentally measured mechanical properties of hollow sphere steel foam are the subject of this paper. The characterization of the hollow sphere foam encompasses compressive yield stress and densification strain, compressive plastic Poisson's ratio, and compressive unloading modulus, as well as tensile elastic modulus, tensile unloading modulus, tensile yield stress, and tensile fracture strain. Shear properties are also included. These tests provide sufficient information to allow calibration of a macroscopic, continuum constitutive model. Calibrated foam plasticity parameters are tabulated, and unique feature of foam plasticity are explained. Also, initial development of mesoscale simulations, which explicitly model voids and sintered hollow spheres, is reported. This work is part of a larger effort to help the development of steel foam as a material with relevance to civil engineering applications.

A study on processing of a composite metal foam via casting

Materials Science and Engineering: A, 2005

The research sited in this paper involves the development of a new closed cell composite metal foam using gravity casting techniques. The foam is comprised of steel hollow spheres packed into a random dense arrangement, with the interstitial space between spheres infiltrated with a casting aluminum alloy. The measured density of the material is 2.4 g/cm 3 , with a relative density of 41.5%. The composite foam developed in this study displayed superior compressive strength and energy absorption capacity. The compressive strength averaged 67 MPa over a region of 10-50% strain, densification began at approximately 50% strain, and the energy absorption at 50% strain is 30 MJ/m 3 . Scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) compositional analysis affirmed the presence of expected phases in the hollow spheres and aluminum matrix. This novel material has promising applications in the aerospace, automotive, and biomedical industries.