Cu基块状非晶合金微观结构的特点及组织演化

采用水冷铜坩埚-铜模吸铸法成功制备了底部直径10 mm、长度80 mm的Cu50Zr42Al8圆锥形块体非晶试样.利用X射线衍射,光学显微镜和SEM、TEM等测试手段对圆锥形试样轴向和径向微观结构的特点和微观组织的演变进行了研究.结果表明,由于冷却速率的不同,圆锥形试样的显微组织由表面非晶区、中心等轴晶区及介于两区之间的过渡区组成.过渡区由非晶和晶体相组成,晶体的尺寸和体积分数由表面向中心逐渐增加,具有梯度变化的特征.

Characteristics and evolution of microstructure in Cu-based bulk amorphous alloys

Bulk Cu_(50)Zr_(42)Al_(8) coniform amorphous samples(10 mm in bottom diameter and 80 mm in length) were successfully prepared with water-cooled copper crucible and cooper mold suck cast.Using the techniques of X-ray diffraction,optical microscope,SEM,and TEM,the experimental investigation of axial and radial characteristics and evolution of microstructure were conducted.Results indicated that with gradual change of cooling rate,the micro-structure of coniform samples was composed of three portions,namely the amorphous external zone,central crystal zone,and transition zone in-between.The transition zone was composed of amorphous structure and crystal;and the crystal size and volume fraction increased gradually inward from the surface.