Small punch testing method for the development of functionally gradient materials.

Crystal structure and mechanical properties of La 2 NiO 4+δ were measured by high temperature X-ray diffractometry and in-situ small punch test as a function of temperature and oxygen partial pressure. As P(O 2 ) increases, the lattice parameter perpendicular to the perovskite layer increases and that parallel to the layer slightly decreases, and the lattice volume slightly increases. Apparent and true thermal expansion coefficients were calculated from the variation of the lattice constants. The elastic modulus and the fracture strength become larger at higher P(O 2 ) condition. This may be caused by the structural change due to excess oxygen.

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“…Equations 2 and 3 are derived from the finite element method (7). In this study, υ is assumed to be zero since the specimen is thin enough.…”

Section: Methodsmentioning

confidence: 99%

Oxygen Nonstoichiometry, Crystal Structure, and Mechanical Properties of La₂NiO_4+δ

Nakamura¹,

Takeyama²,

Watanabe³

et al. 2009

ECS Trans.

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“…Deformation and stress analysis for SP tests have been performed using an element method (FEM), assuming liner elastic response of the material (9) . In this study, the numerical data were used to compute Young's modulus and to construct stress-normalized displacement diagram.…”

Section: Evaluation Methodsmentioning

confidence: 99%

“…In this study, we have successfully produced binder-free SWCNT solids with purified SWCNTs by using a spark plasma sintering (SPS) method (8) , and the mechanical properties of the disk specimens were investigated by a small punch (SP) testing method (9) . Here, the effects of processing temperatures and pressures on the mechanical properties of the resultant solids were investigated.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of Single-Walled Carbon Nanotube Solids Prepared by Spark Plasma Sintering

Yamamoto

Sato

Takahashi

et al. 2007

JMMP

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In this paper, a spark plasma sintering (SPS) method was employed to solidify single-walled carbon nanotubes (SWCNTs) only, and the effect of processing conditions on the mechanical properties of the SWCNT solids were examined using a small punch (SP) testing method. The sintering temperatures used was in the range of 600~1400˚C, and the sintering pressures used was 40 MPa and 120 MPa. It was demonstrated that the SPS method allowed SWCNTs to be solidified, without any additives. The experimental results showed that the purification of raw soot was critically importance. The SWCNT solids prepared from purified raw soot showed significant non-linear deformation response, producing quasi-ductile fracture behavior. In contrast, raw soot produced brittle solids. The Young's modulus, fracture strength and work of fracture increased with the increasing sintering temperature and pressure. The Raman and SEM analyses showed that the amount of the graphite-like materials were observed to increase with the increasing temperature and pressure, which indicate that the structure of the SWCNTs was changed partially into the graphite-like materials. The formation of graphite-like materials increased tendency of brittle fracture in the SWCNT solids. TEM observations revealed that the fracture surfaces of the SWCNT solids were characterized by pull out of SWCNT bundles. This observation suggests that it may be possible to improve the mechanical properties of SWCNT solids by increasing the cohesion between SWCNTs.

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“…The displacement of the specimen was monitored by the movement of an Al 2 O 3 rod contacting the specimen by laser displacement sensor (KEYENCE, LK-G15 and LK-GD500). According to the following equations (24), σ fSP and E SP were calculated from a load-displacement curve and the specimen dimensions: [3] where P, n, a, t, δ and f (t / a) are puncher load, Poisson's ratio, die radius, specimen thickness, displacement, and adjustment parameter, respectively.…”

Section: Specimen Preparationmentioning

confidence: 99%

High Temperature Strength and Elastic Properties of Doped Ceria under Various Oxygen Partial Pressures

Taguchi¹,

Watanabe

Sato

et al. 2015

ECS Trans.

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Fracture strength and Young's modulus of ceria doped with 10 mol.% Gd and 10, 20 and 30 mol.% Y were investigated by means of small punch testing method under controlled temperature (1073 K) and oxygen partial pressure (log((p(O 2 )/atm)= -1.1, 17.5, -21.4, -22.0). Under the reducing conditions, the color of fractured doped ceria specimen changed from pale yellow to gray; it is therefore indicated that oxygen nonstoichiometry affects mechanical properties of the doped ceria. Under low oxygen partial pressure, Young's modulus of all specimens decreased monotonically. The fracture strength, by contrast, increased at log(p(O 2 )/atm) = -17.5, and lower oxygen partial pressures; each yttria doped ceria with different Y content showed different variation trends. The oxygen partial pressure dependence of the fracture strength of doped ceria could be arranged as a function of the reduction expansion of the lattice constant a/a 0 .

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Small punch testing method for the development of functionally gradient materials.

Cited by 16 publications

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Oxygen Nonstoichiometry, Crystal Structure, and Mechanical Properties of La₂NiO_4+δ

Oxygen Nonstoichiometry, Crystal Structure, and Mechanical Properties of La₂NiO_4+δ

Mechanical Properties of Single-Walled Carbon Nanotube Solids Prepared by Spark Plasma Sintering

High Temperature Strength and Elastic Properties of Doped Ceria under Various Oxygen Partial Pressures

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Small punch testing method for the development of functionally gradient materials.

Cited by 16 publications

References 0 publications

Oxygen Nonstoichiometry, Crystal Structure, and Mechanical Properties of La2NiO4+δ

Oxygen Nonstoichiometry, Crystal Structure, and Mechanical Properties of La2NiO4+δ

Mechanical Properties of Single-Walled Carbon Nanotube Solids Prepared by Spark Plasma Sintering

High Temperature Strength and Elastic Properties of Doped Ceria under Various Oxygen Partial Pressures

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Product

Resources

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Oxygen Nonstoichiometry, Crystal Structure, and Mechanical Properties of La₂NiO_4+δ

Oxygen Nonstoichiometry, Crystal Structure, and Mechanical Properties of La₂NiO_4+δ