Acta Metall Sin  2019, Vol. 55 Issue (4): 547-554    DOI: 10.11900/0412.1961.2018.00414
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Evolution of Microstructure and Texture During Cold Deformation of Hot-Extruded GH3625 Alloy
Yubi GAO1,Yutian DING1(),Jianjun CHEN1,Jiayu XU1,Yuanjun MA1,Dong ZHANG2
1. State Key Laboratory of Advanced and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China
2. State Key Laboratory of Nickel and Cobalt Resources Comprehensive Utilization, Jinchuan Group Ltd., Jinchang 737100, China
Abstract

GH3625 alloy is a wrought nickel-based superalloy mainly used in aeronautical, aerospace, chemical, nuclear, petrochemical and marine applications industry due to its good combination of mechanical properties and corrosion resistance on prolonged high-temperature exposure to aggressive environments. However, the cold deformation microstructure directly determines the microstructure of the alloy pipe, thereby affecting the performance of the alloy pipe. In this work, the microstructure evolution, grain boundary characteristics distribution, dislocation density, stress distribution and texture evolution of the hot-extruded GH3625 superalloy during cold deformation were investigated by EBSD technique. The results show that the degree of grain deformation increases and the grain morphology changes from flat to thin strip, with the increase of cold deformation. The rotation of the crystal makes the grain boundary perpendicular to the loading pressure axis. With the increase of cold deformation, the high angle grain boundaries (HAGBs) gradually changes to the low angle grain boundaries (LAGBs), and the proportion of twin grain boundary increases gradually. The average of local misorientation ($θˉL$) increases with the increase of cold deformation, which can reflect the increase of dislocation density. With the increase of cold deformation, the uniformity of grain deformation gradually becomes better, and the stress concentration distribution gradually changes to the stress uniform distribution. With the cold deformation increases, the type of deformation texture remains basically unchanged, while the strength of the Copper texture {112}<111> with stable orientation is slightly reduced. Meanwhile, the Rotated-cube texture {001}<110> generated by inhomogeneous plastic deformation is reduced in strength. In addition, the formation of deformation twin results in a decrease in the strength of the Goss texture {110}<001> and the Brass-R texture {111}<112>.

 ZTFLH: TG146.15
Fund: National Key Research and Development Program of China(No.2017YFA0700703);National Natural Science Foundation of China(No.51661019);Program for Major Projects of Science and Technology in Gansu Province(No.145RTSA004);Program for State Key Laboratory of Nickel and Cobalt Resources Comprehensive Utilization(No.301170503)
Corresponding Authors:  Yutian DING     E-mail:  dingyt@lut.edu.cn