Effect Of Process Parameters On Structure And Properties Of Zirconium-based Amorphous Alloys

To study the effects of different process parameters on the structure and properties of amorphous alloys,a four-factor four-level orthogonal experiment was designed for alloy formulation with composition[Zr_0.72-x(Cu_0.59Ni_0.41)_0.28+x]_88-yAl_12+y.In condition of various process parameters(component,cooling rate,superheating temperature,etc.)in the preparation process,the pending test amorphous alloy samples were prepared,and subsequent structural characterization and basic performance testing of prepared samples were executed.Results manifests that the amorphous alloy with the composition of[Zr_0.73(Cu_0.59Ni_0.41)_0.27]₈₈Al₁₂and the composition of[Zr_0.73(Cu_0.59Ni_0.41)_0.27]₈₇Al₁₃demonstrate superior performance with corresponding preparation parameters,meanwhile,it can be observed that the content change of aluminum plays a vital role on the compressive strength,according to orthogonal analysis of experimental results,the content change of zirconium,nickel,copper and the cooling rate of the melt during alloy preparation possess greater influence on the plastic properties of the alloy,and the supercooled liquid region scope of the alloy is guided by superheat temperature of the melt during alloy preparation.Thermal simulation compression experiments of the amorphous alloy[Zr_0.73(Cu_0.59Ni_0.41)_0.27]₈₇Al₁₃were conducted,results manifested that the optional thermoplastic processing parameters for the alloy are temperature of 420??430?,and a strain rate of 10^-3s^-1.Based on the identical process parameters in the light of different mass ratios according to the selected components[Zr_0.73(Cu_0.59Ni_0.41)_0.27]₈₈Al₁₂and[Zr_0.73(Cu_0.59Ni_0.41)_0.27]₈₇Al₁₃,Industrial grade sponge zirconium and high-purity zirconium blocks were used for preparing mixed purity alloys.Related research on alloys shows that the amorphous alloy cannot be prepared with the addition of sponge zirconium in the component,and the compression process is characterized by typical brittle fracture,low compressive strength and no plastic strain.With the trace addition of the rare earth element yttrium to the above components,the glass forming ability of the above compositions were greatly improved,and the prepared alloy of the same composition possess a completely amorphous structure.Compression experiments show that the compressive strength and plasticity of the amorphous alloy[Zr_0.73(Cu_0.59Ni_0.41)_0.27]₈₈Al₁₂were completely restored,the compressive strength and ductility of amorphous alloys with composition of[Zr_0.73(Cu_0.59Ni_0.41)_0.27]₈₇Al₁₃were ameliorated similarly,and the same is true for microhardness.To further study the changes of structure and properties,the above-mentioned amorphous alloys prepared by adding a small amount of element yttrium and the same kind of amorphous alloys prepared from completely high-purity zirconium without adding yttrium were further subjected insulation treatment at the temperature of supercooled liquid region.Research demonstrates that degrees of crystallization went with insulation treatment,especially the amorphous alloys which contains more sponge zirconium,thus,accompanying is the reduction in compressive strength of alloys,and evolution of brittle fracture,which shows high sensitivity to ambient temperature while eliminated the adverse effects of impurities in sponge zirconium on the glass forming ability of alloys.