Porous Metal structures made by sintering: processes and applications

Author(s):  
P. Neumann
1998 ◽  
Vol 521 ◽  
Author(s):  
J. Banhart ◽  
J. Baumeister

ABSTRACTThe possibilities for making metallic foams or similar porous metal structures are reviewed. The various processes are classified according to the state of the starting metal - liquid, powdered, ionised. Liquid metal can be foamed directly by injecting gas, gas-releasing foaming agents or by producing supersaturated metal-gas solutions. Indirect methods include investment casting and usage of filler materials. Metal powders can also be used as starting materials for metallic foams: mixtures of such powders with foaming agents are compacted to foamable precursor materials that can be foamed in a second step. Instead of foaming agents inert gas can be directly entrapped in the precursor. Metal foams can also be made from metal powder slurries or by using polymer/powder mixtures. Finally, galvanic electro-deposition also allows to make highly porous metallic structures with open pores.


2011 ◽  
Vol 291-294 ◽  
pp. 3088-3094
Author(s):  
Jin Hui Liu ◽  
Wen Juan Xie ◽  
Qing Song Wei ◽  
Li Wang

Pores are always considered as a kind of defect during manufacturing metal parts via many conventional processes. But porous metals have outstanding physical and mechanical properties which providing them double natures of function and structure, and are applied in many fields of science and technology. Selective laser melting (SLM), developed within current years, has the advantages of producing metal parts with complex structures, and can be used to manufacture complex structures of any kind theoretically. A new method of making porous complicated metal structures via SLM is put forward. Then, the meaning of this method, research advance and future work discussion are presented in this paper, which lays a method foundation for future study and build a new field for both porous metal parts and SLM technology.


2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Adam Mihalko ◽  
Jordan Felice ◽  
Allen Madura ◽  
Davide Piovesan

Additive manufacturing (AM) offers a fabrication process that provides numerous advantages when compared with traditional fabrication methods. Specifically, AM technology allows for the creation of porous media where porosity and permeability can be precisely controlled. When manufacturing metallic artifacts for biomedical use (e.g., bone implants), the investment in a laser sintering machine can be prohibitive for the budget-conscious enterprises limiting the study and use of this technology. Electroforming, electroplating, and electrotyping have been used for decades to replicate the complex shape of unique artifacts and can be viable techniques to create complex metallic shapes starting from a conductive mandrel. We investigated a fabrication technique that combines the stereolithographic additive manufacturing of a polymeric mandrel with electroforming, to obtain porous composites of polymers and metals. The fabrication method to electroform a porous artifact is presented, and an analytical model of the combined properties of the composite material is provided.


Author(s):  
F.-K. Benra ◽  
H. J. Dohmen ◽  
S. Clauss ◽  
J. T. Sehrt ◽  
G. Witt

The characteristic additive build-up at the laser beam melting technology provides the opportunity to freeform porous and defined structures at specific areas in one part. By adjusting the process parameters specific characteristics of the manufactured part such as density, permeability, pore size, porosity and shear strength can be realized. The manufacturing process of a test body is described in detail. The permeability of the manufactured parts is investigated experimentally. In addition a numerical model is build and the flow structure inside of the test body is illustrated. The numerically obtained results are compared to the experimentally obtained results. To show the advantages of this technology for future applications a numerical model of a porous blade surrounded by a hot gas flow and cooled from inside of the porous structure is investigated. The results show that the method to define the characteristics during the laser beam melting process has to be optimized.


Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 554 ◽  
Author(s):  
Marcel Fink ◽  
Olaf Andersen ◽  
Torsten Seidel ◽  
André Schlott

For modern thermal applications, open cell porous metals provide interesting opportunities to increase performance. Several types of cellular metals show an anisotropic morphology. Thus, using different orientations of the structure can boost or destroy the performance in thermal applications. Examples of such cellular anisotropic structures are lotus-type structures, expanded sheet metal, and metal fiber structures. Lotus-type structures are made by casting and show unidirectional pores, whereas expanded sheet metal structures and metal fiber structures are made from loose semi-finished products that are joined by sintering and form a fully open porous structure. Depending on the type of structure and the manufacturing process, the value of the direction-dependent heat conductivity may differ by a factor of 2 to 25. The influence of the measurement direction is less pronounced for the pressure drop; here, the difference varies between a factor of 1.5 to 2.8, depending on the type of material and the flow velocity. Literature data as well as own measurement methods and results of these properties are presented and the reasons for this strongly anisotropic behavior are discussed. Examples of advantageous applications, for example a latent heat storage device and a heat exchanger, where the preferential orientations are exploited in order to gain the full capacity of the structure’s performance, are introduced.


Author(s):  
V. I. Trushlyakov ◽  
◽  
I. Yu. Lesnyak ◽  
V. A. Sevoyan ◽  
◽  
...  

A review of existing methods for drying porous structures including porous metallic materials, is carried out, and a method based on electromagnetic action, in particular, laser radiation, is selected. Recommendations have been developed for physical models of the evaporation process of a model liquid from the developed versions of experimental samples that simulate various investigated porous metallic materials, an experimental stand. A program and methodology have been developed for preliminary experimental studies of the process of exposure to laser radiation on model liquid taking into account the dynamics of the surface and evaporation of model liquid for various experimental samples options including for working out the modes and parameters of laser radiation exposure. Preliminary experimental results have been obtained for the implementation of the developed program of the processes of laser radiation influence on the breast for two variants of experimental samples


2013 ◽  
Vol 51 (10) ◽  
pp. 743-751 ◽  
Author(s):  
Seon-Hui Lim ◽  
Jae-Sung Oh ◽  
Young-Min Kong ◽  
Byung-Kee Kim ◽  
Man-Ho Park ◽  
...  

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