从材料的综合流动曲线及聚合物、粘结剂的流动性能，分析了金属注射成形喂料的流动行为，给出了用毛细管粘度计测量金属注射成形喂料粘度并确定其流动曲线参数的分析方法。

The evolution of the microstructure and the dimension of as-molded parts were studied on the basis of the thermogravimetric analysis of wax-based MIM binder. The results show that the binder removal speeds are different in different temperature ranges during binder removal process. The evolution of the microstructure of as-molded parts during binder removal process clearly showed the initiation and formation of connected pore structure , which is the removal chan-nel of the binder. The as-molded parts almost continuously shrank through binder removal process, except an expansion stage during 320～440℃, which is the dissolution expansion effect due to the dissolution of VPW in the polymer melt.

The rheological and shape retention properties of wax2based binders with different polymer components were studied. The effects of different polymer components on rheological, shape retention and me-chanical properties, and isotropic dimension shrinkage were investigated. The feedstock based on the PW-PP binder can not be used for injection molding due to severe separation of the binder from metal powder. The general rhelogical properties of the Fe-2Ni feedstock based on the PW-EVA binder were superior to that of the Fe-2Ni feedstock based on the PW-HDPE binder, while the shape retention properties of the PW-HDPE binder were superior to that of the PW-EVA binder. By the combination of EVA and HDPE as multi-polymer components, the PW-EVA-HDPE binder should have the best rheological and shape retention properties. The shrinkage homogeneity and mechanical properties of the feedstock based on this binder were also the best.

97W-2Ni-1Fe heavy alloy feedstocks with different powder loadings were prepared for injec-tion molding. The rheological behavior of these feedstocks was studied. The mechanical properties of as-sintered parts and the shrinkage during sintering were measured. The results showed that the rheological be-havior of these feedstocks could be described as pseudoplastic fluid. The mechanical properties of the injection molded alloy are superior to those of alloy prepared by conventional press/ sinter process. There is an optimal powder loading 47% (volume fraction) with the best mechanical properties. The shrinkage during sintering is isotropical and the tolerances of products are small.

研究了具有不同聚合物组元的几种石蜡基粘结剂和喂料的流变学性能及脱脂性能，比较了聚合物组元对其流变学性能、脱脂性能及产品力学性能和尺寸收缩性能的影响，结果表明，采用HDPE和EVA组合作为聚合物组元的PW-HDPE-EVA粘结剂具有最优性能。

The application of PIM (powder injection molding) process of cemented carbide parts bas been studied. Two kinds of cemented carbide powders, with the particle size of 3um and 0.4um respectively, were used in the experiments. Two kinds of binders were applied. The rheological properties of feedstocks were studied. The thermogravimetry analysis and thermal debinding cycles were investigated. Possible defects introduced in PIM process steps were described. The influences of holding temperature and holding time during debinding on the carbon content in compacts were studied. The mechanical properties of cemented carbide parts prepared with different partiele sized powders were compared.

Ti'/AI203 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively. By burying the explosive compaction body into a stoichiometric AI/TiO2 mixture and igniting the combustion of the stoichiometric AI/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric AI/TiO2 mixture. In this way, Ti/AI203 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the pre-heating temperatures were 298 K and 1173 K, respectively. The microstructure, composition and properties of Ti/AI203 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/AI203 FGM prepared by the explosive cornpaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: AI powder melted first, then the molten AI penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of AI powder. The reaction of gradient layers with the addition of AI203 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one.

The process of thermal debinding of injection molded water atomized 316L stainless steel powder compacts was studied in a vacuum and hydrogen atmosphere using a mercury porosimetry and the thermogravimetric analysis method. The vacuum debinding rate was investigated under the conditions of different binder compositions and temperature-increase rates, especially at the low temperature stage. The process of thermal debinding in the hydrogen atmosphere was compared with that in vacuum. It was found that the binder removal rate was much higher in vacuum than that in the hydrogen atmosphere under the same experimental conditions. The mercury porosimetry was used to measure the pore structure evolution. The results of the mercury porosimetry indicated that the pore structure evolution in injection molded compacts during thermal debinding in vacuum was greatly different from that in hydrogen atmosphere. A fine inter-connected pore structure developed as a result of the evaporation and removal of the low molecular binder components at the early stage of debinding. The reason for the difference in binder removal rate and the inter-connected pore structure in these two debinding environments lies in the difference of the vapor pressure drop, which was the vapor pressure difference between that in the molded compacts and that in the ambient environment. At the different thermal debinding stages and environments, the pore structure evolution and changes in the mean pore size in the thermally debound compacts were also different. From the low debinding temperature stage to the intermediate temperature stage of about 300 8C, the pores in the thermally debound compacts in the hydrogen atmosphere were finer and the pore size distribution was more homogeneous than that in the vacuum. At the final debinding stage, the pore size distribution was almost the same in the hydrogen atmosphere as in the vacuum.

The 1724PH stainless steel compacts sintered at 1 380 ℃for 90 min have the best me2 chanical properties and the good microstructure with homogeneously distributed pore structure and the moderate2sized grains. Whereas the compacts sintered for 60 min and 120 min show an inadequate and an over2sintered microstructure re2 spectively. The compacts sintered at 1380 ℃for 90 min have the density of 7.70g/cm3, the strength of 1275MPa, the elongation of 5%, and hardness of HRC36. With the increase of sintering temperature, the density, strength and hard2 ness increase, while the elongation decreases. The 1724PH stainless steel has good corrosion resistance, showing an activa2 tion2passivation polarization curve. But the passivation potential range is narrow and the spot corrosion potential is low, in2 dicating a low anti2spot corrosive properties.