The effect of matrix fracture toughness on the plastic deformation of the metallic glassy composite

In the present study, two kinds of bulk metallic glasses (Zr ₅₅Cu₃₀Al₁₀Ni₅ and Cu ₄₆Zr₄₂Al₇Y₅) with high strength and no plastic strain were adopted as matrixes. Both of them were reinforced by ductile crystalline TiNb with the same volume fraction and particle size. The compression results showed that the plastic strain of TiNb/Zr ₅₅Cu₃₀Al₁₀Ni₅ composite was higher 292% than that of TiNb/Cu₄₆Zr₄₂Al₇Y₅ composite. It should be related to the fracture toughness of the glassy matrix. For the glassy matrix with high toughness, the formation of shear bands and micro-crack at the front of the crack reduced the energy of main crack development. It resulted in a large plastic strain. On the other hand, for the brittle metallic glassy matrix, crack developed quickly through the cross section so that no more shear bands was formed. It resulted in the failure of the sample with smaller plastic strain.