The connection of atomic clusters has been investigated using molecular-dynamics simulation to explain the splitting of the second peak of the pair-distribution function in amorphous alloys. It is found that the unevenness of the connecting style of atomic clusters results in the splitting of the second peak and the two subpeaks is caused by a three-atom-shared connection and a one-atom-shared connection between atomic clusters. The underlying reason is that metallic glasses have higher density than liquid alloys and a different connecting style of atomic clusters from crystals.

Generally, bias voltage exercises a great influence on micro-properties (morphology, preferred orientation, mechanical properties, and so on) of the coatings in the process of coating deposited. In order to more systematically explore the influence of bias voltage on microstructure, hardness and adhesion of TiN coatings, TiN coatings were deposited successfully on the surface of 316 stainless steel by high power pulsed magnetron sputtering (HPPMS). A field emission scanning electron microscopy equipped with energy dispersive spectrometer (FESEM/EDS) and an X-ray diffractometer were employed to analyze the surface morphology, chemical composition and phase structure of coatings, respectively. And a nanoindentation and scratch tester was used to investigate the hardness, elastic modulus and adhesion of TiN coatings. Results showed that bias voltage has a great influence on surface morphology of TiN coatings. Moreover, bias voltage can promote preferential orientation and the phase in TiN coating is mainly TiN with a small amount of Ti2N. The influence of bias voltage on the hardness and modulus of TiN coating is not obvious, however, the binding force increases fast first and then decreases slow with the increase of bias voltage. TiN coating has excellent performance when bias voltage is-100V.

TiN coatings were successfully prepared by closed field unbalanced magnetron sputtering (CFUBMS) in this study. The microstructure, composition, phase structure, hardness and adhesion of TiN coating were investigated by SEM, EDS, XRD, and nanoindentation/scratch techniques, respectively. Emphatically, the oxidation behaviors of TiN coating were analyzed and discussed at 550, 600 and 650°C, respectively. Results showed that TiN coatings are golden with loose pyramidal structure, and the phases in TiN coating are mostly TiN and a small amount of Ti. The hardness, elastic modulus and bonding strength of TiN coating are about 23 GPa, 288 GPa and 35 N, respectively. The isothermal oxidation tests in a thermal analyzer at 550°C and 650°C for 19 h suggested that TiN coating has better oxidation resistance at 550°C because it was approximately intact at 550°C. However, the oxidation experiments in a muffle furnace at 600°C and 650°C for only 10 h indicated that TiN coatings were slightly oxidized. Therefore, above 600°C, TiN coating will fail due to the formation of the brittle rutile TiO2 as the oxidation time increases.

This paper studies the melting of Cu-Pd bimetallic clusters with different Pd positions by using molecular dynamics simulation with a general embedded-atom method. The melting of clusters with 55 Pd atomic distributing different positions where the core-layer, second-layer, third-layer, fourth-layer and mixed. It is found that the changing of melting point is strongly related to the position of Pd atomic. The results indicate that the Pd atoms doped in the core layer and surface layer, below the melting point of the second layer and third layer. Meanwhile, this indicate that the Pd atomic doped in the second layer and third layer, the structure of cluster is relatively stable. The irregular phenomena of the melting were induced by the Pd position. This gives a new method to tune the melting point in bimetallic clusters.