Alloy

About: Alloy is a research topic. Over the lifetime, 171884 publications have been published within this topic receiving 1719420 citations. The topic is also known as: alloys.

Mechanical rolling formation of interpenetrated lithium metal/lithium tin alloy foil for ultrahigh-rate battery anode.

Abstract: To achieve good rate capability of lithium metal anodes for high-energy-density batteries, one fundamental challenge is the slow lithium diffusion at the interface. Here we report an interpenetrated, three-dimensional lithium metal/lithium tin alloy nanocomposite foil realized by a simple calendering and folding process of lithium and tin foils, and spontaneous alloying reactions. The strong affinity between the metallic lithium and lithium tin alloy as mixed electronic and ionic conducting networks, and their abundant interfaces enable ultrafast charger diffusion across the entire electrode. We demonstrate that a lithium/lithium tin alloy foil electrode sustains stable lithium stripping/plating under 30 mA cm−2 and 5 mAh cm−2 with a very low overpotential of 20 mV for 200 cycles in a commercial carbonate electrolyte. Cycled under 6 C (6.6 mA cm−2), a 1.0 mAh cm−2 LiNi0.6Co0.2Mn0.2O2 electrode maintains a substantial 74% of its capacity by pairing with such anode. Sluggish lithium diffusion on the surface of Li metal anodes poses a fundamental challenge. Here the authors report a Li/Li22Sn5 alloy design to address this issue. The composite anode sustains stable Li stripping/plating cycling with a low overpotential of 20 mV under 30 mA cm−2 in a commercial carbonate electrolyte.

Effects of yttrium on microstructure and mechanical properties of hot-extruded Mg–Zn–Y–Zr alloys

Abstract: This article studied the effects of yttrium on microstructure and mechanical properties of extruded Mg–Zn–Y–Zr alloys. Three kinds of Mg–5.5Zn– x Y–0.4Zr alloys with variable yttrium content were hot-extruded at different temperature to investigate the microstructure evolution and dynamic recrystallization (DRX) process of these alloys. The alloys with low yttrium content as 0.74 or 1.35 wt.% consist of α-Mg and large I-phase particles, while the alloy with high yttrium content as 1.72% consists of α-Mg, I-phase and W-phase. For the alloys with low yttrium content as 0.74 or 1.35 wt.%, fine I-phase precipitates formed during the hot extrusion process. These fine precipitates and particles, which are from destroyed I-phase pockets, provide obvious strengthening effects on the alloys. For the alloy with high yttrium content as 1.72%, fine I-phase precipitates did not form during the hot extrusion process. Further, coarse W-phase pockets were difficult to be destroyed in the alloy extruded at moderate temperature. As a result, the yield strength of this alloy is moderate compared to that of the alloy with yttrium content of 1.35%, especially when extruded at low temperature. Furthermore, it was observed that the growth of DRX grains was suppressed due to the pining effect of particles or precipitates during the hot extrusion process in all the alloys studied.