Nb segregation at prior austenite grain boundaries and defects in high strength low alloy steel during cooling

Publication date: 5 February 2017
Source:Materials & Design, Volume 115
Author(s): Xianglong Li, Ping Wu, Ruijie Yang, Shoutian Zhao, Shiping Zhang, Sen Chen, Xingzhong Cao, Xuemin Wang
The segregation of Nb at prior austenite grain boundary during cooling was investigated. Auger electron spectroscopy and electron backscattering diffraction were performed to characterize the segregation of Nb, while positron annihilation lifetime spectroscopy was applied to analyze the behavior of defects within the material. The formation energy of vacancy and the activation energy of the climb or glide of dislocations coincide well with reported results. The segregation of Nb at the grain boundaries increases with the decreasing defects during the cooling process. The diffusion of vacancy and the climb or glide of dislocations may both contribute to the segregation of Nb.

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