DESIGN AND PREPARATION OF IN SITU Pb-RICH PARTICLES/Al BASE METALLIC GLASS MATRIX COMPOSITE

The typical Al-Pb immiscible alloy and the additional elements Ni,Y and Co were selected,and a new Al_(82.87)Pb_(2.5)Ni_(4.88)Y_(7.8)Co_(1.95) multicomponent immiscible alloy has been designed. The ribbon samples of the multicomponent alloys were prepared by rapidly quenched method.The microstructure characterization,thermal stability and formation of composite microstructure have been investigated.The results indicate that the single-phase alloy melt separates into AlNiYCo-rich and Pb-rich liquids during cooling through the miscibility gap.Subsequently,the separated AlNiYCo-rich and Pb-rich liquids solidify into Al-based glassy matrix and crystalline Pb-rich phase,respectively. The crystalline Pb-rich phase in form of spheres is homogeneously embedded into the Al-based metallic glass matrix.Based on the mechanism of the liquid-liquid phase transformation in the miscibility gap of the multicomponent immiscible alloy,a new method has been developed to produce in situ crystalline spheres embedded into the metallic glass matrix by rapid solidification.