Structures and mechanical properties of ECAP processed 7075 AI alloy upon natural aging and T651 treatment.

Conference · Thu Jan 01 04:00:00 EST 2004

OSTI ID:977542

Zhao, Y ^[1]; Liao, Xiaozhou; Valiev, R Z ^[2]; Zhu, Y T ^[3]

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1. Yonghao
2. Ruslan Zufarovich
3. Yuntian Theodore

Equal-channel angular pressing (ECAP) processed ultrafine grained (UFG) and coarse grained (CG) 7075 Al alloys were treated by natural aging and T651 temper (annealed at 120 C for 48 h in Ar atmosphere), respectively. Mechanical tests showed that for the UFG sample, the natural aging resulted in the highest strength (the ultimate tensile strength is 720 MPa). In contrast, for the CG sample, the T651 treatment resulted in the higher strength (the ultimate strength is 590 MPa) than the natural aging (530 MPa). Microstructural analyses indicated that the enhanced strength of the T651 treated CG sample was mainly caused by high densities of G-P zones and metastable {eta}{prime} precipitate. The enhanced strength of the naturally aged UFG sample was mainly caused by the high densities of G-P zones and dislocations. Upon T65 1 treatment, the dislocation density of the UFG sample deceased significantly, overcompensating the precipitation strengthening.

• Research Organization: Los Alamos National Laboratory
• Sponsoring Organization: DOE
• OSTI ID: 977542
• Report Number(s): LA-UR-04-2432
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGING
ALLOYS
DISLOCATIONS
MECHANICAL PROPERTIES
MECHANICAL TESTS
PRECIPITATION
PRESSING
TENSILE PROPERTIES
ULTIMATE STRENGTH