PSI - Issue 65

E.G. Zemtsova et al. / Procedia Structural Integrity 65 (2024) 317–323 E.G. Zemtsova et al. / Structural Integrity Procedia 00 (2024) 000–000

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2. Materials and methods

2.1. Production of an Al based bulk composite reinforced with TiC nanostructures

Al samples are cast on an induction vacuum compression casting machine ULVK-30A, manufactured by Spark Don LTD (Russia), equipped with an autonomous water cooling module MAVO-3. Due to the workability in a vacuum or a protective atmosphere, ULVK-30A provides high-quality casting, while maintaining the physico chemical properties of the alloy unchanged after melting. And the use of an induction furnace reduces the heating time of the injection molding material. During the casting, we used pre-prepared compacts, which are material tablets, including a dispersed matrix of the future composite and a reinforcing phase. To melt the samples, we selected a vacuum melting mode with a pressure in the melting chamber of less than 250 mbar and a constant flow of argon. Preliminary, the chamber was purged with compressed argon to remove traces of air. This leads to the formation of a protective environment in the melting and casting chambers. The minimum weight of the workpiece was chosen at 3.2 g. If necessary, the loading of raw materials can be increased by a multiple of the weight of the standard workpiece and amount to 3.2 g*n, where n is the number of loaded blanks. The casting temperature for aluminum raw materials was selected experimentally as 700 °C. The resulting samples of injection molding materials were further machined. On a spark-cutting machine, plates of material were made from ingots, which were further studied. The synthesis of the reinforcing phase of TiC nanostructures on the surface of dispersed aluminum was carried out by chemical assembly. Titanium isopropoxide vapors enter the reaction zone with the substrate from one of the containers, the vapors interact with the active groups of the surface, as a result, the hydroxyl group is replaced by an isopropoxide one. The treatment was carried out for 15 minutes, then propylene glycol was also supplied to the system for 15 minutes. The next step in the synthesis of particles of the reinforcing phase is carbonation in an inert helium atmosphere at 600 °C for 1 h. As a result of the synthesis, samples of Al powder with various carbide amounts deposited on the surface were synthesized. The increase is 0.5 nm per one reaction cycle.

2.2. Characterization

X-ray phase analysis was performed on a Bruker "D2 Phaser" powder diffractometer. The phases were identified using data from the International Centre for Diffraction Data. The composite material structure and elemental analysis were studied using a Zeiss Merlin scanning electron microscope with additional attachments for X-ray microanalysis Oxford Instruments INCAx-act.

2.3. Mechanical tests, uniaxial tensile tests

Uniaxial stretching was performed on a Shimadzu AG-50kNX testing machine at room temperature, the deformation rate was 5•10 -4 s -1 . The samples deformation was controlled by a TRViewX 55S video extensometer. Bending was tested in accordance with GOST 14019-80 "Metals and alloys. Methods of testing for binding". From the samples obtained, double-sided blades with a working part size of 6*2 mm were made on the ART 123 PRO electroerosion machine of NPK Delta-Test LLC. The ends of the blades were examined using a side-illuminated Micmed-6 microscope in order to control the integrity of the samples.

3. Results and discussion

3.1. Production of a metallic composite with two hardening modifiers

For mechanical tests of an Al matrix composite, Al particles were used as a reinforcing phase after two cycles of carbide nanostructures layering. The composite was obtained by introducing particles of the reinforcing phase of the Al@TiC composition into the initial Al matrix in a ratio of 1:99.5:95 wt. %.