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The iron alloy powder - Distaloy SE was used for the investigations. The following series of samples were studied: pure Distaloy SE (reference sample), Distaloy SE infiltrated with Cu, Distaloy SE after mechanical alloying with subsequent infiltration, Distaloy SE with the addition of 10% wt. Cu treated by mechanical alloying. The compacts were produced using two compaction pressures - 300MPa and 500MPa. The compacts were sintered under a pure dry hydrogen atmosphere at 1120oC for 45min. The heating and cooling rates were the same for all cases. The time of mechanical alloying used for investigation was 60 min. The infiltration was carried out under a pure dry hydrogen atmosphere at 1120oC for 15min with 10K/min heating and cooling rates. This paper presents the results of mechanical alloying duration and infiltration on the selected properties of sinters. The range of the research included measurements of green compacts density, sintered density, hardness as well as tribological tests (friction coefficient measurements, weight loss measurements and wear trace observations). [ABSTRACT FROM AUTHOR]

Powder of AISI 316L austenitic stainless steel modified with 0,3 wt.% elemental boron was sintered in dry hydrogen atmosphere at temperature of 1240°C. Microstructures were analyzed by means of optical and scanning electron microscope. Chemical composition of phases was determined by EDS. Obtained results were used as a basis for thermodynamic simulation of crystallization process using Scheil-Gulliver Modified solidification model Thermo-Calc software program. On the basis of experimental work it was concluded that two-step crystallization of borides during cooling from sintering temperature take place. [ABSTRACT FROM AUTHOR]

Interaction of iron and boron at elevated temperatures results in the formation of an E (Fe + Fe 2 B) eutectic phase that plays a great role in enhancing mass transport phenomena during thermal annealing and therefore in the densification of sintered compacts. When cooled down, this phase solidifies as interconnected hard and brittle material consisting of a continuous network of Fe 2 B borides formed at the grain boundaries. To increase ductile behaviour, a change in precipitates' stoichiometry was investigated by partially replacing iron borides by titanium borides. The powder of elemental titanium was introduced to blend of iron and boron powders in order to induce TiB 2 in situ formation. Titanium addition influence on microstructure, phase composition, density and mechanical properties was investigated. The observations were supported with thermodynamic calculations. The change in phase composition was analysed by means of dilatometry and X-ray diffraction (XRD) coupled with thermodynamic calculations.

The following paper describes a new and effective method to obtain high-density sinters with simultaneously decreased distortions, produced by one press and sinter operation. This effect was achieved through the induced disappearance of the eutectic liquid phase. The study was carried out on AISI 316L stainless steel powder that was mixed with elemental boron and silicon nitride. Boron was used as a sintering process activator. The scientific novelty of this publication consists of the use of a silicon nitride as a solid-state nitrogen carrier that was intended to change the borides' morphology by binding boron. Based on the thermodynamic calculations, 20 blends of various compositions were tested for physical properties, porosity, microstructure, and mechanical properties. Moreover, phase compositions for selected samples were analyzed. It was shown that the addition of silicon nitride as a nitrogen carrier decreases the boron-based eutectic phase volume and both increases the mechanical properties and decreases after-sintering distortions. An explanation of the observed phenomena was also proposed.