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主要研究大晶粒退火态纯锆在液氮温度下均匀轧制时的形变组织特征及孪生机制。利用光学显微镜、扫描电镜、电子背散射衍衬(EBSD)、X射线衍射等对不同变形量样品的变形组织和织构进行了研究,重点结合软件对EBSD结果进行组织重构和机理分析。结果表明,液氮温度轧制时大晶粒纯锆中产生的孪晶类型为C1{11 2 2}<11 23>、T1{10 1 2}<10 1 1>和T2{11 2 1}<11 26>孪晶,其中C1{11 2 2}<11 23>孪晶最容易产生且为主要孪生类型。变形开始时,3种孪晶的数量迅速增多,而小角度晶界含量较少;变形量增大到30%时,小角度晶界含量占优势。变形初始阶段孪生优先于滑移进行,且孪生变形是最主要的变形方式,当变形量为30%时,孪晶协调的位错滑移成为主要的变形方式。变形过程中织构类型未发生变化,保持基面双峰织构(偏离ND方向±30°左右),但强度随着变形量的增大呈减小趋势。
The main study of large grain annealed pure zirconium at liquid nitrogen temperature uniformity during the deformation of the microstructure and twin mechanism. The deformation and texture of samples with different deformations were investigated by optical microscopy, scanning electron microscopy, electron backscatter diffraction (EBSD) and X-ray diffraction. The results of tissue remodeling and mechanism analysis of EBSD were combined with software. The results show that the type of twins generated in large grain pure zirconium during liquid nitrogen rolling is C1 {11 2 2} <11 23>, T1 {10 12} <10 1 1> and T2 {11 2 1} <11 26> twins, where the C1 {11 2 2} <11 23> twins are the most easily generated and predominately twinned. At the beginning of deformation, the number of three kinds of twins increased rapidly, while the content of small-angle grain boundaries was less. When the amount of deformation increased to 30%, the content of small-angle grain boundaries dominates. The twins take precedence over slippage in the initial stages of deformation, and twin deformation is the most important deformation mode. When the deformation amount is 30%, twin-coordinated dislocation slip becomes the main deformation mode. The texture type did not change during deformation, and the bimodal texture of the basal plane was maintained (± 30 ° from the ND direction), but the intensity tended to decrease with the increase of deformation.