Low-Temperature Creep at Ultra-Low Strain Rates in Pure Aluminum Studied by a Helicoid Spring Specimen Technique

• Shen Junjie

  Department of Molecular and Materials Science, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University

• Yamasaki Shigeto

  Department of Molecular and Materials Science, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University

• Ikeda Ken-ichi

  Department of Electrical and Materials Science, Faculty of Engineering Sciences, Kyushu University

• Hata Satoshi

  Department of Electrical and Materials Science, Faculty of Engineering Sciences, Kyushu University

• Nakashima Hideharu

  Department of Electrical and Materials Science, Faculty of Engineering Sciences, Kyushu University

抄録

The creep behavior in pure aluminum has been investigated by helicoid spring creep tests at strain rates, \\dotε, lower than 10⁻¹⁰ s⁻¹ and low temperature ranging from 0.32T_m to 0.43T_m. It was found that the creep behavior in this region depends strongly on grain sizes and impurity concentrations. For high-purity aluminum (5 N Al) with an average grain size, d_g>1600 μm, nearly the wire diameter of the spring sample, where the role of grain boundary during creep deformation can be negligible, the stress exponent was n∼5 and the activation energy was Q_c=32 kJ/mol. Microstructural observation showed the formation of large dislocation cells (∼10 μm) and tangled dislocations at the cell walls. For high-purity aluminum (5 N Al) with d_g=24 μm, the stress exponent was n∼1 and the activation energy was Q_c=15 kJ/mol. On the other hand, for commercial low-purity aluminum (2 N Al) with d_g=25 μm, the stress exponent was n=2 and the activation energy was Q_c=25 kJ/mol. Microstructural observations revealed dislocations emitted from grain boundaries, those dislocations interacting with intragranular dislocations and the formation of dislocation cells in the grains. Based on those experimental results, the low-temperature creep mechanisms in pure aluminum at \\dotε<10⁻¹⁰ s⁻¹ have been discussed.

収録刊行物

• MATERIALS TRANSACTIONS

  MATERIALS TRANSACTIONS 52 (7), 1381-1387, 2011

  公益社団法人 日本金属学会

キーワード

• pure aluminum
• dislocation
• ultra-low strain rate
• helicoid spring creep test
• grain boundary
• stress exponent

詳細情報

• CRID: 1390282679228684800
• NII論文ID: 10029296840
• NII書誌ID: AA1151294X
• DOI: 10.2320/matertrans.m2010405
• COI: 1:CAS:528:DC%2BC3MXhtFWqtr%2FE
• ISSN: 13475320
• ISSN: 13459678
• HANDLE: 2115/75556
• NDL書誌ID: 11135862
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I11135862
• Web Site: https://www.jstage.jst.go.jp/article/matertrans/52/7/52_M2010405/_pdf
• 本文言語コード: en
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