摘要
Effect of large cold deformation on the age-hardening characteristics of 2024 aluminum alloys was investigated. The results reveal: 1) the aging response is accelerated after large cold deformation, and the peak strength is attained after aging for 40 min; 2) double aging peaks can be found in the age-hardening curves, and the first peak appears when aged for 40 min. The corresponding peak tensile strength (sb) and elongation are up to 580 MPa and 9.2% respectively, the second peak appears when aged for 120 min, but the peak tensile strength(520 MPa) is lower than the first one; 3) in early stage of aging (<40 min), elongation slightly increases from 8% with prolonging aging time of the alloy. Elongation markedly decreases to 2% after aging for 60 min, and shows a plateau with the prolonging of aging time on the age-elongation curve. It is indicated that the high density of dislocation introduced by large deformation accelerates the precipitation of GP zones and the aging response of the alloy. The first aging peak is due to the formation of GP zones and the deformation strengthening caused by the high density of dislocation. And the second peak present in the aging curve is attributed to the nucleation and growth of S’ phase. The offset between dislocation density decreases and precipitation S’-phase finally results in the phenomenon of double aging peaks when aged at 190 ℃. Moreover, it is suggested that the formation of PFZ and coarse equilibrium phase accompanied by the precipitation of S’ phase decrease the elongation.
Effect of large cold deformation on the age-hardening characteristics of 2024 aluminum alloys was investigated. The results reveal： 1） the aging response is accelerated after large cold deformation, and the peak strength is attained after aging for 40 rain; 2） double aging peaks can be found in the age-hardening curves, and the first peak appears when aged for 40 min. The corresponding peak tensile strength （σb） and elongation are up to 580 MPa and 9.2% respectively, the second peak appears when aged for 120 min, but the peak tensile strength （520 MPa） is lower than the first one; 3） in early stage of aging （〈40 min）, elongation slightly increases from 8% with prolonging aging time of the alloy. Elongation markedly decreases to 2% after aging for 60 rain, and shows a plateau with the prolonging of aging time on the age-elongation curve. It is indicated that the high density of dislocation introduced by large deformation accelerates the precipitation of GP zones and the aging response of the alloy. The first aging peak is due to the formation of GP zones and the deformation strengthening caused by the high density of dislocation. And the second peak present in the aging curve is attributed to the nucleation and growth of S＇ phase. The offset between dislocation density decreases and precipitation S＇-phase finally results in the phenomenon of double aging peaks when aged at 190 ℃ Moreover, it is suggested that the formation of PFZ and coarse equilibrium phase accompanied by the precipitation of S＇ phase decrease the elongation.
出处
《中国有色金属学会会刊：英文版》
EI
CSCD
2006年第5期1121-1128,共8页
Transactions of Nonferrous Metals Society of China
基金
Project(50571069) supported by the National Natural Science Foundation of China
Project(05A061) supported by the Department of Education of Hunan Province, China
关键词
铝合金
冷变形
时效强化
机械性能
aluminum alloy
cold deformation
aging strengthening
mechanical properties
