Metallic materials under extreme thermo-mechanical-environmental service conditions oftentimes rely on the formation of dense and protective oxide layers, e.g., typically alumina or chromia. Their failures, however, usually emerge from morphological instability such layers at oxide-alloy interface. This work suggests that a tensile, biaxial stress arises in substrate alloy due to concomitant ox...

We present first-principles studies of the adsorption of Sb and Ag on clean and Sb-covered Ag (111). For Sb, the substitutional adsorption site is found to be greatly favored with respect to on-surface fcc sites and to subsurface sites, so that a segregating surface alloy layer is formed. Adsorbed silver adatoms are more strongly bound on clean Ag(111) than on Sb-covered Ag. We propose that the...

Resonant x-ray reflectivity of the surface of the liquid phase of the Bi(43)Sn(57) eutectic alloy reveals atomic-scale demixing extending over three near-surface atomic layers. Because of the absence of an underlying atomic lattice which typically defines adsorption in crystalline alloys, studies of adsorption in liquid alloys provide unique insight on interatomic interactions at the surface. T...

We have formed compositionally abrupt interfaces in silicon-germanium (Si-Ge) and Si-SiGe heterostructure nanowires by using solid aluminum-gold alloy catalyst particles rather than the conventional liquid semiconductor-metal eutectic droplets. We demonstrated single interfaces that are defect-free and close to atomically abrupt, as well as quantum dots (i.e., Ge layers tens of atomic planes th...

Abstract. Applied at elevated temperature compared with in situ-whisker reinforced titanium matrix composite(TMC) higher than alloy 50~150℃. The advantage of TMC Ti-Al intermetallic compound is lower cost, better weldable property, simple fabrication process; density super alloy. One important demand sheet for high application used speed craft lighter part fabricated by SPF/DB technology. This ...

An immiscible alloy with an amorphous phase, Al–Co–La–Bi, was designed by the combination of empirical parameters mixing entropy, predicted ground state diagram constructed Materials Project for database ab initio calculations, and thermodynamic calculations using FactSage software FTlite database. The solidification microstructure rapidly solidified melt-spun ribbons Al–Co–La–Bi investigated f...

To the Editor: A recent article in PNAS by Asikainen and Werle (1) reports on the occurrence and morphology of ferromanganese nodules found in a New Hampshire lake. The authors offer data on the shapes, banding, composition, and distribution of the nodules and crusts. They also state that my paper (2) claims that the morphology of such nodules is controlled by elemental concentrations and that ...

This paper presents an investigation on the microstructure and property of 4043 Al-alloy parts built using a novel layer-deposition technique based on a variable polarity gas tungsten arc welding (VP-GTAW) process. Processing parameters strongly affect the geometry, microstructures, roughness, and hardness of a deposited part. A hollow cylindrical part with 120 layers is built up with a good su...