篢he thickening of bainite and equilibrium phase in a Cu-Zn alloy was in situ observed by means of TEM at heating stage. The thickening kinetics of both bainite and equilibrium phase is inconsistent with diffusional ledge mechanism. There is an obvious shear feature during bainite thickening.

篢he phase transformations in the Fe-28AI alloys with or without addition of Cr were studied by means of electron microscopy and X-ray diffraction techniques. The B2 antiphase domains (APD) has already been formed during quenching process from 1080℃.The Fe-enriched a-phase may precipitate along the grain boundaries in the alloys when cooling slowly through temperature range of just B2-phase occurred. In the Fe-28A1-5Cr alloy. the fine CrN-phase may also precipitate. The B2→D03 transformation was found to be a slow process in the sheet specimens.

篢he in situ TEM observations of dislocation emission, motion and the initiation of nanocrack in brass in corrosive solution were carried out. Using a special constant displacement device, the dislocation configuration change ahead of a loaded crack tip before and after anodic dissolution in the deionized water and the initiation, propagation of nanometre scale stress corrosion cracks has been observed. The results showed that SCC in brass thin foil specimen could occur in water. The localized anodic dissolution of brass in water at room temperature facilitated dislocation emission, multiplication and motion. A nanocrack initiated in the DFZ or at the blunted crack tip in corrosion solution after dislocations emission, multiplication and motion reached a critical condition. Because of the influence of the corrosion solution, the nanocrack will propagate and form a cleavage or intergranular microcrack during stress corrosion instead of blunting in to a void as it does during a tension test without solution.

篒n situ recrystallization (ISR) during elevated temperature deformation was found in a Fe3AI based alloy by TEM observation and metallographic examination. Good elevated temperature ductility of the Fe3Al alloy is closely related to ISR. Through olimb or cross slip, the dislocations created in deformation process change into a dislocation array, which attracts lattice dislocations and increases the misorientation between crystals at the both sides of itself during further deformation, and gradually evolves into a subboundary and even a high-angle boundary.

篈n Experimental investigation was carried out of the properties of quenched and tempered steel 42CrMo subjected to proportional cyclic loadings and biaxially nonproportional circular strain paths. The corresponding angles,θ1 between plastic strain rate and deviatoric stress and θ2 between plastic strain rate and deviatoric stress rate, and the plastic modulus fluctuate periodically in a cycle, and their fluctuating amplitudes decrease significantly with increasing equivalent strain amplitude under circular strain paths. At the same equivalent strain amplitude, the average plastic modulus under circular strain path is more than the modulus under torsional cycling, and the difference of them is larger with the smaller equivalent strain amplitude. At small equivalent strain amplitude , the equivalence between the response of equivalent shear strain and the one of axial strain is very poor.

篖iquid structure features of hypereutectic Al-18%Si alloy have been analyzed by DSC analysis and rapid solidification method. The influences of superheating temperature and P on them have also been studied. Three zones of molten hypereutectic Al-18%Si alloy stracture: a micro-inhomogeneous zone in low liquid temperatures,a transition zone from the micro-inhomogeneous to the micro- homogeneous in middle temperature and micro-homogeneous zone in high temperature are presented. Under low temperature,the micro-inhomogeneity was strengthened by the addition of P atoms.

篢he room temperature fatigue crack growth rates fo the Ti3Al-Nb-Mo-Valloys with different microstructures by 3 regimes of heat treatment have been determined. The volume fraction of primary α2-phase,grain sizes of matrix, morphology of β-transformation products and static yield strength are the major factors influential in both the fatigue threshold and fatigue crack growth rate of the alloy. The effect of stress ratio on da / dN is consistent with that on the conventional materials. According to observations of SEM fractographs together with the fatigue crack growth rate measurements, a brief discussion on the fatigue crack propagation behaviour was made.