The possibility of the substitution of Co as binder in the cemented carbide with dispersionprestrengthened Ni powder has been investigated. The quality of the WCNi cemented carbide can be improved with predispersion of nanosized Al2O3 powder into Ni. The mechanical properties of WC8%Ni(Al2O3) alloy, prepared by this method is comparable with WC8% Co cemented carbide.

Effect of RE on the properties and the microstructure of CuNiZn alloy has been studied by SEM, metallographic microscope and XRay. Results show that the RE has effect both on the mechanical properties and the microstructure of the alloy. The casting structure and recrystallization structure has become fine, the fensile strength and hardness have been increased and the elongation has been decreased; but with RE addition of over 1.0%, the hot plastisity of the alloy has become bad, thus the alloy is difficult to form.

Microstructure and dislocation behavior of the aluminium magnesium alloy containing scandium in the process of superplastic deformation were investigated by transmission electron microscope.The results show that four processes will take place in sequence during superplastic deformation, i.e., dynamic recrystallization;dislocations come from grain boundaries;motion of the dislocations within the grains is prohibited by the secondary phase Al3Sc as well as dislocations climb up and go over the dispersed particles;dislocations are annihilated in grain boundaries.It is found that dynamic recrystallization is the microstructure effect of the alloy and play a role in inducing microfine grain superplasticity during superplastic deformation. The dominant mechanism of superplastic deformation is that grain boundary sliding process will be accompanied by intergrainular dislocations.

The effect of the total amount of Ni and Cu on the properties of the liquid phase sintered MoWNiCu alloy was investigated. The results show that, under the condition of a given ratio of Ni to Cu, the sintering temperature decreases with the increase in the total amount of Ni and Cu, the ultimate tensile strength b increases rapidly to the maximum value 1100 MPa , and then decreases slowly. When the amount is less than 6%wt, the hardness of the sintered alloy holds maximum value HB370, but when the amount is larger than 6%wt, the hardness decreases. The larger the amount of Ni and Cu, the finer the grain of the alloy.

The TbDyFeMn system alloys are prepared by arc melting in an inert atmosphere water cooled copper hearth and by float zone melting (ZM) technique. By measuring the ascast rod sample's magnetostriction and analyzing its microstructures with EPMA and Laue Xray techniques, it is found that the content of element Mn affects both the material's magnetostriction properties and the microstructure. The optimum content of element Mn in this material for maximum magnetostriction is given. It offers the convincing foundation for the development of the giant magnetostriction materials.

The mining cemented carbide was regenerated by lowpressure HIP. The results show the increase in the fransverse rupture strength and the decrease in the porosity(to A00). The service life of the regenerated cemented carbide is similar to that of conventional cemented carbide. The mechanism of the denisfication of lowpressure HIP is analysed.

Z]The microstructure of steel bonded carbide GJW35 after heat treatment has been analysed, and influence of the microstructure on the nucleation and propagation of thermal fatigue cracks of this alloy has been studied. The results show that the thermal fatigue cracks nucleate and propagate preferentially in the hard phase, and the nucleation and propagation are stoped by the steel based phase. By improving microstructure, the thermal fatigue resistance of this alloy can be raised.

Z]Mechanical alloying process of MoSi2 has been studied by XRay, SEM, TEM. It shows that the process may be divided into four stage stages:(1) initial stage of activation;(2)activating;(3)alloying;(4)becoming microcrystal and amorphous solid.

The effects of breakdown rolling temperature for molybdenum plate billet on the properties and microstructure of final product have been investigated. The results show that the grains obtained by low temperature breakdown rolling are much slimmer than that by high temperature one, and the boundaries by former process have much higher degree of chain over lapping. Both of the factors provide the final product by low temperature breakdown proccess with higher strength and elongation, thus better comprehensive properties as a whole.

A special WC electrode is developed from the crude crystalline WC powder (obtained by hightemp reduction and carburization) with the addition of modified lowH2 flux to form coating. The said electrode features better welding performance than other buildup welding rod, A.C/D.C services, high hardness and good wearability, and has bright prospect of application.