Metals

543 KiB

Open AccessArticle

Deformation of Honeycomb with Finite Boundary Subjected to Uniaxial Compression

by Dai-Heng Chen and Kuniharu Ushijima

Metals 2013, 3(4), 343-360; https://doi.org/10.3390/met3040343 - 25 Nov 2013

Cited by 5 | Viewed by 6182

In this paper, the crushing behavior of hexagonal honeycomb structures with finite boundaries (finite width and height) subjected to in-plane uniaxial compressive loading is studied based on the nonlinear finite element analysis. It is found that stress-strain responses for the honeycombs with finite boundaries can be classified into two types: Type I and Type II. Such a characteristic is affected by the wall thickness, the work-hardening coefficient and the yield stress for the honeycombs. Furthermore, a transition from the symmetric to asymmetric deformation mode can be observed in Type I, and these deformed cells were localized in a horizontal layer. However, for the case of Type II response, the symmetric and asymmetric deformation modes can be observed simultaneously, and the region of the asymmetric mode was formed by the cell layer along the diagonal direction. As a result, the shear deformation behavior was developed along that direction. Moreover, the effect of work-hardening on the deformation behavior for the honeycombs with finite boundaries can be explained from that for infinite honeycombs. Full article

(This article belongs to the Special Issue Metal Foams 2013)

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180 KiB

Open AccessArticle

The Effect of Increasing Sn Content on High-Temperature Mechanical Deformation of an Mg-3%Cu-1%Ca Alloy

by Georgios S.E. Antipas

Metals 2013, 3(4), 337-342; https://doi.org/10.3390/met3040337 - 1 Nov 2013

Cited by 2 | Viewed by 4850

Abstract

Chill casting of magnesium alloy samples with secondary alloying elements of Cu, Ca and Sn at % w.t. concentrations in the range 1–5, 0.1–5 and 0.1–3 respectively, gave rise to appreciably enhanced resistance to high-temperature creep, while maintaining good heat conductivity. The latter was considered to be driven by Cu and Mg-Cu intermetallics while it was clear that Sn mediated the high-temperature performance, mainly via networks of Mg₂Sn and MgCaSn precipitates along the Mg matrix grain boundaries. It was postulated that Sn formed intermetallics by preferential substitution of Ca atoms and, thus, did not degrade the heat conductivity by retaining Cu. The % w.t. stoichiometry with the optimum combination of heat conductivity and resistance to high-temperature creep was found to be Mg-3Cu-1Ca-0.1Sn. Full article

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5589 KiB

Open AccessArticle

Twinning Phenomena along and beyond the Bain Path

by Sandra Kauffmann-Weiss, Alexander Kauffmann, Robert Niemann, Jens Freudenberger, Ludwig Schultz and Sebastian Fähler

Metals 2013, 3(4), 319-336; https://doi.org/10.3390/met3040319 - 9 Oct 2013

Cited by 13 | Viewed by 10738

Abstract

Twinning is a phenomenon that occurs, e.g., during deformation, martensitic transformation and film growth. The present study shows that the crystallography of twinning can be described by two twinning modes along the complete Bain transformation path and beyond connecting body-centered and face-centered cubic structures. To probe this concept, we used strained epitaxial films of the Fe-Pd magnetic shape memory system. As the substrate acts as an absolute reference frame, we could show by pole figure measurements that all observed twinning can be a body-centered and face-centered cubic twinning mode. This continuously transforms towards identity when approaching the complementary structure. Full article

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Metals, Volume 3, Issue 4 (December 2013) – 3 articles , Pages 319-360

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