“Extended” shear bands in interior of Pd-based bulk metallic glasses

Shear bands in the interior of Pd₇₉Cu₆Si₁₀P₅, Pd₇₉Cu₃Ag₃Si₁₀P₅, and Pd₇₉Cu₄Au₂Si₁₀P₅ bulk metallic glasses were investigated by optical microscopy (OM) and scanning electron microscopy (SEM). No shear bands can be observed in the samples before etching. By etching in aqua regia solution, shear bands are found to be susceptible to preferential etching, and multiple etched bands could be observed. The thickness of the etched bands is about 1–7 μm. Therefore, the preferentially etched shear bands found in the study are called the “extended” shear bands. The “extended” shear bands can be divided into three classes according to their features: early, developing, and well-developed “extended” shear bands with thickness of about 1, 5, and 7 μm, respectively. The interface between the well-developed “extended” shear bands and the matrix is clearer than that of the others.