Improving Mechanical Properties of Low-Quality Pure Aluminum by Minor Reinforcement with Fine B4C Particles and T6 Heat Treatment  
[PERSON]  
1 Department of Technological Machines and Transportation, Karaganda Industrial University, Temitatu 101400, [EMAIL_ADDRESS] (I.T. ); [EMAIL_ADDRESS] (N.A. ); 2 [EMAIL_ADDRESS] (Z.A. ); [EMAIL_ADDRESS] (K.N. ); [EMAIL_ADDRESS] (S.K.) H. T.  
production of AMCs, and convenience and ease of combination with other processes, such as ultrasonic processes, vacuum assistance, die casting, and others aimed at improving the quality of the produced AMCs [11]. In the fabrication of AMCs by stir casting, B4C particles are added to the Al matrix in the form of micrometer powders [12; 13] and nanometer-sized powders [14]. Compared to B4C particles, whose average size is \(\sim\)10-80 \(\upmu\)m, particles with sizes of \(\sim\)1-5 \(\upmu\)m and nanoscale particles are used much less frequently [11], owing to technical and economic issues. The main technical problem is the poor wettability of fine particles with matrix Al in stir casting compared with the wettability of larger reinforcing particles. At the present stage of the development of stir-casting technology, this technical problem is solvable to some extent. [PERSON] et al. [15] recently conducted a critical review and comprehensive discussion of how to solve the problem of poor wettability. The main economic challenge is the high production cost of fine particles, because the smaller the dispersivity, the higher the production cost. Simultaneously, the use of reinforcing particles with sizes \(\sim\)1-5 \(\upmu\)m and nanoscale particles, in contrast to the use of larger particles, would further improve the efficiency of, for example, such an important mechanism as Orowan strengthening [16], which directly depends on the particle dispersity. One of the possible ways to effectively solve this problem is a minor addition (weight/volume fraction \(\sim\)0.25-5%) of B4C particles, which makes it possible to improve the quality of the aluminum material without a significant increase in cost. [PERSON] et al. [17] improved the strength, hardness, and microstructure of an AA6061 aluminum alloy with a minor 4% B4C additive. Ultrasonic-assisted stir casting was used to fabricate these composites. [PERSON] and [PERSON] [18] reported improved performance of an Al-Si alloy with a minor 1% addition of B4C nanoparticles and up to 1% addition of TiO2 nanoparticles, using ultrasonic squeeze-assisted stir casting to fabricate these composites. Most Al alloys exhibit high-performance characteristics for structural applications because of the specific alloying elements in their composition. For example, Al alloys of the 6000 series [19] and other alloys are used as matrix materials for fabricating AMCs much more often than pure Al. It is well known that pure Al is too soft and lacks the strength required for most structural applications [20]. A discouraging factor for researchers may also be that pure Al is more expensive than Al alloys, although this statement is not always true, as some doping elements in Al alloys can be costly, increasing the cost of these alloys. However, pure Al has much higher ductility than most Al alloys, and if it is possible to increase the strength of pure Al, it is possible to achieve a good balance of strength and ductility, which are the main criteria for assessing the performance of AMCs and other metallic materials. There have been attempts to fabricate AMCs by stir casting using pure Al as the matrix material; however, among these attempts, there is a minimal proportion of AMCs reinforced with B4C particles. For example, [PERSON] et al.