Composition Design Of The Zr-Cu-Al-Y Metallic Glasses And The Study On Their Glass-forming Ability

The Zr-Cu-Al ternary system has strong amorphous forming ability and good application performance,and is one of the most studied systems.It is well known that the addition of an appropriate amount of rare earth elements can improve the amorphous forming ability of the alloy,and improve their thermal stability and mechanical properties.Based on this,I chose the Zr-Cu-Al-Y quaternary system containing rare earth element Y.The amorphous alloy formation ability was predicted by phase diagram thermodynamics,and verified the amorphous forming ability of the predicted components through experiments.This research can provide some theoretical and experimental basis for the design of amorphous alloy compositions.Mainly carried out the following work:The thermodynamic data of Al-Zr,Al-Y,Zr-Y,Zr-Cu and Cu-Y binary systems in the literature were evaluated.The thermodynamic parameters in the literature were used to extrapolate the thermodynamic description of Zr-Al-Y and Zr-Cu-Y by using the CALPHAD technology.of.Optimized the two boundary ternary systems of Zr-Al-Y and Cu-Zr-Y by using the phase diagram calculation CALPHAD?CALculation of PHAse Diagram?technology.Combined with the existing thermodynamic parameters of Al-Cu-Y and Zr-Cu-Al,established an accurate and reliable thermodynamic description of the Zr-Cu-Al-Y quaternary system by extrapolation and calculation.Calculated that there are105 invariant reactions in this system.Four deep eutectic compositions were designed based on the deep eutectic criterion.Amorphous was prepared by single roll melting and copper die casting.The samples were analyzed by X-ray diffraction?XRD?and differential scanning calorimetry?DSC?.The phase structure and the phase transition temperature point were found to be Zr₄₀Cu₅₅Al₃Y₂,which has a strong amorphous forming ability.The maximum amorphous critical dimension is 1 mm.The initial precipitation driving force of the crystal phase of the system was calculated.Seventy-five amorphous components were designed based on the driving force criterion.Their amorphous forming ability was evaluated by combining the amorphous empirical criteria.It was found that Zr₅₂Cu₃₁Al₁₅Y₂ and Zr₅₀Cu₃₀Al₁₅Y₅ have the strongest amorphous forming ability.The driving force surface of Zr-Cu-Al with Y content of 2%and 5%were constructed.The combination of experimental results and driving force surface proved that the amorphous forming ability has a good correspondence with the driving force.A range of components having a strong amorphous forming ability is predicted.