Crystallization And Compression Properties Of Zr₅₅Al₁₀Ni₅Cu₃₀ Bulk Metallic Glass

Zr₅₅Al₁₀Ni₅Cu₃₀ bulk amorphous alloy is chosen as the experimental alloy because of its strong amorphous forming ability and crystallization stability. The glass forming ability, crystallization kinetics and mechanical properties of Zr₅₅Al₁₀Ni₅Cu₃₀ bulk amorphous alloy has been investigated after annealed at different technological parameters.The structure of Zr₅₅Al₁₀Ni₅Cu₃₀ alloy and precipitated phases of annealed alloy was investigated by XRD. During the crystallization process, the tetragonal Al3Zr is firstly precipitated, then the stable tetragonal Zr₂Cu, cubic NiZr₂ were precipitated. With the increase of annealing temperature and annealing time, the precipitated phase is complicating and the crystallinity is increasing, the grain size of the precipitated phase is also increasing.The crystallization kinetics of Zr₅₅Al₁₀Ni₅Cu₃₀ bulk metallic glass was investigated by means of DSC under nonisothermal conditions. The effective activation energies for the crystallization of Zr₅₅Al₁₀Ni₅Cu₃₀ bulk metallic glasses were evaluated by Kissinger′s equation. The effective activation energies after annealing are higher than the as-quenched alloys', which approved the annealed alloy have better thermal stability.The strain rate of the compressive experiment is 0.005mm/s. The fracture strength and strain of 603K, 0.5h,603K, 5h,653K, 0.5h and 683K, 2h are 1885MPa, 7.5%,1721MPa, 7.3%,1391MPa, 10.0% and 1292MPa, 6.3%. The fracture strength of 603K, 0.5h is the best and has an increase of 51.7 percent to the as-quenched alloy's 1242MPa.The fracture mode of annealed alloy at low temperature is similar to the as-quenched alloys', the sample fractures nearly along 40°direction of pressure axis and shear deformation occurred. The fracture morphology is veiny pattern and the fracture mode is brittle fracture. The fracture mode of completedcrystallization alloy is multiple cracking and the fracture morphology is irregular.