The effect of superposed transitions in actuators with layered shape memory alloy (SMA) films undergoing martensitic phase transformation is analyzed in terms of a model developed for two layers of different composition, deposited at the same temperature on a substrate. A significant difference is observed in the actuation versus temperature relationship, depending on the thermal and elastic pr...

Friction Surfacing Cladding (FSC) is a relatively new solid state process to deposit thin metallic clad layers on substrates. It employs a hollow rotating tool that supplies the clad material. Frictional and viscous heating take place that soften the clad material and enhance the bonding of the clad material to the substrate. Thin layers of commercially pure aluminium can be deposited well on a...

A Si-based waveguide photodetector with a response in the 1.3–1.55m wavelength range is demonstrated. The active absorption layer of the pin photodiode consists of a SiGeC alloy epitaxially grown on a Si substrate with a Ge content of 55% and a thickness of 800 Å. The external quantum efficiency for a 400m-long waveguide, measured by using a single-mode fiber coupled to the waveguide facet, is ...

From systematic ab initio calculations for the alloy system Mg12xAlxB2, we find a strong tendency for the formation of a superstructure characterized by Al-rich layers. We also present a simple model, based on calculated energies and an estimate of the configurational entropy, which suggests that the alloy has two separate concentration regimes of phase separation, with critical points near x50...

A new superelastic Ti-23Hf-3Mo-4Sn biomedical alloy displaying a particularly large recovery strain was synthesized and characterized in this study. Its native passive film is very thick (18 nm) and contains very protective TiO2, Ti2O3, HfO2, MoO2, and SnO2 oxides (XPS analysis). This alloy revealed nobler electrochemical behavior, more favorable values of the corrosion parameters and open circ...

The mobility of two-dimensional electron systems in strained Sit-,Ge, quantum wells was studied at low temperatures as a function of the germanium content in the well. While mobilities exceeding 30 000 cm*/V s have been achieved for pure Si layers, they dropped to less than 3000 cm2/V s for Sie8sGect2 wells, demonstrating the etlect of strong alloy disorder scattering. This was confirmed by the...

The structure of a titanium nitride film coated by arc ion plating on a Ni-50Ti shape memory alloy was characterized by X-ray photoelectron spectroscopy (XPS). The corrosion behavior of the titanium nitride-coated Ni-50Ti alloy was examined in 0.9% NaCl solution by potentiodynamic polarization measurements and a polarization resistance method. XPS spectra showed that the titanium nitride film c...

Vertically aligned InAs nanowires (NWs) doped with Si were grown self-assisted by molecular beam epitaxy on GaAs[111]B substrates covered with a thin SiO x layer. Using out-of-plane X-ray diffraction, the influence of Si supply on the growth process and nanostructure formation was studied. It was found that the number of parasitic crystallites grown between the NWs increases with increasing Si ...

Friction stir processing (FSP) was used for the fabrication of Al-B4C surface composite. Al-Mg-Si alloy was considered as the substrate and B4C particles were incorporated into the substrate by thermo-mechanical effect of FSP. The effect of tool dimensions and different rotational speeds on the microstructure and microhardness of the composite layers was evaluated and the optimum process parame...