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The use of mechanochemical activation of metal powders, as well as their mixtures, in planetary mills opens up broad prospects for the creation of new nanocomposite materials. A characteristic feature of this type of activation is that, after it is used to process mixtures, the particle morphology, size, and phase composition change. Ti–Cu nanocrystalline materials, synthesized by mechanical alloying of elemental Ti and Cu powders, have long attracted the attention of researchers due to their numerous applications in the military, industrial, automotive manufacturing, and aerospace sectors. In addition, in modern medicine, titanium is widely used to manufacture implants that replace hard tissues. The hardness of pure titanium ranges from approximately 0.7 GPa to 1.2 GPa, while that of the Ti-6Al-4V titanium alloy ranges from 3.0 to 3.7 GPa. It should be noted that in industrial casting, the hardness of pure titanium doubles when alloyed with copper or silver.
In this study, Ti–10%Cu nanocomposites were synthesized in a planetary high-energy ball mill from elemental Ti and Cu powders. Elemental titanium (Ti) and copper (Cu) powders with a purity of 99.6% and an average particle size of 100 μm were used. Mixtures of the initial Ti and Cu powders were processed cyclically (cycle time: 5 minutes) in a planetary high-energy ball mill for 120 minutes. The temperature of the working area inside the mill jars did not exceed 100°C during processing. The rotational speed of the jars is 1480 rpm, the acceleration is 50 g, and the pressure on the particles of material in the cups is on the order of 5 GPa. The mechanically activated powder mixtures were compacted in a mold under a pressure of 30 GPa, after which they were sintered in an argon atmosphere at a temperature of 950°C for 30 minutes. Meyer hardness was determined, which is the average pressure on the contact surface between the indenter and the specimen. The load varies from 0 to 100 grams according to a simple “load–unload” cycle. The mechanical properties of the Ti–Cu nanocomposites obtained were analysed. It should be emphasized that the hardness of the Ti–Cu materials obtained in this study is higher than that of traditional bulk alloys. For example, when a 100-gram load was applied to the indenter, the hardness of the Ti-10%Cu nanocomposite was 4.7 GPa. This impressive result is primarily due to the nanostructured state formed during the mechanical grinding process. However, the Young’s modulus of the resulting Ti–Cu nanocomposite is lower than that of the bulk alloy and is equal to 50 GPa. The resulting Ti-Cu nanocomposite, with a hardness of 4.7 GPa, can be used not only in industry, automotive manufacturing, and the aerospace sector, but also in the military for use in armor plates. While the Ti-Cu nanocomposite corresponds to mid-grade armor steel, it offers significant advantages due to the lighter weight of the armor plates.
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