ZrC粒子を含むZr_55Al_10Ni_5Cu_30バルク金属ガラス複合材料のナノ結晶化挙動

Abstract

Zr_55Al_10Ni_5Cu_30 bulk metallic glass composite containing 10 vol% crystalline ZrC particles was prepared by an in-situ reaction between Zr-based melt and graphite powder being followed by an injection casting into a copper mould. The crystallization process of the composites during annealing at 723K has been investigated by using DSC, X-ray diffraction, TEM and hardness test. It is found that an unknown crystalline phase appears at first along the interface between ZrC particle and the matrix of the composite, and then a homogeneous nanocrystallization occurs in the matrix. The nanocrystalline phase precipitated in the matrix has a higher hardness than the hardness of the amorphous phase which remained in the matrix. Hardness of the matrix increases with increasing the volume fraction of the nanocrystalline phases. After annealed at 723K for 40min, most of the matrix has been transformed into crystalline phases with a final average grain size of about 120nm.