The mechanical size effect as a mean-field breakdown phenomenon: Example of microscale single crystal beam bending

Demir, Eralp; Raabe, Dierk; Roters, Franz

doi:10.1016/j.actamat.2009.11.031

Cited by 84 publications

(43 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Room temperature experiments were performed by Simons et al [4] on copper foils with thicknesses up to 100 µm clearly showing a considerable size effect. Similar results were found by Demir et al [5] on copper single crystals. Albers et al [6] performed numerical examinations by FEA, modeling a microgear tooth with 2-10 grains across the stressed sections.…”

supporting

confidence: 81%

High temperature Gleeble microtensile testing of metallic micro specimens

Kröning

Lang²,

Hofmann

2016

Materials Testing

View full text Add to dashboard Cite

Engineering of micro parts is an increasingly important area of industrial activity and this field is rapidly developing further. Thus, the simulation of micro parts also becomes more and more important. As reliable material data is required to obtain accurate simulation results, test setups are also necessary to determine the material properties. An experimental setup for microtensile testing of stainless steel micro specimen (i. e., specimen with at least one dimension below 1 mm) to obtain material data in the temperature range from 20 to 350 °C is presented herein. Heating of the specimen is based on Joule (resistive) heating as it is done in macroscopic testing in Gleeble machines. Contactless measurement of temperatures is conducted by an infrared (IR) camera and the determination of strain by a combination of optical microscopy and digital image correlation (DIC). First samples were made from the stainless steel 17-4PH and the results obtained are presented and discussed in comparison with macroscopic properties of this material.

show abstract

supporting

confidence: 81%

High temperature Gleeble microtensile testing of metallic micro specimens

Kröning

Lang²,

Hofmann

2016

Materials Testing

View full text Add to dashboard Cite

show abstract

“…New sources get activated, most likely in the already present non-coplanar slip bands either by mutual shearing of slip bands as pointed out in Ref. [91], by rare dislocation cross slip events initiating new slip bands [99] or by the activation of already existing sources that require higher activation stress due to smaller segment length L in accord with Orowan's law (s Orowan~1 /L) [100,101]. These new sources again produce expanding dislocation loops on their respective glide planes, which induces the formation of more slip bands leading to a refinement of the slip band substructure (Fig.…”

Section: Discussion Of the Microstructure Evolution: Dynamic Slip Banmentioning

confidence: 84%

Strain hardening by dynamic slip band refinement in a high-Mn lightweight steel

et al. 2016

View full text Add to dashboard Cite

“…[24][25][26] It is known that the mechanical behavior of UFG materials is different than those of CG materials, particularly with respect to the effect of grain size [27] and strain-hardening behavior. [28] Grain-boundary shear, which affects dislocations pile-up, [29] grain-boundary stability of severeplastic deformed materials, [30] dynamic recovery, [31] and dislocation bow-out, [32] have been proposed to describe the mechanical behavior of UFG materials.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Oxide-Dispersion Strengthened Al6063 Alloy with Ultra-Fine Grain Structure

Asgharzadeh

Simchi

Kim

2010

Metall Mater Trans A

View full text Add to dashboard Cite

The microstructure and mechanical properties of the ultra-fine grained (UFG) Al6063 alloy reinforced with nanometric aluminum oxide nanoparticles (25 nm) were investigated and compared with the coarse-grained (CG) Al6063 alloy (~2 lm). The UFG materials were prepared by mechanical alloying (MA) under high-purity Ar and Ar-5 vol pct O 2 atmospheres followed by hot powder extrusion (HPE). The CG alloy was produced by HPE of the gasatomized Al6063 powder without applying MA. Electron backscatter diffraction under scanning electron microscopy together with transmission electron microscopy studies revealed that the microstructure of the milled powders after HPE consisted of ultra-fine grains (>100 nm) surrounded by nanostructured grains (<100 nm), revealing the formation of a bimodal grain structure. The grain size distribution was in the range of 20 to 850 nm with an average of 360 and 300 nm for Ar and Ar-5 pct O 2 atmospheres, respectively. The amount of oxide particles formed by reactive mechanical alloying under the Ar/O 2 atmosphere was~0.8 vol pct, whereas the particles were almost uniformly distributed throughout the aluminum matrix. The UFG materials exhibited significant improvement in the hardness and yield strength with an absence of strain hardening behavior compared with CG material. The fracture surfaces showed a ductile fracture mode for both CG and UFG Al6063, in which the dimple size was related to the grain structure. A mixture of ductile-brittle fracture mode was observed for the UFG alloy containing 0.8 vol pct Al 2 O 3 particles. The tensile behavior was described based on the formation of nonequilibrium grain boundaries with high internal stress and dislocation-based models.

show abstract

The mechanical size effect as a mean-field breakdown phenomenon: Example of microscale single crystal beam bending

Cited by 84 publications

References 54 publications

High temperature Gleeble microtensile testing of metallic micro specimens

High temperature Gleeble microtensile testing of metallic micro specimens

Strain hardening by dynamic slip band refinement in a high-Mn lightweight steel

Microstructure and Mechanical Properties of Oxide-Dispersion Strengthened Al6063 Alloy with Ultra-Fine Grain Structure

Contact Info

Product

Resources

About