Low Temperature Aging and Repeated Strain Aging in Ni Maraging Steels

• Takaki Setsuo

  Faculty of Engineering, Kyushu University

• Tokunaga Youichi

  Faculty of Engineering, Kyushu University

抄録

The hardening mechanism of Ni maraging steels on aging and on repeated strain aging has been investigated by means of specific heat, electrical resistivity and hardness measurements, etc. On aging in the temperature range from 600 to 800 K, Mo rich zones are formed prior to the precipitation of Ni₃Mo, leading to the pronounced hardening in Ni maraging steels. These zones are considered to transform to Ni₃Mo by the in situ type process in the later aging stage. At the aging temperature below 720 K, however, this transformation does not proceed in the hardening stage but occurs in the over aging stage.<BR>Repetition of low temperature aging and cold working (repeated strain aging) leads to the acceleration of formation of Mo rich zones, resulting in a rapid increase in tensile strength. For example, the tensile strength of a specimen with the 10 cycles repetition of the 748 K–120 s aging and 5% cold working reaches 1700 MPa, which exceeds the highest tensile strength of 1500 MPa attained by the 748 K–36 ks aging. This suggests that Mo rich zones are fromed on dislocations, and that the dislocations released (or newly generated) by the cold working on the above treatment can again supply the nucleation sites for the next formation of Mo rich zones.

収録刊行物

• Transactions of the Japan Institute of Metals

  Transactions of the Japan Institute of Metals 23 (1), 31-37, 1982

  社団法人 日本金属学会

キーワード

• General Engineering

詳細情報

• CRID: 1390001205117955456
• NII論文ID: 130003485939
• DOI: 10.2320/matertrans1960.23.31
• COI: 1:CAS:528:DyaL38XitVegtrs%3D
• ISSN: 24324701
• ISSN: 00214434
• Web Site: https://www.jstage.jst.go.jp/article/matertrans1960/23/1/23_1_31/_pdf
• 本文言語コード: en
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