The thermal stability and mechanical behaviors of Zr–Cu–Ni–Ti–Be bulk metallic glasses

Four compositions of Zr–Cu–Ni–Ti–Be bulk metallic glasses with 3 mm in thickness were made by arc melting and die casting processes. The transformation temperature and activation energies of Tg and Tx points of these alloys were examined and calculated, also the hardness and high-temperature elastic modulus of these alloys were analyzed. Results revealed that the increasing of Be-content could increase both of the Tx and ΔT (ΔT = Tx1−TgTx1−Tg). Tx1Tx1 increased from 640 to 691 K and the ΔT increased from 24 to 61 K while the Be-content increased from 11.9 to 27.5 at.%. These exhibited that increasing the Be-content resulted in increasing the glass formability of the alloys in the present study. The activation energies of Zr38.5Cu15.25Ni9.75Ti16.5Be20 had a lowest value of 165 kJ/mol among these metallic glasses. Also, increasing the Be-content could enhance the oxidation resistance. In addition, the bulk metallic glasses with the Be-content more than 20 at.% would decrease their high-temperature thermal stabilities. The results showed that the Zr–Cu–Ni–Ti–Be alloys with more than 20% of Be-content would crystallize while they annealed at elevated temperature for several hours, even though the annealing temperatures were lower than the Tx point.