PSI - Issue 65

A.S. Smirnov et al. / Procedia Structural Integrity 65 (2024) 255–262 A.S. Smirnov, A.V. Konovalov,V.S. Kanakin and I.A. Spirina/ Structural Integrity Procedia 00 (2024) 000–000

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(carbides, oxides, graphene, etc.) acting as the reinforcing material. As a rule, a synthesized metal matrix composite for structural purposes has low plasticity after manufacture (Smirnov et. al., 2018; Nie et. al., 2017; Qiao et. al., 2016). As a result, high-temperature deformation is performed in order to attain the required shape and mechanical properties of a part. Under deformation at high temperatures, competing hardening and softening processes take place simultaneously in the matrix of a metal matrix composite. Hardening is usually associated with an increase in the density of dislocations, and softening is caused by their decrease through dynamic recovery and recrystallization. This course of hardening and softening leads to the fact that the rheological behavior and the formed microstructure depend on the entire loading history, and this makes it necessary to build rheological models and microstructure formation models that take into account the loading history of the material. A flow stress model was constructed in (Smirnov et. al., 2015). That model described the viscous and plastic properties of the medium, the processes of plastic hardening caused by the increment of dislocation density and blocking of the motion of free dislocations by particles, as well as softening resulting from dynamic recovery and recrystallization. The model was widely tested on aluminum alloys. However, the testing of that model describing the rheological behavior of aluminum matrix composites at high temperatures was limited only to the AlMg6\10% SiC composite (Smirnov et. al., 2020). The purpose of this study is to test the possibility of simulating the rheological behavior of the V95\3% TiC metal matrix composite using the mathematical model previously constructed in (Smirnov et. al., 2015), which describes the processes of hardening and softening through dynamic recovery and recrystallization. The dispersion-strengthened V95\3 vol.% TiC aluminum matrix composite was made using an ex-situ liquid phase technology (Kurganova, et. al., 2020; Ramanathan et. al., 2019; Annigeri Ulhas et. al., 2017) by introducing a mixture of TiC and Ti powders into the melt. Both powders were mixed in a mortar for 15 minutes. The mass ratio of titanium carbide powder to titanium powder was 3:1. The resulting powder mixture was introduced into the molten V95 alloy at a temperature of 820 °C, with a running stirrer, at a frequency of 300 rpm. The stirrer had 4 blades tilted at an angle of 45°, and it was made from titanium coated with titanium carbide in order to prevent the interaction of the melt with the stirrer material. The mixing time for the melt with the particles was 10 minutes, the melt with the particles being thereafter poured into a metal mold heated to 450 °C. To prevent the interaction of the melt with the environment, the mixing was carried out in an argon medium. The ingots were heated in a crucible by means of an induction furnace. The fractional composition of the titanium carbide powder was certified by means of the Lasca-TD laser analyzer, and it corresponded to the F800 fraction with an average particle size of 7.5 µm. The particle shape was studied in a Vega II Tescan scanning electron microscope (Fig. 1a). The grain microstructure of specimens before deformation was determined from the data obtained by the electron backscattered diffraction (EBSD) method in a Vega II Tescan scanning electron microscope with an Oxford HKL Nordlys F+ EBSD analysis accessory (Fig. 1b). The particle distribution in the composite matrix was studied by optical microscopy (Fig. 1c,d). For the analysis of the grain microstructure, the specimens were first mechanically polished and then ion polished in a Linda SemPrep2 ion etching system for 30 minutes at an accelerating voltage of 10 kV with an angle of inclination of the specimen to the ion beam equal to 7  . It was believed that the grains had a misorientation of more than 15° and that the misorientation of the subgrains ranged from 2 to 15°. 2. The mathematical model, material and research technique