高温轧制 Zr-4 合金板织构的形成机制

Mechanism of Texture Formation of Zircaloy 4Plate Rolled at High Temperature

采用Ｘ射线衍射、金相和电子显微等方法对９４０℃轧制量６９％的Ｚｒ４合金板的织构进行了研究。结果表明，从试样表层到中间层形成了不同类型的织构，由基极主要取向轧面法向的织构逐渐转化为基极主要取向横向的织构，即ｆｎ值逐渐减小，ｆｔ值逐渐增大；试样中间层形成了集中的（１２１０）［１０１０］织构，ｆｔ＞０．４５。金相和电子显微镜观察表明，这种织构的变化是由轧制过程中试样沿其厚度方向的温度梯度造成的；由于适合的高温和有利的轧制应力，使得应力诱发马氏体相变过程导致了试样中间层（１２１０）［１０１０］织构的形成，这是高温轧制得到强ｆｔ织构的原因。

The textures of Zircaloy 4 plate rolled at 940℃ have been investigated by means of X ray diffraction,optical microscopy(OM)and transmission electron microscopy(TEM).The results indicate that different type textures are developed in different layers along the thickness of the specimen.The texture of basal poles mainly oriented in the normal direction in the surface layer evolves into one of that mainly oriented in the transverse direction in the central layer,Very strong(1210)is developed in the central layer and ft of this layer is greater than 0.45.The examination of OM and TEM have revealed that the distribution of temperature gradient along the thickness of the specimen during rolling give rise to the orientation variation of basal poles in different layers.Stress induced martensitic transformation occurs in the central layer because of the proper high temperature and favorable rolling stress and it brings about very strong(1210)texture formed as well as ft increased in this layer.