Predicting the glass-forming-ability of alloys by molecular dynamics simulation: A working example of ti-co bulk metallic glasses

Predicting the glass-forming-ability (GFA) of alloys before experimental trials has long been a pursuit in the exploration of bulk metallic glasses (BMGs). Researchers can determine GFA criteria, such as reduced glass-transition temperature (Trg) and gamma factor concluded only from experimental data in prepared amorphous metals, but not beforehand. This study predicts the GFA of binary TixCo_100-x system, where x = 60, 70, 77 and 84 (hyper-eutectic, eutectic to hypo-eutectic compositions) by calculating their Trg using molecular dynamics simulation with modified tight-binding potentials. The same compositions were also melted and injection-cast into 1mm rods. Experiment tests confirm that the compositions Ti₆₀Co₄₀ and Ti₇₀Co₇₃₀, having calculated Trg > 0:5, were able to produce BMGs. Both calculation and differential thermal analysis indicate that Ti-Co BMGs have exceptionally high glass-transition temperatures.