Upon deforming a metallic glass at low temperatures, shear tends to localize and this leads to a brittle behavior. However, in the high temperature, and particularly in the supercooled liquid region, homogeneous deformation begins to take place. A bulk amorphous Zr-10Al-5Ti-17.9Cu-14.6Ni alloy was observed to exhibit the Newtonian behavior at low strain rates but becomes n on-Newtonian at high strain rates in the supercooled liquid region. Structures of the amorphous material, both before and after deformation, were examined using X-ray diffraction and high-resolution electron microscopy. Results showed the presence of nanocrystallites in the deformed samples. Thus, the non-Newtonian behavior is attributable to the concurrent crystallization of the amorphous structure during deformation. A mechanistic model is presented to interpret the observed non-Newtonian result. A phenomenological approach is also used to develop the deformation map for bulk metallic glasses in the supercooled liquid region.

High-speed, high-resolution infrared thermography, as a non-contact, full-field, and nondestructive technique, was used to study the temperature variations of a cobalt-based ULTIMET alloy subjected to cyclic fatigue. During each fatigue cycle, the temperature oscillations, which were due to the thermal-elastic-plastic effects, were observed and related to stress—strain analyses. The change of temperature during fatigue was utilized to reveal the accumulation of fatigue damage. A constitutive model was developed for predicting the thermal and mechanical responses of ULTIMET alloy subjected to cyclic deformation. The model was constructed in light of internal-state variables, which were developed to characterize the inelastic strain of the material during cyclic loading. The predicted stress —strain and temperature responses were found to be in good agreement with the experimental results.

Part of the phase boundaries of the solid phases in Ni-Ta system at 1223K, 1173K and 1123K were determined by the diffusion couple and EMPA methods. Based on the experiment data and the information from literatures, the phase equilibrium relationship and thermodynamic properties of the system were analyzed and a complete thermodynamic description were obtained. Apart from the intermetallic phase Ni-8Ta, All the inter-phases were treated with small homogeneity and the sub-lattice model was used to describe them. The calculated results reproduce the experiment information very well.

The enthalpies of formation of the ternary compounds Al₄NiY, Al₂NiY, Al₂Ni₆Y₃, Al₁₆Ni₃Y, AlNiY, Al₃Ni₂Y, AlNi₈Y₃, Al₇Ni₃Y₂, and of the binary compounds Al₂Y containing nickel and Ni₅Y containing aluminum have been determined by high temperature reaction calorimetry. The enthalpy values measured are compared to previously published results where available as well as extended Miedema model predict ions. The melting points of the compounds were determined by DTA and X-ray diffraction was used to confirm the crystal structures of the compounds. The enthalpies of formation of the ternary compounds show a maximum along the 50%Al (mole fraction) section. The ternary compounds appear along lines of constant yttrium content consistent with binary compound solubility extensions.

The isothermal section of the Ni-Pt-Ta ternary system at 1173K was determined by means of the diffusion triple technology and the electron microprobe analysis. The phase relations in this system were studied. Linear compound (Ni, Pt)₃Ta with small solubility forming between Ni₃Ta and Pt₃Ta was identified. Four binary compounds, i.e. Pt₂Ta, Ni₂Ta, NiTa and NiTa₂, and four three-phase fields, i.e. Pt₂Ta +(Ta)+NiTa₂, Pt₂Ta+NiTa₂+NiTa, Pt₂Ta+(Ni, PT)₃Ta+NiTa and (Ni, Pt)₃ Ta+NiTa+Ni₂Ta, were also identified.

The effect of surface damaged layer and Te enrichment layer of Hg_1-xMn_xTe on the indentation size were studied experimentally. Based on the results, the indentation size effect (ISE) of Hg_1−xMn_xTe were discussed using different models, including Meyer’s law, the power-law, Hays-Kendall approach and the theory of strain gradient plasticity. The results show that surface damaged layer weakens ISE of the wafers, but the Te enrichment layer reinforces it. The minimum test load necessary to initiate plastic deformation for different Hg_1−xMn_xTe wafers increases from 3.11 to 4.41 g with the increase of x from 0.05 to 0.11. The extrapolated surface hardness values of Hg_1−xMn_xTe are 347.21, 374.75, 378.28 and 391.51 MPa and the corresponding shear strength values are 694.53, 749.50, 756.56 and 783.12 MPa for Hg_1−xMn_xTe with the x values of 0.05, 0.07, 0.09 and 0.11, respectively.

The 773K isothermal section of the Gd-Ni-Ti system was investigated by X-ray diffractometry, optical microanalysis and electron probe microanalysis techniques. The results show that it consists of 13 single-phase regions, 23 two-phase regions and 11 three-phase regions. The maximum solid solubility of Ti in Ni, Gd₂Ni₁₇, GdNi₅ and Gd₂Ni₇ are 6.0%, 3.0%, 3.0%, and 2.5%(mole fraction), respectively.

