Abnormal internal friction in the in-situ Ti₆₀Zr₁₅V₁₀Cu₅Be₁₀ metallic glass matrix composite

Owing to the amorphous-crystalline composite structure, metallic glass matrix composites (MGMCs) usually exhibit attractive physical, mechanical and chemical properties. In the present work, we report an unusual anomalous internal friction behavior in an in-situ dendrite reinforced Ti₆₀Zr₁₅V₁₀Cu₅Be₁₀ MGMC below the glass transition temperature T_g of its amorphous matrix. According to the high-resolution transmission electron microscopy (HRTEM) images, the compelling abnormal internal friction is mainly caused by the precipitation of nanocrystals in the crystalline dendritic phase and the formation of long-period ordered phase (LPOP) in nanocrystals. Consequently, the in-situ Ti₆₀Zr₁₅V₁₀Cu₅Be₁₀ MGMC shows a propensity of annealing-induced embrittlement. Through the combined efforts from mechanical spectroscopy testing, stress relaxation experiments and structural characterization, the physical and structural origin of the unanticipated internal friction behavior is explored. Furthermore, the mechanism of the annealing induced embrittlement of the Ti-based MGMC is discussed quantitatively based on the Eshelby's theory. The current research provides the key evidence that correlates the peculiar internal friction behavior of the in-situ Ti₆₀Zr₁₅V₁₀Cu₅Be₁₀ MGMC with its mechanical properties, which is valuable to the development of the constitutive relations of MGMCs.