Badania zjawisk na granicy faza wzmacniająca-osnowa w kompozytach otrzymanych z proszków aluminium

W pracy poruszono zagadnienie badania zjawisk na granicy faza wzmacniająca-osnowa w kompozytach otrzymanych z proszków stopów aluminium w procesach przeróbki plastycznej na gorąco. Zwrócono uwagę na rolę badań metalograficznych oraz możliwość wykorzystania metod symulacyjnych do analizy stanu odkształcenia w osnowie, w otoczeniu fazy wzmacniającej.

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The work covers research on phenomena of boundary reinforcing phase-matrix in the composites obtained from P/M aluminium alloys in the hot forming processes. The role of metallographic research and possibility of application of simulation method to the analysis of deformation state in the matrix were underlined. The powder particles used in the research are shown in fig. 1. Sporadic pores can be observed in the particles as well as oxides on their surface. Saffil fibres (2.5:1.0% vol.) and Nextel 610 and Nextel fibres 720 (5% vol.) served as the reinforcing materials of the matrix (fig. 2). The fibres and matrix were wet-mixed. The preforms were produced by cold pressing of the mixture. In effect of extrusion at (he temperature of 500°C with A = 13.32 materials with a high density were obtained. Metallographic analysis with the optical microscope of the extruded materials confirm high densification of the matrix (fig. 3 and 4). The structure is fine-grained and no huge, numerous pores can be observed. A part from the fibres, there are also dispersed oxides and phase precipitations. The state and distribution of the fibres in the matrix and their surroundings pores the quality of their joint (fig. 5). The fibres on the destruction surface are distributed evenly in the matrix. The areas of larger deformations of matrix in the nearest surroundings of the fibres show that during the formation of the destruction surface the fibres took part in the reinforcement of the material. Fig. 6 show Saffil fibres in the composite on the matrix of AI-1.85%Cu-1.9%Mg-1.11%Si-0.47%Ni alloy. The fibres remain contact with the metallic matrix precipitations of O phase and the oxides. Figure 6b shows the matrix with dislocations in the surroundings of the fibres. In the modelling of the deformation of the composite it was assumed that the composite consist of soft matrix and undeformable particles. The distribution of the equivalent strain after deformation is shown in fig. 7. There exists concentration of deformation before the hard particle in direction of resultant of the flow field of velocity (fig. 7a) and generation of deformation fields between the particles in the matrix.