Anisotropic Mechanical Properties of Nickel Foams Fabricated by Powder Metallurgy

2008 ◽  
Vol 569 ◽  
pp. 277-280
Author(s):  
Yasuo Yamada ◽  
Takumi Banno ◽  
Yun Cang Li ◽  
Cui E Wen
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Pore Size ◽  
Nickel Foam ◽  
Deformation Behaviour ◽  
Nominal Stress ◽  
Porous Nickel ◽  
Anisotropic Mechanical Properties ◽  
Electron Scanning Microscopy ◽  
Nickel Foams

In the present study, porous nickel foam samples with pore sizes of 20 μm and 150 μm and porosities of 60 % and 70 % were fabricated by the space-holding sintering method via powder metallurgy. Electron scanning microscopy (SEM) and Image-Pro Plus were used to characterise the morphological features of the porous nickel foam samples. The anisotropic mechanical properties of porous nickel foams were investigated by compressive testing loading in different directions, i.e. the major pore axis and minor pore axis. Results indicated that the nominal stress of the nickel foam samples increases with the decreasing of the porosity. Moreover, the foam sample exhibited significantly higher nominal stress for loading in the direction of the major pore axis than loading in direction of the minor pore axis. It is also noticeable that the nominal stress of the nickel foams increases with the decreasing of the pore size. It seems that the deformation behaviour of the foams with a pore size in the micron-order differs from those with a macro-porous structure.

Micro-Porous Nickel Produced by Powder Metallurgy

2007 ◽  
Vol 534-536 ◽  
pp. 977-980
Author(s):  
Yasuo Yamada ◽  
Yun Cang Li ◽  
Takumi Banno ◽  
Zhen Kai Xie ◽  
Cui E Wen
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Porous Structure ◽  
Pore Size ◽  
Cell Structure ◽  
Deformation Behaviour ◽  
Average Pore Size ◽  
Chemical Vapour ◽  
Porous Nickel ◽  
Average Pore

Micro-porous nickel (Ni) with an open cell structure was fabricated by a special powder metallurgical process, which includes the adding of a space-holding material. The average pore size of the micro-porous Ni samples approximated 30 μm and 150 μm, and the porosity ranged from 60 % to 80 %. The porous characteristics of the Ni samples were observed using scanning electron microscopy (SEM) and the mechanical properties were evaluated using compressive tests. For comparison, porous Ni samples with a macro-porous structure prepared by both powder metallurgy (pore size 800 μm) and the traditional chemical vapour deposition (CVD) method (pore size 1300 μm) were also presented. Results indicated that the porous Ni samples with a micro-porous structure exhibited different deformation behaviour and dramatically increased mechanical properties, compared to those of the macro-porous Ni samples.

Mechanical Properties of Micro-Porous Metals Produced by Space-Holding Sintering

2007 ◽  
Vol 29-30 ◽  
pp. 75-78 ◽  
Author(s):  
Takumi Banno ◽  
Yun Cang Li ◽  
Cui E Wen ◽  
Yasuo Yamada
Keyword(s):  
Mechanical Properties ◽  
Cell Structure ◽  
Deformation Behaviour ◽  
Average Pore Size ◽  
Chemical Vapour ◽  
Porous Nickel ◽  
Porous Metals ◽  
Average Pore ◽  
Nickel Foams ◽  
Compressive Tests

Micro-porous nickel foams with an open cell structure were fabricated by the space-holding sintering. The average pore size of the micro-porous nickel specimens ranged from 30 μm to 150 μm, and the porosity ranged from 60 % to 80 %. The porous characteristics of the nickel specimens were observed using scanning electron microscopy (SEM). The mechanical properties were studied using compressive tests. For comparison, macro-porous nickel foams prepared by the chemical vapour deposition method with pore sizes of 800 μm and 1300 μm and porosity of 95 % were also presented. Results indicated that the ratio value of 6 and higher for the specimen length to cell size (L/d) is satisfying for obtaining stable compressive properties. The micro-porous nickel specimens exhibited different deformation behaviour and dramatically increased mechanical properties, compared to those of the macro-porous nickel specimens.

Preparation and characterization of paraffin/nickel foam composites as neutron-shielding materials

2017 ◽  
Vol 52 (7) ◽  
pp. 953-962 ◽  
Author(s):  
Yun Zhang ◽  
Feida Chen ◽  
Xiaobin Tang ◽  
Hai Huang ◽  
Minxuan Ni ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Carbide ◽  
Gamma Ray ◽  
Nickel Foam ◽  
Neutron Shielding ◽  
Static Compression ◽  
Neutron Absorber ◽  
Open Cell ◽  
Foam Composite ◽  
Nickel Foams