High quality Zn-base powder with low oxygen content, fine particle size and fine microstructure can be obtained by gas atomization using nitrogen. Cast and sintered Zn-27%Al alloys (ZMJ) were prepared. Tribological behaviors of the cast and sintered alloys under lubricated and nonlubricated conditions were studied and compared. Worn surfaces and microstructures of these alloys were examined. Results indicate that although the strength of the sintered alloy is considerably less than that of the cast alloy, the sintered alloy has a better wear resistance. The fine microstructure obtained by rap id solidification is beneficial to the wear-resisting property. The wear volume of sintered ZMJ is only 36% and 59% of the wear volume that found in cast ZMJ under non-lubricated and lubricated conditions, respectively. For lubricated wear test, abrasive wear is the major wear mechanism and for non-lubricated wear test, oxidation wear and adhesive wear are the major wear mechanisms.

Influence of heat treatment on mechanical properties and tribological behaviors of Ti and B modified wrought aluminum bronze were studied. The results show that different strength and plasticity combination of the alloy after solution treatment can be obtained by adjusting the ageing temperature. When aged at 450℃, the tensile strength σ_b, yield strength σ_0.2, elongation δ and hardness of the alloy are 1050MPa, 780MPa, 4.5%, HB282, respectively. When aged at 650℃, those of the alloy are 905MPa, 600MPa, 12%, HB232, respectively. Under boundary lubrication condition with pressure above 22.2MPa, alloy with low temperature ageing has the best wear property. However, under the condition involving impact or shock loading, alloy with high temperature ageing is preferable. If the load is not heavy, the alloy under extrusion state is favorable for wear-resisting parts. 

A ZA-27 alloy reinforced with Mn-containing intermetallic compounds was prepared and its tribological behaviors were investigated. By adding Mn, RE, Ti and B into ZA-27 alloy, the test alloy (ZMJ) was fabricated by sand casting. Microstructural analysis shows that considerable amount of Mn-con taining intermetallic compounds such as Al₅MnZn, Al₉(MnZn)₂ and Al₆₅Mn(RE)₆Ti₄Zn₃₆ are formed. Compared to ZA-27, ZMJ shows better wear resistance, lower friction coefficient and lower temperature rise of worn surface under lubricated sliding condition. ZMJ also shows the lowest steady friction coefficient under dry friction condition. The wear resistance improvement of ZMJ is mainly attributed to the high hardness and good dispersion of these Mn-containing intermetallic compounds. It is indicated that the intermetallic compounds play a dominant role in reducing the sever adhesive and abrasive wear of the ZA-27 alloy.

The creep behaviors of the Ni-added Ir₈₅Nb₁₅ alloys were investigated at 1650～1800℃ by compression tests in vacuum. X-ray diffractometry, transmission electron microscopy and scanning electron microscopy we re conducted to characterize the microstructure and lattice misfit change by the addition of Ni in the Ir₈₅Nb₁₅ alloy. The results reveal that the Ni addition has a significant effect on the creep resistance of the Ir₈₅Nb₁₅ two-phase refractory superalloys. Basing on the results, the relationship among the Ni addition, lattice misfit, microstructure development, and the creep behavior in the Ni-added Ir₈₅Nb₁₅ alloys is discussed.

The diffusible hydrogen contents in precharged (Co,Fe)₃V alloy were measured. It is found that atomic ordering can not promote hydrogen penetration in the (Co,Fe)₃V alloy. The ultimate tensile strength (UTS) and ductilities in various condition were also investigated. The results show that the UTS and elongation of disordered alloy are higher than that of ordered one with fixed diffusible hydrogen content and (Co,Fe)₃V alloy with ordered structure is highly susceptible to the embrittlement in hydrogen gas. The factor which may affect the susceptibility to the embrittlement of (Co,Fe)₃V alloy in hydrogen gas is mainly due to that the atomic ordering may accelerate the kinetics of the catalytic reaction for the dissociation of molecular hydrogen into atomic hydrogen. However, it can not be roled out that atomic ordering intensifies planar slip and restricts cross-slip at the grain boundaries and enhances the susceptibility of the alloy to hydrogen embrittlement.

The kinetics of photocatalysis can be us ually described by Langmiur-Hinshelwood adsorption expression. The adsorption can be greatly influenced by the surface properties of photocatalyst. Triple layer model (TLM) was c hosen to describe the surface adsorption of TiO₂ based on electrical double la ye r (EDL) theory at the TiO₂/water interface. And through the potentiometric titration the parameters of TLM were determined by the extrapolation method and Fiteql3.1 software. The results show that surface complexation dominates the surface charge and the numerical calculation fits the experiment data satisfactorily.

Protective coatings are essential for superalloys to serve as blades of gas turbines at high temperatures, and they primarily include aluminide coating, MCrAlY overlay coating, thermal barrier coating and microcrystalline coating. In this paper, all these high-temperature coatings are reviewed as well as their preparing techniques. Based on the most application and the main failure way, the importance is then presented for further deepgoing study on the high-temperature oxidation law of aluminide coatings.