Werkstoffkunde für Ingenieure

Roos, Eberhard; Maile, Karl; Seidenfuß, Michael

doi:10.1007/978-3-662-49532-2

Cited by 22 publications

(18 citation statements)

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“…Contrary to other strengthening techniques which typically result in a drastic decrease of thermal and electrical conductivities, this strategy shows only a slight reduction of conductivities . For pure copper, the calculated values drop from 58 × 10 3 Sm −1 to a theoretical value of 41,7 × 10 3 Sm −1 for an ODS alloy containing 5 vol% Al 2 O 3 …”

Section: Introductionmentioning

confidence: 75%

“…For the marmorate areas to develop, Al 2 O 3 still has to be present as solid matter while Cu has to be molten. The temperature at this state lies in between the melting points of the components

(T_{m, {A l}_{2} {normalO}_{3}}

= 2150 °C, T m,Cu = 1083°C). Assuming the temperature is 1400 °C, the surface tension of solid aluminum oxide is 735 J m −2 while that of liquid copper measures 1301 J m −2 .…”

Section: Discussionmentioning

confidence: 99%

“…The wetting angle of liquid copper on solid alumina is 158–170° and thus presents a strong driving force toward demixing since the particles are pushed out of the melt. Furthermore the differing densities of ρ Cu = 9.83 × 103 kg m −3 and ρ Al2O3 = 3.99 × 103 kg m −3 lead to buoyancy of alumina …”

Section: Discussionmentioning

confidence: 99%

“…The outstanding electrical and thermal properties of copper predestine it for implementations such as wiring, switches, or heat exchangers . However, pure copper shows a very high ductility with a Young's modulus of 125 GPa and low hardness of 40–90 HB which prohibit the utilization in mechanically loaded applications …”

Section: Introductionmentioning

confidence: 99%

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Selective Electron Beam Melting of Oxide Dispersion Strengthened Copper

Pobel¹,

Lodes²,

Körner³

2018

Adv Eng Mater

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An oxide dispersion strengthened (ODS) copper powder containing 5 vol% Al 2 O 3 as finely dispersed particles is processed by selective electron beam melting (SEBM), a powder bed based additive manufacturing technology. Contrary to usual powder characteristics used for SEBM, the particles show a non-spherical morphology and a copper oxide layer on their surface. A preheating strategy as well as melting parameters for successful generation of ODS-Cu samples is developed to achieve processability despite the adverse powder conditions. Specimens are built and their meso-and microscale structures are analyzed by optical microscopy (OM) and scanning electron microscopy (SEM) as well as energy dispersive X-ray analyses (EDX). Temperature depending phase separation effects previously encountered in literature during fabrication of ODS-Cu powders are taken into account. [1] Alumina particles were found to coagulate during the process. Partly the Al 2 O 3 was melted and separated from the Cu which resulted in heavy demixing of the system and subsequent loss of dispersion strengthening effect.

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Section: Introductionmentioning

confidence: 75%

(T_{m, {A l}_{2} {normalO}_{3}}

= 2150 °C, T m,Cu = 1083°C). Assuming the temperature is 1400 °C, the surface tension of solid aluminum oxide is 735 J m −2 while that of liquid copper measures 1301 J m −2 .…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Selective Electron Beam Melting of Oxide Dispersion Strengthened Copper

Pobel¹,

Lodes²,

Körner³

2018

Adv Eng Mater

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“…Schaeffler diagram for different sorts of stainless steels containing different amounts of martensitic, ferritic, and austenitic phases depending on the alloying elements used …”

Section: Materials and Designmentioning

confidence: 99%

Challenges of Diffusion Bonding of Different Classes of Stainless Steels

Gietzelt¹,

Toth²,

Huell³

2017

Adv Eng Mater

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Solid state diffusion bonding is used to produce monolithic parts exhibiting mechanical properties comparable to those of the bulk material. This requires diffusion of atoms across mating surfaces at high temperatures, accompanied by grain growth. In case of steel, polymorphy helps to limit the grain size, since the microstructure is transformed twice. The diffusion coefficient differs extremely for ferritic and austenitic phases. Alloying elements may shift or suppress phase transformation until the melting range. In this paper, diffusion bonding experiments are reported for austenitic, ferritic, and martensitic stainless steels possessing varying alloying elements and contents. Passivation layers of different compositions are formed, thus affecting the local diffusion coefficient and impeding diffusion across faying surfaces. As a consequence, different bonding temperatures are needed to obtain good bonding results, making it difficult to control the deformation of parts, since strong nonlinearities exist between temperature, bonding time, and bearing pressure. For martensitic stainless steel, it is shown that it is very easy to obtain good bonding results at low deformation, whereas ferritic and austenitic stainless steels require much more extreme bonding parameters.

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Size effects in the elastic properties of polycrystalline silicon

et al. 2023

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Polycrystalline silicon has a wide range of applications in the semiconductor industry. Instead of components whose dimensions are of the same order of magnitude in all three spatial directions, thin slices are primarily used there. Deviating mechanical properties have been noticed among such thin configurations. In this work, we systematically investigate the size‐dependent effective elastic properties of polycrystalline silicon. This is realized by gradually reducing the thickness of such components, starting from a structure usually referred to as representative volume element. Based on the framework of continuum mechanics, we specify unit cell problems for aggregates whose microstructures are build artificially based on first‐order properties through tessellations. The effective responses of virtual material tests are determined by the aid of the finite element method. Based on a larger number of computational simulations with different but equivalent microstructures, the effective elastic properties of silicon polycrystals are evaluated statistically. The findings are examined with regard to geometrically‐induced symmetries by several methods. For the unconstrained configurations examined here, results show an increase in the scattering of the results where the average stiffness decreases with decreasing structural thickness. These outcomes are also compared to analytical estimates for silicon bulk configurations. This comparison indicates that the average stiffness varies in between a reasonable mean and the isotropic first‐order lower bound of the silicon bulk. Compared to experimental findings, admissible bounds of the stiffnesses are clearly outlined.

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Werkstoffkunde für Ingenieure

Cited by 22 publications

References 0 publications

Selective Electron Beam Melting of Oxide Dispersion Strengthened Copper

Selective Electron Beam Melting of Oxide Dispersion Strengthened Copper

Challenges of Diffusion Bonding of Different Classes of Stainless Steels

Size effects in the elastic properties of polycrystalline silicon

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