(Cu50Zr50)92Al8块体非晶合金高温塑性变形过程中的晶化行为

Crystallization Behavior of (Cu50Zr50)92Al8 Bulk Metallic Glass During the High Temperature Plastic Deformation

摘要:

采用水冷铜模吸铸法制备直径2 mm的 (Cu50Zr50)92Al8块体非晶合金。利用X射线衍射 (XRD)、差示扫描量热分析仪 (DSC) 对该非晶合金的结构及热力学参数进行表征。利用万能试验机在过冷液相区内对该非晶合金进行压缩变形，研究变形量 (20%，60%和80%) 对非晶合金显微结构和热稳定性的影响。结果表明，塑性变形使得该非晶合金的热稳定性降低，并导致其部分晶化，其晶化程度取决于合金的变形量的大小，当变形量为80%时，该合金的XRD图谱中出现了明显的晶化峰。晶化相的析出使得变形后的非晶合金的显微硬度有明显提高

Abstract:

The rod of the (Cu50Zr50)92Al8 (at%) bulk metallic glass(BMG) with a diameter of 2 mm was prepared by water-cooled copper mould sucking method, and its amorphous feature of the as-cast alloy was characterized by X-ray diffraction (XRD). The thermodynamic parameters of the bulk metallic glass were determined by differential scanning calorimeter (DSC). The alloy was compressed to different strains(20%, 60% and 80%) in the super-cooled liquid region, and the effects of the plastic strains on the microstructure and the thermal stability of the alloy were investigated. It is found that the deformation reduces the thermal stability of the alloy, and a partial crystallization occurs during the deformation in the alloy. The extent of the crystallization is strongly dependent on the deformation strain, and as the strain increases to 80%, the peaks of the crystallites can be clearly observed on the XRD pattern of the alloy. The present of the crystallites increase the mico-hardness of the alloy