Yukiko Ogawa

A lightweight shape-memory magnesium alloy

Lightweight shapeshifting alloys Shape memory alloys (SMAs) spring back into shape after they are deformed, a useful property for a variety of applications. Transition metal alloys, which are robust but dense, dominate the SMA landscape. Ogawa et al. report a new type of lightweight SMA made from magnesium and scandium, which has comparable properties to known SMAs but at significantly lower density. Although this magnesium-scandium alloy is limited to low-temperature applications, development of a new lightweight class of SMAs could be on the horizon. Science, this issue p. 368 A lightweight magnesium-scandium alloy has shape-memory properties, comparable to traditional shape-memory alloys. Shape-memory alloys (SMAs), which display shape recovery upon heating, as well as superelasticity, offer many technological advantages in various applications. Those distinctive behaviors have been observed in many polycrystalline alloy systems such as nickel titantium (TiNi)–, copper-, iron-, nickel-, cobalt-, and Ti-based alloys but not in lightweight alloys such as magnesium (Mg) and aluminum alloys. Here we present a Mg SMA showing superelasticity of 4.4% at –150°C and shape recovery upon heating. The shape-memory properties are caused by reversible martensitic transformation. This Mg alloy includes lightweight scandium, and its density is about 2 grams per cubic centimeter, which is one-third less than that of practical TiNi SMAs. This finding raises the potential for development and application of lightweight SMAs across a number of industries.

Correction: Hasan, I., et al. A Galactose-Binding Lectin Isolated from Aplysia kurodai (Sea Hare) Eggs Inhibits Streptolysin-Induced Hemolysis. Molecules 2014, 19, 13990-14003

Laboratories of Glycobiology & Marine Biochemistry and Molecular Toxicology, Department of Lifeand Environmental System Science, Graduate School of NanoBio Sciences, Yokohama City University,22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan; hasanimtiaj@yahoo.co.uk (I.H.);rajia_bio@yahoo.com (S.R.); yasukoide04@yahoo.co.jp (Y.K.); kanaly@yokohama-cu.ac.jp (R.A.K.)

Age-Hardening of Dual Phase Mg-Sc Alloy at 573 K

In this study, we investigated the effect of aging treatment at 573 K on hardness in Mg-Sc alloy with bcc/hcp dual phase prepared by annealing at 873 K. It was found that hardness abruptly increased after some incubation time, and then reached steady state level. Moreover, by further aging, the hardness increased again. It was confirmed by SEM observation and XRD that the initial drastic hardening was due to the precipitation of α phase. Furthermore, XRD results suggested that the secondary hardening was attributed to the formation of MgSc phase with ordered B2 structure.

Resistive Switching Behavior in Undoped α-Fe2O3 Film with a Low Resistivity

The resistive switching behavior of a low resistive p-type α-Fe2O3 thin film sandwiched between Fe bottom electrode and top electrodes of various materials (Fe, Ni and TiN) was studied by current-voltage measurements. When TiN was used for top electrode of memory cell, the reversible resistive switching behavior was observed for over 100 cycles. From impedance measurement, it was suggested that the resistive switching behavior in the TiN/p-type α-Fe2O3/Fe device is attributed to the change of the contact resistance in the interface between TiN and α-Fe2O3 layers.