CRYSTALLIZATION BEHAVIOR OF ANNEALEDZr ₅₅ Cu3oAl1oNi ₅ BULK METALLIC GLASSDURING PULSED LASER REMELTING

Abstract

The crystallization behavior of annealed metallic glasses during pulsed laser remelting was investigated in this work. The as-casted Zr 55 Cu 30 Al 10 Ni 5 bulk metallic glasses were annealed at 390, 430, 530, 792 and 902 £ separately. And then these annealed alloys were remelted by pulsed laser. The experiment results show that the alloys annealed at 390 and 430 £ were still metallic glasses, and their crystallization behavior during remelting is similar to the remelting of metallic glass without annealing treatment. The specimens annealed at 530, 792 and 902 £ were completely crystallized.After remelting, the molten pools of these specimens were amorphous. For the specimens annealed at 530 and 792 £, there was no obvious epitaxial growth at the bottom of molten pools. For the specimens annealed at 902 £, there was little primary phase epitaxial growth at bottom of molten pool after one time laser remelting while without epitaxial growth after 11 times laser remelting. The epitaxial growth was caused by the area reserved the composition distribution of CuZr 2 primary phase during laser remelting. So it is hard to obtain epitaxial growth during laser remelting for Zr 55 Cu 30 Al 10 Ni 5 *