Shishkina Y. Improvement of the processes of obtaining aluminium-based composites based on the Al-TiC system by the methods of thermal synthesis and hot forging

The work is devoted to the solution of the actual scientific and technical problem of development and improvement of technological processes for the production of aluminum composites of functional purpose. The analys of the influence of technological schemes and modes of obtaining materials on the peculiarities of their structure formation and basic physical, mechanical and operational properties have been carried out. The presence of TiC and tanium-aluminum complex carbides (ternary carbides) were determine after thermal synthesis. The predominant strengthening phase in specimens with high carbon content (10 ÷ 13%) is titanium carbide, in samples with minimal carbon content (6%) and relatively high aluminum content (40%) in the structure of the synthesized material predominant disordered elongated needle-like grains of complex ternary titanium-aluminum carbides. A technological scheme for the production of aluminum matrix composites by the method of hot forging is developed, the regularities of the processes of their structure formation in the volume of consolidated billets, physical and mechanical properties, tribotechnical properties and corrosion resistance have been investigated. It is shown that with increasing content of the master alloy component in the material, both hardness and strength characteristics of the specimens increase monotonously, and the parameters of plasticity naturally decrease. The results of complex tribotechnical tests of hot forged aluminium composites showed that the best characteristics are composites of 15% carbid-thitanium master alloy with 5 to 6% copper additives, which provide almost 2 times the wear resistance at a stable friction coefficient (0,3 ÷ 0,45) in comparison with composites, the matrix phase of which copper is not doped. Investigation of the corrosion resistance of the obtained materials in a 3.5% solution of NaCl showed that their corrosion resistance is 1 point (absolutely stable), which significantly exceeds the corrosion resistance of aluminum and one of the most widely used aluminum alloys 1160. The results of complex theoretical and experimental researches were found to be practical application in the technological processes of manufacturing a number of parts of automotive and aviation engineering, in particular - the piston of the automotive compressor, the work of the blade of the fan of the aircraft engine.