Sintered composites of Al-8wt%Cu-10vol%SiCp were deformed by repressing or equal channel angular pressing(ECAP) at room temperature, and . Repressing produced more densification than ECAP but resulted in much lower transverse rupture strengths. In both cases, deformation at room temperature and , resulted in much lower strengths than deformation at , and also caused the fracturing of some SiC particles. The higher bend strengths and less SiC fracturing at are attributable to the presence of an Al-Cu liquid phase during deformation. The employment of copper coated SiC instead of bare SiC particles for preparing the composites was found not improving the properties.

To co-fire with commercial LTCC (Low Temperature Co-fired Ceramic) materials at , different contents of were added to the (BZN) ceramics. According to the test results, the cubic phase of BZN was transformed into orthorhombic in all the test materials. phase was formed in test materials with of addition. The phase transformation of cubic BZN was controlled during the synthesis process with excess ZnO content. The Cubic and orthorhombic phases of BZN could coexist and be sintered densely at .

Effects of sintering conditions such as sintering temperature and heating rate on oxygen content, density, microstructure and toughness of sintered Mo were investigated. The oxygen content of the sintered Mo significantly depended on the sintering conditions. The oxygen content of the primary sintered(below 1673 K) Mo influenced the densifications. The number of pores at grain boundaries of the secondary sintered(at 2073 K)Mo depended on the oxygen content of the primary sintered Mo. Grain growth of the secondary sintered Mo was inhibited by the existence of pores at the grain boundaries. The secondary sintered Mo having larger number of pore and smaller grain size demonstrated higher strength.

Dry sliding wear behavior of electro-pressure sintered Co-Fe, Co-Ni and Co-Fe-Ni compacts was investigated. Pin-on-disk wear tests were performed on the sintered compacts disk specimens against alumina and silica ball counterparts at various loads ranging from 3N to 12N. Two sliding speeds of 0.1m/sec and 0.2m/sec and a fixed sliding distance of 1,000m were employed. Worn surfaces and cross sections of them were examined by a scanning electron microscopy, and wear mechanism of the compacts was investigated. Effects of the oxide layer that was formed on wearing surface of the compacts on the wear were also studied.

The microstructure and electrical conductivity of CNTs dispersed nanocomposites depending on the powder processing and CNTs content were demonstrated. The composite powders with homogeneous dispersion of CNTs could be synthesized by a catalytic route for direct formation of CNTs on nano-sized Fe dispersed powders. The sintered nanocomposite using the composite powder with directly synthesized CNTs showed homogeneous microstructure and enhanced elelctrical conductivity. The influence of powder processing on the properties of sintered nanocomposites was discussed by the observed microstructural features.

The oil-impregnated sintered bearings are used for various aplecations and, wide usages without refueling. The oil circulating mechanism operates smoothly the behavior of oil If doing at the time of passing and becoming a stationary state, and there is little thing where trouble is caused. On the other hand, the trouble of such as starting noise might be caused in the unstationary state that repeats operation for a short time. To study the behavior of oil of each parameter, we execute the numerical simulation and various verification experiments. As a result, we developed that the bearings were able to be used enough for various brief operating time in the unstationary state. Finally we have expanded the usage of the oil-impregnated sintered bearings by adding the consideration of the behavior of oil.

The processes of P/M affect the properties of sintered gears. The different techniques of P/M lead to the different properties of sintered gears. This paper summarizes new progress in powder metallurgy for sintered gears. These progresses include warm compaction, high velocity compaction, sinter hardening, high temperature sintering, infiltration, CNC powder press and surface densification etc.

This research reports for the successful consolidation of Al2O3 powder with retained ultra-fine structure using MPC and sintering. Measurements in the consolidated Al2O3 bulk indicated that hardness, fracture toughenss, and breakdown voltage have been much improved relative to the conventional polycrystalline materials. Finally, optimization of the compaction parameters and sintering conditions will lead to the consolidation of Al2O3 nanopowder with higher density and even further enhanced mechanical properties.

The injection molded Fe sintered bodies were fabricated using two kinds of nano Fe powders, Fe-5%vol.ZrO2 and Fe-10vol.%ZrO2 powders. The relationship between microstructure and mechanical properties depending on the ZrO2 contents and sintering temperature were characterized by SEM and TEM techniques. In the wear test, the Fe-0vol%ZrO2 sintered bodies showed mainly adhesive wear, but in the Fe-5%vol. ZrO2 and Fe-10vol. % ZrO2 composites the main wear behavior showed abrasive wear mode.

