Sample size effect and microcompression of Mg65Cu25Gd10 metallic glass

Micropillars with diameters of 1 and 3.8μm were fabricated from Mg-based metallic glasses using focus ion beam, and then tested in compression at strain rates ranging from 6×10−5to6×10−1s−1. The apparent yield strength of the micropillars is 1342–1580MPa, or 60%–100% increment over the bulk specimens. This strength increase can be rationalized using the Weibull statistics for brittle materials, and the Weibull modulus of the Mg-based metallic glasses is estimated to be about 35. Preliminary results indicated that the number of shear bands increased with the sample size and strain rates.