Homogeneity of ultrafine-grained copper deformed by high-pressure torsion characterized by positron annihilation and microhardness

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• 作者：J. Č ; í ; ž ; ek^a ; ^{jakub.cizek@mff.cuni.cz"" rel=""nofollow} ; O. Melikhova^a ; M. Janeč ; ek^a ; O. Srba^a ; Z. Barnovská ; ^a ; I. Prochá ; zka^a ; S. Dobatkin^b
• 关键词：Severe plastic deformation ; High-pressure torsion ; Lattice defects ; Vacancies ; Positron annihilation
• 刊名：Scripta Materialia
• 出版年：2011
• 出版时间：July 2011
• 年：2011
• 卷：65
• 期：2
• 页码：171-174
• 全文大小：382 K

文摘

Spatially resolved positron annihilation was employed for mapping lateral defect distribution in Cu deformed by high-pressure torsion. Parameters describing Doppler broadening of the annihilation peak were used for mapping the spatial distribution of defects. In comparison with microhardness showing a clear development towards homogeneity, positron annihilation revealed that spatial distribution of defects was far from uniform, even after 25 turns. This was mainly due to a higher concentration of deformation-induced vacancies at the periphery compared with the center.