Fatigue tests under nominal I and mixed modeⅠ/ Ⅱ loading were carried out on Ni3Al alloy single crystals. The effects of crystal orientation and load mode on the fatigue cracking behavior were studied. It was found that the crack paths are dependent on both crystal orientation and applied load mode. Fatigue cracking in single crystals under mixed mode Ⅰ/ Ⅱ loading always occurs on the planes with maximum resolved shear stress rather than on those with maximum normal stress. The cracking behavior predicted by main mixed mode criteria in polycrystalline materials under a mixed mode can be explained from the present results.

The [112]aluminum single crystal was tested in full push-pull at room temperature in air, with specific stress amplitudes and frequence of 15 Hz. Detailed observations were made on side-surface which contained Burgers vectors of two primary slip systems and front-surface. On front-surface typical PSBs topographies and crack initiation along PSBs have been seen. However, on side-surface where PSBs were invisible, a more complicated deformation appearance was developed, and microcracks initiated along extrusions or intrusions which were formed without a definite crystallographic relation to PSBs' The results show again that, without the aid of the surface roughness of PSBs, cracks can still be nucleated, and that the accumulative structural damage in single crystal aluminum is believed to be one of basic factors controlling crack initiation. Yet it was shown that the deformation and damage processes in single crystal aluminum are orientation dependent, and that the marked cross-slip in poly-slip crystals could accelerate the damage process which can be manifested best on side-surface.

The effect of strain rate is studied on the tensile yield strength and elongation of γtitanium aluminide with a near lamellar microstructure. It is found that γ titanium aluminide manifests brittle-to-ductile transition (BDT) at elevated temperature and the brit-tle-to-ductile transition temperature (TBDT) is positively sensitive to the strain rate. The activation energy of BDT has been determined to be 324 kJ / mol, which is approximately the same as the self-diffusion activation energy of atoms in the Tial alloy. From the approximation, and the additional fractography analysis and theoretical calculation, it is concluded that the course of γtitanium aluminide is controlled by dislocation climbing.

The oxidation behavior of Ti-50al, Ti-45al-10Cr and Ti-50al- 10Cr (atomic fraction, %) alloys at 800-1100℃ was investigated. at 800 and 900℃, Ti-45al-10Cr alloy formed a similar layered scale with Tial, consisting of an outer layer of TiO2, an intermediate al2O3 barrier and an inner layer of a mixture of al2O3 and TiO2, exhibited larger weight gains than Ti-50al due to the dopping effect of Cr. at 1000 and 1100℃, however,Ti-45al-10Cr alloy formed a continuous al2O3 enriched scale, which had much smaller weight gains than Tial alloy. Moreover, Ti-50al- 10Cr alloy exhibited an excellent oxidation resistance at 80O-1100℃ due to the formation of a protective al2O3 scale.

Corrosion resistance of the cast superalloy K38G and its sputtered nanocrystalline coating was investigated in CO in the temperature range 850-1000℃. The methods included thermogravimetric measurements, X-ray diffraction, and SEM with EDaX.The results indicated that the cast K38G alloy formed Cr2O3 and TiO2 scales, which followed parabolic rate law at any temperature in CO. The sputtered K38G nanocrystalline coating, however, formed al2O3 scale as a result of the enhancement of the selective oxidation of aluminium by nanocrystallization. The weight gain of the nanocrystalline coating is about 3-5 times Smaller than that of the cast alloy. Therefore nanocrystallization significantly improves the corrosion resistance of K38G superalloy.

The corrosion characteristics of as-cast SiCp/ 2024 al composites in chloride (Cl-) media were investigated using scanning micro reference electrode technique,electrochemical analysis and scanning electron microscopy. The composites have less resistant to pit initiation than the corresponding aluminum alloy. The increase in volume fraction of SiCp reinforced phase resulted in a signiflcant decrease of pitting potential. In situ mapping of the active centers in composites revealed that local breakdown of passivity and micropitting corrosion could happen even at the open-circuit potentials, and the increase of volume fraction of SiC particles reinforced phase in the composites led t0 a significant increase of active centers on their surfaces. Pitting corrosion attack occured preferentially at the interfaces of SiC / al, and al2Cu or (Cu, Fe, Mn)al6 inclusions / al for the composites.

Effect of hydrogen content on the mechanical properties, stress-corrosion cracking life (SCCL), deformation mechanism and fracture mode in the 2091-T6 al-Li alloy sheet has been studied systematically. The experimental results show that as the H content in the alloy is lowered from 0.92μg / g to 0.08μg / g, the mechanical properties of σb,σ0.2 and δ,and SCCL are increased significantly. The deformation mechanism is also changed from the mode of dislocation shearing δ' phase to the Orowan looping mode, and the fracture appearance of tensile and stress-corrosion specimens is changed from typical intergranular brittle fracture to transgranular ductile fracture, the characteristic of low toughness fracture induced by hydrogen embrittlement disappeared completely The mechanism of the effect of dehydrogenation on the deformation and fracture mode in al-Li alloy is also discussed, and the concept of "Extra Low Hydrogen al-Li alloy" is proDosed in the present paper.

