Preparation And Properties Of ZrCuNiAlY Amorphous Alloy Under Different Technological Conditions

The preparation process has an important influence on the glass forming ability and mechanical properties of amorphous alloys.Improving the forming size and mechanical properties by optimizing the preparation process is of great significance for their application in the industrial field.In this paper,the unremelted master alloy and the arc remelted alloy were used to prepare 12mm×12mm×150mm(Zr₅₂Cu₃₂Ni₆Al₁₀)_99.5Y_0.5alloy samples at different casting temperatures（925,950 and 975℃）.The influence of preparation process on forming size,mechanical properties and thermal stability of amorphous alloys is analyzed and discussed.The results show that only the arc remelted master alloy cast at 950℃(remelting+T_casting=950℃)shows amorphous structure completely.The alloy samples obtained through the other five processes are crystallized to some extent,and the crystallization products are Cu Zr,Cu Zr₂and Y₂O₃phases.The compressive fracture strength（σ_f）and compressive strain（ε_p）of the amorphous sample prepared under the condition of remelting+T_casting=950℃are2010MPa and 3.5%,respectively.The impact toughness at room temperature is 201k J/m².This process shows the best mechanical properties.In addition,the reasons for the influence of different processes on the mechanical properties of amorphous alloys are analyzed from the perspective of free volume content.The Charpy impact toughness of(Zr₅₂Cu₃₂Ni₆Al₁₀)_99.5Y_0.5amorphous alloy from room to cryogenic temperature are studied.Although the ductile-to-brittle transition behavior is observed,the amorphous alloy still keeps a relatively robust impact toughness of 135k J/m²at-180℃,which is 69%of that at 27℃.With decreasing temperature,the fracture surface morphology changes progressively from vein pattern to periodic nanoscale wavy corrugation.Indicating that low temperature can inhibit the initiation of shear bands and promote crack propagation,which can cause low-temperature brittleness of amorphous alloys..The activation energy of the(Zr₅₂Cu₃₂Ni₆Al₁₀)_99.5Y_0.5amorphous alloy during the crystallization process under different process conditions is calculated by non-isothermal annealing experiment and Kissinger analysis method.The results show that the maximum activation energy is 138.62（k J/mol）at remelting+T_casting=950℃.The continuous heating transformation（CHT）curve is established to evaluate the long-range thermal stability.The experimental results show that the thermal stability of the sample prepared at remelting+T_casting=950℃is the highest.This is attributed to the higher casting temperature,which makes the alloy melt more homogeneous,and during the heating process,the crystal will be difficult to nucleate and grow.