TiN/AlN nanoscale multilayer films were deposited on silicon by pulsed laser depositions, with nominal periods of 10, 20, 40 and 100 nm and total thickness of the TiN/AlN multilayer of y500 nm. The microstructure, composition and period of samples were characterised by SEM, nanoindentation and friction tests. The SEM result indicates that the microstructure of the TiN/AlN multilayer film has a good period. The nanoindentation test shows that the hardness of the TiN/AlN multilayer films range from 22 to 30?6 GPa, which is higher than that of a single TiN film (17 GPa). The TiN/AlN multilayer film with a maximum hardness value of 30?6 GPa is associated with more effective combination of solid solution hardening (TiAlN) on the interface. This point is confirmed by X-ray photoelectron spectroscopy. The influences of the period on the microstructure and mechanical properties of films are also investigated. The X-ray diffraction patterns indicate that TiN film exhibits nanocrystalline columns, whereas AlN shows a crystallite structure. The TiN/AlN multilayer film presents typical microstructural features for both materials. In tribological tests, a ball on disc test is used to determine the friction coefficients. The coefficient of steady state friction against a Si 3 N 4 ball varies considerably between films grown by different periods. The lowest friction coefficient of m50?33 is shown at the TiN/AlN multilayer film, whereas the TiN and AlN single layer film ranges from 0?33 to 0?82.

Strain rate change tests were performed under uniaxial tension-compress cycle loading during low cycle fatigue of AZ91D magnesium alloy using plastic strain as the control variable. Results show that the cyclic softening phenomenon is appeared in testing materials when cycle strain amplitude is less than 0.4%. With the increase of the cyclic strain amplitude, material displays obviously cyclic hardening; at the same time, the additional strengthening degree of materials is increased. Further study found that the slope of the curve is unchanged when the strain amplitude is more than 1.0%. The changes of strain rate has a little impact on the low cycle fatigue life of AZ91D magnesium alloy, conversely, the changes of strain amplitude has a great influence on low cycle fatigue life on the material. With the improvement of strain amplitude, fatigue life is reduced obviously. In addition, the Coffin-Manson formula fitting equation has good consistency with the experimental data, which is used in low cycle fatigue prediction life.

Al2O3 and Al2O3-40wt.%TiO2 ceramic coatings on H13 hot-worked die steel have been prepared by plasma spraying, and then the microstructure, micro-hardness as well as wear resistance of the prepared coatings have been investigated by means of x-ray diffraction (XRD), scanning electron microscope (SEM), Vickers hardness tester and ball-on-disk high temperature tribometer. The results showed that the plasma sprayed ceramic coatings are of higher hardness and wear resistance than H13 hot-worked die steel.

TiN/AlN nanoscale multilayer films were deposited by pulsed laser ablation on silicon, with different argon and nitrogen gas flow rates. The total thickness of the TiN/AlN multilayer film was approximately 1μm. The friction and corrosion properties were studied by tribological and corrosive tests. In tribological tests, ball-on-disc was used to determine coefficients of friction and wear rates. The coefficient of friction against a Si3N4 ball varied considerably between films, as does the wear rate. The lowest coefficient of friction μ=0.97 was shown at sample 1, whereas the other three multilayer films were ranged from 1.0 to 1.5. In corrosion test, the anodic polarization characteristics were measured in a 3.5% NaCl solution at room temperature to examine the corrosion resistance. The potentiodynamic polarization measurements showed that for all the multilayer films the corrosion potential shift to higher values, and the corrosion current density decreased with increasing of nitrogen gas flow rate, which indicate a higher nitrogen partial pressures lead to a better corrosion resistance.