【摘要】 用磁控溅射技术制备了Cu-Ta合金非晶薄膜,并采用扫描电子显微镜研究了压应力导致非晶薄膜表面形变和纳米晶化现象。结果表明:在纳米压头的作用下,非晶薄膜表面压痕的锯齿流边沿处形成了纳米级颗粒(纳米晶化)结构,且压痕外沿的颗粒尺寸大于内沿的颗粒尺寸。导致上述微观结构变化的主要原因可能是非晶自由体积流变膨胀过程中,压头的压应力使材料内部自由体积发生移动,在非晶基体中汇集成一些空位或气团,纳米晶粒在这些空位或气团处形核并长大;当气团积累到一定体积发生爆裂,导致屈服变形,纳米晶粒被挤到压痕锯齿流的前沿。更多还原

【Abstract】 The Cu-Ta amorphous films were prepared by magnetron sputtering.The deformation and nanocrystallization on the films induced by compressive stress from nanoindenter were studied by scanning electron microscopy(SEM).The results indicate that nanocrystallites are found to distribute along the edges of the serrated flow on the indents′ patterns and the grain size in the outer flow is bigger than that in the inner flow.It is proposed that the nanocrystallites are formed during the evolution of flow dilation of free volume in the amorphous phase. The compressive stress from the indenter moves the free volume to aggregate holes and air masses in the amorphous matrix.The nanocrystallites nucleate and grow behind these holes and air masses.When an air mass bursts and then yielding occur,the nanocrystallites are extruded to the frontier of the serrated flow.更多还原