Traditional neutron-shielding materials usually have poor mechanical properties and secondary gamma-shielding capability. The new requirements of modern neutron-shielding materials are difficult to satisfy. A paraffin/nickel foam neutron-shielding composite was prepared and characterized in this study. Open-cell nickel foams were fabricated through electrodeposition. Subsequently, the paraffin/nickel foam composite were prepared by filling the open-cell nickel foams with melted paraffin. The intrinsic parameters of nickel foam and the content of neutron absorber (boron carbide) were controlled to optimize the composite. The mechanical properties of the composite were studied through a static compression test. The compressive strength improved to 0.4 times that of the nickel foams. The Am–Be source transmittance experiment showed that the 8 cm thick PFM presented a neutron transmittance of 56.1%, and the 6 cm thick boron carbide/paraffin/nickel foam (PFM-B) presented a neutron transmittance of 37.6%. The paraffin/nickel foam and PFM-B had approximately the same shielding efficiency as paraffin and boron carbide/paraffin, respectively. However, the second gamma ray shielding efficiency of the paraffin/nickel foam and PFM-B was significantly higher than that of paraffin and boron carbide/paraffin. The mechanical properties and secondary gamma ray-shielding capability of the composite can be improved by increasing the relative density of nickel foams.

Effect of Pore Size on Mechanical Properties of Titanium Foams

2010 ◽  
Vol 654-656 ◽  
pp. 827-830 ◽  
Author(s):  
Yang An ◽  
Chun Hui Yang ◽  
Peter D. Hodgson ◽  
Cui E Wen
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Size Effects ◽  
Cell Walls ◽  
Deformation Behaviour ◽  
Pore Sizes ◽  
Geometrical Characteristics ◽  
Titanium Foam ◽  
Scanning Electron ◽  
Compressive Tests

In the study, both experimental work and numerical modeling are performed to investigate the pore size effects on the mechanical properties and deformation behaviours of titanium foams. Cylindrical titanium foam samples with different pore sizes are fabricated through powder metallurgy. Scanning electron microscope (SEM) is used to determine the pore size, pore distribution and the ratios of the length to width of pores. Compressive tests are carried out to determine the mechanical properties of the titanium foams with different pore sizes. Finally, finite element modeling is attempted to simulate the deformation behaviour and the mechanical properties of the titanium foams. Results indicate that titanium foams with different pore sizes have different geometrical characteristics, which lead to different deformation behaviours of cell walls during compression, resulting in different mechanical properties of titanium foams.

An Evaluation of the Wicking Characteristics of Stochastic Open-Cell Nickel Foams

2006 ◽  
Author(s):  
Jessica Sheehan ◽  
Douglas T. Queheillalt ◽  
Pamela M. Norris
Keyword(s):  
Pore Size ◽  
Heat Pipe ◽  
Friction Factor ◽  
Capillary Tube ◽  
Nickel Foam ◽  
Heat Pipes ◽  
Working Fluid ◽  
Open Cell ◽  
Pipe System ◽  
Nickel Foams

Heat pipes are a very efficient device which can be used for the rapid transfer of thermal energy. Small and microscale heat pipes are used in a variety of applications such as electronics and microprocessor coolers. As the size of the heat pipe devices increase, the volume and rate at which the working fluid is replenished in the evaporator region becomes an important parameter influencing the performance of the heat pipe system. Here, a stochastic open-cell nickel-foam has been evaluated for use as the wick material in heat pipes. The pore size of the open-cell nickel foam was modified via compression in the through thickness direction in order to evaluate its wicking characteristics and fluid flow resistance as a function of pore size. These properties are controlled by the effective pore size (controlled via through thickness compression) of the nickel foam. The equilibrium wicking height was measured by a simple flow experiment. The mass flow rate and the differential pressure of the crushed foams were measured at each thickness to generate a friction factor as a function of pore size. The equilibrium wicking height results were compared to a simple analytical model of a single capillary tube and found to be in reasonable agreement and the friction factor followed the same trend as the equilibrium wicking height. The experiments were used to evaluate the suitability of stochastic open cell nickel foams as wicks for heat pipe systems.

Preparation and Characterisation of Open-Cell Microporous Nickel

2007 ◽  
Vol 539-543 ◽  
pp. 1833-1838 ◽  
Author(s):  
Yasuo Yamada ◽  
Takumi Banno ◽  
Zhen Kai Xie ◽  
Yun Cang Li ◽  
Cui E Wen
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Average Pore Size ◽  
Microporous Structure ◽  
Macroporous Structure ◽  
Average Pore ◽  
Open Cell ◽  
Nickel Foams ◽  
Sintering Method ◽  
Compressive Tests

In the present study, nickel foams with an open cell microporous structure were fabricated by the so-called space-holding particle sintering method, which included the adding of a particulate polymeric material (PMMA). The average pore size of the nickel foams approximated 10.5 μm; and the porosity ranged from 70 % to 80 %. The porous characteristics of the nickel foams were observed using scanning electron microscopy and the mechanical properties were evaluated using compressive tests. For comparison, nickel foams with an open-cell macroporous structure (pore size approximately 1.3 mm) were also presented. Results indicated that the nickel foams with a microporous structure possess enhanced mechanical properties than those with a macroporous structure.

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