The effect of cryogenic treatment on the microstructure and room-temperature mechanical properties of the (HEAp/Al) at different temperatures

Abstract

At present, high entropy alloy particle reinforced aluminum matrix composites (HEAp/Al) have some shortcomings in performance. For example, it has high strength but low plasticity and processability. This paper mainly investigated how the different cryogenic temperature (−50 ℃, −100 ℃ and-196 ℃) affects the properties of (FeCoNi1.5CrCu)p/Al composites. When the cryogenic temperature drops, the maximum compression ratio (δ) and fracture energy of (FeCoNi1.5CrCu)p/Al composites enhances. The optimized − 196 ℃ sample exhibits the maximum δ of 25.21% and 5.31 × 107 J/m3 fracture energy that corresponds to high plasticity, toughness and Schmidt factor (SF). It also reaches the maximum nano-indentation and elastic modulus in the inter-diffusion layer. The enhancement of performance is attributed to its high compactness, fine HEA particles, nanometer-sized Cr precipitates around HEAP. After DCT, we can find that refined grains, massive high-angle boundary grains, induced texture are connected with the recrystallization and free energy. But those positive factors are counteracted by the significant decrease of dislocation density, which directly results in the decrease of compression strength.