This paper discusses the mechanical properties of a material fabricated from commercially available metal powder mixtures designed for

use as a metal matrix of diamond impregnated composites. The mixtures with the catalogue numbers CSA and CSA800 provided by a

Chinese producer are suitable for experimental laboratory testing. The specimens were fabricated in a graphite mould using hot pressing.

The material was tested for density, porosity, hardness, and tensile strength under static loading. A scanning electron microscope (SEM)

was used to analyze the microstructure and cleavage fracture of broken specimens. It was essential to determine how the chemical

composition and the fabrication process affected the microstructure and properties of the material. The properties of the sinters were

compared with those of hot pressed specimens fabricated from sub-micron size cobalt powder (Cobalt SMS). Although the as-consolidated

material is inferior to cobalt, it displays a favourable combination of hardness, yield strength and ductility, and seems to have a great

potential for moderate and general purpose applications.

This paper deals with numerical and analytical modelling of a diamond or silicon particle embedded in a metallic matrix. The numerical model of an elastic particle in a metallic matrix was created using the Abaqus software. Truncated octahedron-shaped and spherical-shaped diamond particles were considered. The numerical analysis involved determining the effect of temperature on the elastic and plastic parameters of the matrix material. The analytical model was developed for a spherical particle in a metallic matrix. The comparison of the numerical results with the analytical data indicates that the mechanical parameters responsible for the retention of diamond particles in a metal matrix are: the elastic energy of the particle, the elastic energy of the matrix and the radius of the plastic zone around the particle. An Al-based alloy containing 5% of Si and 2% of Cu was selected to study the mechanical behaviour of silicon precipitates embedded in the aluminium matrix. The model proposed to describe an elastic particle in a metallic matrix can be used to analyze other materials with inclusions or precipitates.

This article discusses results of an analysis of mechanical properties of a sintered material obtained from a mixture of elemental iron, copper and nickel powders ball milled for 60 hours. The powder consolidation was performed by hot pressing in a graphite mould. The hot pressing was carried out for 3 minutes at 900 °C and under a pressure of 35 MPa. The sintered specimens were tested for density, porosity, hardness and tensile strength. Their microstructures and fracture surfaces were also examined using a scanning electron microscope (SEM). The study was conducted in order to determine the suitability of the sintered material for the manufacture of metal-bonded diamond tools. It was important to assess the effects of chemical composition and microstructure of the sintered material on its mechanical properties, which were compared with those of conventional metal bond material produced from a hot-pressed SMS grade cobalt powder. Although the studied material shows slightly lower strength and ductility as compared with cobalt, its hardness and offset yield strength are sufficiently high to meet the criteria for less demanding applications.

The main objective of the present work was to determine the effect of powder composition on microstructure and properties of iron-base materials used as matrices in diamond impregnated tools. The Fe-Cu-Ni powders premixed and ball-milled for 30 hours, were used for the experiments. The influence of manufacturing process parameters on microstructure and mechanical properties of produced sinters was investigated. Sintering was done by hot-pressing technique in graphite mould. The powders were consolidated to a virtually pore-free condition during 3 minutes hold at 35MPa and 900°C. Investigations of the sintered materials included: density, hardness, static tensile test and X-ray diffraction (XRD) analysis. Microstructural and fractographic observations were also made with a scanning electron microscope (SEM). The obtained results indicate that the sintered parts have a high density, close to the theoretical value, good plasticity, relatively high hardness and yield strength, and are characterized by a coarse-grained microstructure.

In this research, Co-30 mass% Cr alloys were fabricated by a vacuum hot-press sintering process. Different amounts of submicron cobalt and chromium (the mean grain size is 800 and 700 nm, respectively) powders were mixed by ball milling. Furthermore, this study imposed various hot-press sintering temperatures (1100, 1150, 1200 and 1250°C) and pressures (20, 35 and 50 MPa), while maintaining the sintering time at 1 h, respectively. The experimental results show that the optimum parameters of hot-press sintered Co-30 mass% Cr alloys are 1150°C at 35 MPa for 1 h. Meanwhile, the sintered density reaches 7.92 g·cm–3, the closed porosity decreases to 0.46%, and the hardness and transverse rupture strength (TRS) values increase to 77.2 HRA and 997.1 MPa, respectively. While the hot-press sintered Co-30 mass% Cr alloys at 1150°C and 20 MPa for 1 h, the electrical conductivity was slightly enhanced to 1.79 × 104 S·cm–1, and the phase transformation (FCC → HCP) of cobalt displayed a slight effect on sintering behaviors of Co-30 mass% Cr alloys. All these results confirm that the mechanical and electrical properties of Co-30 mass% Cr alloys are effectively improved by using the hot-press sintering technique.

In this work, nanosized Ni (nNi) powders of 50 nm are mixed with Cr and Ni submicron-powders (600 nm) to fabricate ­Cr-50 mass% Ni alloys by vacuum hot pressing. In order to evaluate the influence of the nanosized Ni powders, different amounts of nanosized Ni powders are added to produce the Cr-(50-x) mass% Ni-x mass% nNi alloys (x = 0, 10, 20 , and 30). The hot pressing was maintained at 1275°C, 48 MPa for 1 h. The microstructure evaluation, mechanical, and electrical properties were performed. The results reveal that mechanical and electrical properties are enhanced when increasing the nNi addition. The Cr-20 mass% ­Ni-30 mass% nNi presents the highest relative density of 96.53% and the electrical conductivity of 2.18×104 Scm–1, moreover, the hardness and transverse rupture strength values increase to 76.1 HRA and 1217 MPa, respectively. Moreover, a more homogeneous microstructure and a decrease in the mean grain size to 3.15 μm are acquired. Significantly, this fabrication procedure (adding 30 mass% nanosized nickel powders) results in the optimal microstructure, electrical and mechanical properties of submicron-structured Cr-(50-x) mass% Ni-x mass% nNi alloys.