孪晶片层结构在室温轧制过程中的微观结构演变

研究了一种具有纳米孪晶片层结构的电解沉积铜的微观结构特征及其在室温轧制形变后的微观结构演变.结果表明,电解沉积制备的纯铜样品由柱状晶组成,柱状品内含有平行于样品沉积表面的纳米量级厚度的高密度孪晶片层结构,在孪晶界上缺陷很少,为共格孪晶界.形变后,孪晶片层的微观结构特征与片层厚度密切相关.粗大的孪品片层的形变行为以全位错运动为主,而细小的孪晶片层的形变行为以肖克莱(Shockley)位错在孪晶界上的滑移为主,从而导致几个纳米厚的超细孪晶片层消失.

Microstructure evolution of twin lamellae with different lamellar size in rolling deformation at room temperature

Microstructural feature of an electrodeposited nanostructured Cu plate and those after rolling at room temperature are characterized by means of transmission electron microscopy (TEM) and high resolution electron microscopy (HRTEM).The results show that the as-deposited Cu samples consist of columnar grains.Each columnar grain contains a high density of lamellar twins with spacings on the nanometer scale.The twin boundaries are coherent and approximately perpendicular to the growth direction of the Cu plate.The structural features of the as-rolled samples are obviously related to the spacing between the lamellar twins.Perfect dislocations are active in the coarse lamellae,however,Shockley partial dislocations appeared along the coherent twin boundaries in the fine twin lamellae,and the accumulation of which leads to the disappearance of the ultra-fine lamellae.