The mechanical properties of sintered low alloy steels were analysed using Finite Element Methods (FEM), in which the powder is modelled as an elastic–plastic continuum material. A quantitative analysis of microstructure was correlated with tensile and fatigue behavior to understand the influence of pore size, shape, and distribution on mechanical behavior. Tensile strength, Young’s modulus, strain-to-failure, and fatigue strength all increased with a decrease in porosity. The decrease in Young’s modulus with increasing porosity was predicted by analytical modeling. Two-dimensional microstructure-based finite element modeling showed that the enhanced tensile and fatigue behavior of the denser steels could be attributed to smaller, more homogeneous, and more spherical porosity which resulted in more homogeneous deformation and decreased strain localization in the material. The relationship between relative density of P/M steels and mechanical behavior is also obtained from FEA and compared with the experimenta data. Good agreement between the experimental and FEA results is observed, which demonstrates that FEA can capture the major features of the P/M steels behaviour during loading. The implications of pore size, morphology, and distribution on the mechanical behavior and fracture of P/M steels are discussed. It is therefore demonstrated that FEA can predict the possible mechanism of failure during loading.

The sintered parts are mainly used for automobile industry, and a part of air conditioners. In automobile industry, the application range of sintered parts is very broad and use for a driving and a lubricating system. And air conditioner uses them for compressor. Grinding of compressor and pump parts is very difficult these days, because these parts use High hardness materials and require high precision grinding. Tool life has to be extended to decrease production cost. We analyzed processing mechanism and developed new grinding wheels for Double Disk Grinding. And, we introduce new truing technology that improved tool-life and precision.

Manganese is an alloying element that improves the hardenability of steels. It could be a valid substitute in sintered steels, increasing mechanical properties. The hardenability of three low alloy Mn steels was studied to establish the influence of manganese on the heat treatments. The Grossmann approach was adopted, which uses cylinders with different diameters to induce different gradients of cooling rate in the cross section. The correlation of microstructure and microhardness to the actual cooling rate makes the results independent on the process parameters and applicable to each industrial condition, once the actual cooling rate in the parts is known.

Homogeneous microstructures of the PM compacts are difficult to attain when mixed elemental powders are used. This study examined the microstructures of pressed-and-sintered and MIM products that contain Ni and Mo.Ni-rich areas, which were lean in carbon and were soft and were found easily in regular specimens. Gaps or cracks near the Ni-rich or Mo-rich areas were also frequently observed. This problem worsened when Ni and Mo particles were large and were irregular in shape. By using ball milling treatment and ferroalloy powders, the microstructure homogeneity and mechanical properties were improved. The addition of 0.5wt%Cr further improved the distribution of Ni because Cr reduced the repulsion effect between nickel and carbon. With the elimination of Ni-rich areas, more bainites and martensites were formed and mechanical properties were significantly improved.

The effect of individual gas constituents in a sintering atmosphere is examined to optimize the sintered properties of Iron-Carbon P/M components. The influence of sintered properties is reviewed as a function of hydrogen percentages and dew point in the sintering zone. Microstructures, porosity, pore morphology and dimensional changes are the subject of this review. The effects of CO containing atmospheres are compared against the non CO atmospheres in terms of hardness, carbon control and dimensional changes.

Wrought Si-steels are generally used for electromagnetic valves, which are needed good response. To date, Hitachi Powdered Metals Co., Ltd. have produced Fe-Si base sintered magnetic material, EU-52, which shows a magnetic flux density of more than 1.25T at 2000A/m and a maximum permeability of more than 3500. However these magnetic properties are lower than that of wrought Si-steels. Because EU-52 has a low density of 7.2Mg/m3. For improving the magnetic properties, it is necessary to increase the density of sintered cores. To increase density, a new mixing method of coating fine Si powders on atomized iron powders was developed, for avoiding the Kirkendall effect. As the result, developed P/M Fe-Si magnetic cores shows higher density of 7.38Mg/m3, higher magnetic flux density of 1.48T at 2000A/m and higher maximum permeability of 6800.

The fracture behavior and mechanical characteristics of sintered rare-earth magnets were investigated. It shows that the fracture behavior and bending strength of the magnets obviously exhibit anisotropy. Sm-Co magnets tend to cleavage fracture in the close-packed (0001) plane or in the (10 11 ) plane. The fracture mechanism of Nd2Fe14B magnet mainly appears to be intergranular fracture. The anisotropy of fracture behavior and mechanical strength of sintered rare-earth magnets is caused mainly by the strong crystal-structure anisotropy and the grain alignment texture. The effects of Nd content, and Pr, Dy substitution on the impact stability of Nd2Fe14B magnets were also reported.

A new method has been developed to fabricate microcomponents by a combination of photolithography and sintering of metallic powder mixtures, without the need for compression and the addition of Mg. This involves (1) the fabrication of a micromould, (2) mould filling of the powder/binder mixture, (3) debinding and (3) sintering. The starting powdered materials consisted of a mixture of aluminium powder(average size of 2.5 um) and alloying elemental powder of Cu and Sn(less than 70nm), at appropriate proportions to achieve nominal compositions of Al-6wt%Cu, Al-6wt%Cu-3wt%Sn. This paper presents detailed investigation of debinding behaviour and microstructural development.