###### Abstract  
The paper shows the applicability of data on the evolution of the elastic modulus measured by the instrumented microindentation technique to the determination of accumulated damage in metal matrix composites (MMCs) under high temperature deformation. A composite with a V95 aluminum alloy matrix (the Russian equivalent of the 7075 alloy) and SiC reinforcing particles is used as the research material. The metal matrix composite was produced by powder technology. The obtained results show that, under macroscopic compression at temperatures ranging between 300 and 500 \({}^{\circ}\)C, the V95\(\backslash\)10% SiC MMC has the best plasticity at 300 \({}^{\circ}\)C. At a deformation temperature of 500 \({}^{\circ}\)C, the plastic properties are significantly lower than those at 300 and 400 \({}^{\circ}\)C.  
damage; elastic modulus; microindentation; metal matrix composite; high temperatures; aluminum; 7075 alloy +
Footnote †: journal: Applied  
the most accurate. However, their practical application is inconvenient. In the metallographic method, it is rather difficult to prepare a thin section where there would be no particles of the composite matrix or the alloy phase, which result from mechanical grinding and polishing. Besides, microcracks and micropores are polished out during thin section preparation. Another methodological difficulty of the metallographic technique is the lack of reliable methods for detecting all submicropores and submicrocracks, as well as all micropores and microcracks. At the moment, the only drawback of the technique based on computed tomography data is the resolution of computer tomographs, which allow us to detect reliably defects with a linear size of above 15 \(\upmu\)m in real measurements of metal-based specimens [12; 20]. Methods based on measuring hardness and elasticity by instrumented indentation at the micro-level avoid the disadvantages of the metallographic technique; however, they have a number of other significant problems [13; 21]. As shown in [13], the technique based on hardness measurements cannot be used to calculate damage in metallic materials due to the presence of competitive processes associated with hardening and softening as a result of increasing material damage by defects. Damage determination based on elastic modulus measurements is devoid of the disadvantages of the metallographic technique caused by polishing out submicroscopic and microscopic material defects, as well as by their detection methods. Besides, the elastic modulus is weakly affected by relaxation processes and by grain shape and size [22; 23]. Nevertheless, as shown in [13; 21], the determination of the elastic modulus in metallic materials at the micro-level by the Oliver-Pharr method has a number of methodological difficulties, such as the effect of texture evolution on the elastic modulus, phase transformations during deformation and the appearance of residual stresses in materials, as well as the necessity to produce specimens with a surface plane perpendicular to the indenter. The latter problem is fairly easy to solve, but the issues related to the effect of residual stress formation, as well as texture and phase evolution, on the elastic modulus cannot be easily resolved since these characteristics represent the state of the material after deformation. The authors of [24] solved these problems for the DP600 steel using heat treatment of the specimen, which included recrystallization and recovery. Due to the thermal effect on the steel, they were able to restore the initial grain microstructure and texture and to remove residual stresses. At the same time, based on the metallographic method, the authors found that the density of specimen defects remained unchanged. This allowed them to determine specimen damage using the instrumented indentation technique. It was reported in [24] that this technique is laborious.