锌铝基Al_2O_3复合层激光重熔区内陶瓷相结构的分析

An Analysis of Microstructures for Al_2O_3 in Laser-remelted Area on ZnAl - based Alloy

用透射电子显微镜,并结合光学显微镜、扫描电子显微镜、俄歇电子能谱仪、X射线衍射等技术对锌铝基Al_2O_3陶瓷复合层激光重熔区的组织进行了分析。结果表明:表面涂覆Al_2O_3的锌铝合金经过激光处理后,在激光扫描的轨迹上形成近似半圆形的重熔区。其晶粒由表层到内层明显增大。根据晶粒尺寸清楚地分为三个区域,分别是位于表面层的细晶区,基体区,细晶区与基体区之间的过渡区;对激光重熔区中过渡区进行的透射电子显微镜分析表明Al_2O_3陶瓷相为体心四方结构,即δ-Al_2O_3相。其点阵常数为a_0=7.943×10^(-8)cm,c_0=23.500×10^(-8)cm。

A study of the microstructures for the Al2O3 ceramic thin film in the laser -remelted area on a ZnAl - based alloy was performed by means of a transmission electron microscope associated with the techniques of optical microscope, scanning electron microscope, Auger electron spectroscope, and X ray diffraction. It is shown that the grain size increases from the surface to the matrix of the laser - remelted area, which may be divided into three zone according to the sizes of the grains; a fine grain zone at the surface layer, a matrix zone, and an intermediate zone between the fine grain zone and the matrix zone. The Al2O3 ceramic phase in the intermediate zone was a body -centered tetragonal system, i. e. 8 - Al2O3 and its crystal constants were: a0 =7.943×10-8cm, c0 =23.500×10-8cm.