The microstructure, phase transformation and mechanical property in al-based nanocrystalline alloys containing dispersive particles were studied in detail. It is shown that the sizes of α-al grain and dispersive particles decrease and α-al13(Fe,V)3Si particles in al-Fe-V-Si microcrystalline alloys are substituted by al8Fe4Mm or al20Fe5Mm phase with the increase of Mm content. The transition of metastable al8Fe4Mm to stableα-al13(Fe,V)3Si phase takes place near 673 K. In addition, 1.0%Mm nanocrystalline alloy exhibits 2 times higher strengthes in tensile fracture and fatigue fracture than al-Fe-V-Si microcrystalline alloy, and has more better thermal stability.

The morphologies and structures of iron compounds in an al-Si alloy have remarkable heredity. a technique has been presented for eliminating the heredity of needle-form iron compounds and planting nuclei for new iron compounds and spheroidizing them, and then the harmful effect of needle-form iron compounds in al-Si alloy on the mechanical property can be eliminated. The spheroidisation mechanism of iron compounds has also been investigated.

The corrosive wear behavior of Cr-Mn-N casting stainless steel with addition of Cu and Mo in media of H2SO4, HNO3, HaC acid is investigated. Its corrosive wear resistance is much better than that of 304 stainless steel. and the reason is that, besides the similar corrosive resistance between Cr-Mn-N casting stainless steel and 304 stainless steel, the former has a better work-hardening ability than that of Ni series stainless steel in wear experiment. So it is fit for dominative wear condition.

The influence of the stability of eutectic carbide in high Cr-Ni cast iron on abrasive wear resistance has been investigated on a high temperature abrasive wear tester, in which atmosphere can be controlled. The obtained results show that the carbide can not act as a resistant to wear if its chemical stability at elevated temperature is too bad, and the wear resistance of the alloy is decreased rapidly.

Based on the relationship between the Wilson parameters and temperature,the Wilson equation can be extended to estimating activities of components of binary and multicomponent liquid alloys at given temperatures only by using the activities of components of binary liquid alloys measured at some temperatures. The results show that the estimation values of activity of multicomponent liquid alloys are in good agreement with their experimental data of activity.

a high order sub-regular solution modeI for predicting the component activities in a homogeneous region of a quaternary system was developed in the Shanghai Enhanced Lab of Ferrometallurgy, which is designated as SELF-SReM4. It is composed of some polynomials of excess mole free energies versus content variable. a group of parameters is included in the polynomials. along with the reliable known thermodynamic properties associating the homogeneous region the parameters can be evaluated. and then the component activities in that region are possible to be predicated. This paper is devoted to illustrate the applications of SELF-SReM4 for molten slag of MnO-SiO2-al2O3-CaO and its sub-ternary systems. The evaluated results were very close to those of slag-metal equilibrium experiments and the Chipman's and Pelton's results.

By using computer-aided techniques of equilibrium calculations for multicomponent and multiphase systems, a computer model has been developed to simulate distribution behavior of Ni, Co, Sn, Pb, Zn, as, Sb,Bi, au and ag in copper smelting. The predicted results by the present computer model are compared with the known commerical data from Gui Xi Smelter in China and Horne Smelter in Canada. The agreements between the computer prediction and the commercial data are excellent, so that the present computer model can be used to monitor and optimize the actual industrial operations of copper smelting and control the distribution behavior of accessory elements in copper smelting.

The mass transport coefficient of phosphorus in C-saturated molten iron at 1350℃ had been determined during the dephosphorization of dicalcium ferrite by mechanical stir method. The results are shown as follows: the mass transport process of phosphorus in molten iron was promoted by using mechanical stir, and the mass transpori coefficient of phosphorus, kmρm, was equal to 4.60×10-2g / (cm2. s).

Partial phase equilibrium relationships and compositions in the Ti-al binary system are studied by diffusion couple and EPMa method. Interdiffusion coefflcients of β,αand γare calculated by Matano method. The results showed that the partial phase equilibrium relationships should be β/ αand α/ γ,and the interdiffusion coefficient of γ phase has a minimum value at stoichimetric composition.

Ultrafine particles and powders of metallic α-Co were prepared in an aqueous solution of Co2+ by γ-ray radiation. The ultrafines appear as nanocrystallined particles according to X-ray and electron diffraction. The average size of particles is 30 nm while concentration of cobalt acetate solution, irradiation dose and solution pH are in the range of 0.005-0.2 mol / L, 2.3×104-3.9 ×105 Gy and 6.0-10.0 respectively.

In this paper, the solution of problems occured during UBET backward simulation of a blade is studied. at the same time, a series of calculation methods is put forward and the UBET backward simulation system is compiled which is used to analyze and define the shape of the blank of the blade.