Abstract
The paper deals with some experimental methods carried out in order to determine the properties of the composition material designed for intake valve seat, in order to improve the performances of thermal transfer. The precise knowledge of the physical, chemical and technological properties of the metallic powders is very important from the point of view of the manufacturing technology, as well as for ensuring the quality and the properties required at the products obtained from these powders. In order to obtain the corresponding technological and mechanical technologies, a decisive role is held by the applied compacting presssure, which determines the compactness, respectively the pressing porosity. The following investigation means are reviewed in this paper: the study of the structural characteristics by the diffraction of X-rays, methods for the determination of the mechanical properties, methods for testing the semiproducts formed of metallic powders, methods for the determination of the thermal properties (photo-accoustic method), measurement of the thermal conductivity (thermocouples, Bock´s device). The aim of the research is to study and obtain new materials for sub-assemblies and machine-tools specific for the internal combustion engines, with upgraded properties of thermal transfer as compared to the alloys used on a large scale. The synthesis of some "atomic clusters" from metals by the method of the condensation in gas, followed by the in situ consolidation, under high vacuum conditions, led to the production of a new class of materials with ultra-fine grains. These materials have special properties, often upgraded as compared with the conventional materials.From this reason, a real science of both metallic and non-metallic powders metallurgy has developed in the last 20 years. The use of these materials in industry determines economies of non-ferrous metals and makes possible the simplification of the manufacturing technology and reduces the production losses. The subsequent upgrading of these materials will be oriented towards the optimization of the static strength.
Keywords: internal combustion engines, new materials, atomic cluster