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Mechanical Properties and Microstructures of Commercial‐Purity Aluminum Processed by Rotational Accelerated Shot Peening Plus Cold Rolling
Author(s) -
Liu Yanfang,
Cao Yang,
Zhou Hao,
Chen Xuefei,
Liu Ying,
Xiao Lirong,
Huan Xiaowei,
Zhao Yonghao,
Zhu Yuntian
Publication year - 2020
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201900478
Subject(s) - materials science , metallurgy , shot peening , microstructure , ductility (earth science) , aluminium , surface roughness , equiaxed crystals , grain size , composite material , residual stress , creep
Commercial‐purity aluminum with 99.7% purity is processed by rotational accelerated shot peening (RASP) and cold‐rolling. RASP samples are rolled at room temperature to a thickness reduction of 20% and 30%, for the purpose of surface roughness reduction and strengthening. Detailed microstructural characterization and hardness tests reveal that cold‐rolling cause grain growth at the surfaces of RASP samples from ≈472 to ≈1000 nm. Moderate cold‐rolling is effective in smoothing the surface of RASP samples, while improving strength and maintaining ductility. However, cold‐rolling to more than 30% thickness reduction eventually diminishes the gradient nanostructure. During cold‐rolling of RASP samples, a transition zone with strong strain incompatibility is noticed by a sharp rise in hardness at some point of the hardness‐distribution curve from the surface to the core of the sample. This transition zone is a result of quick generation of geometrically necessary dislocations. Although the transition zone with strong strain incompatibility is short‐lived, it is anticipated to be common among gradient‐nanostructured materials under cold‐rolling condition.