1、465Vol.46No.520105581588ACTA METALLURGICA SINICA May. 2010pp.581588 7050(,110016705067%, 120,4hT612.6%.,.32hT6.T6,.1204h,165, , , 1656hT76.1351801h,.7050,TG146.2A0412 1961(201005 0581 08INVESTIGATION OF POSTCOLD ROLLING AGING PRO-CESSES ON SOLUTIONIZED 7050ALUMINUM ALLOYWANG Dong, MA ZongyiShenyang

2、National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences,Shenyang 110016Correspondent:MA Zongyi, professor, Tel:(02483978908, E-mail:zymaSupported by National Basic Research Program of China (No.2005CB623708Manuscript received 20091102, in revised form 2010

3、0224ABSTRACT 7050aluminum alloy samples were subjected to 67%cold rolling (CRdeformation after solution treatment, and then were aged at 120. The dislocations introduced by the CR increasedthe strength of the samples. The strength of the sample aged at 120for 4h (CR4increased by 12.6%compared to tha

4、t of T6sample. The strength of the 7050samples decreased with increasing the aging time due to the coarsening of heterogeneouslynucleated precipitates. However, the strength ofthe sample aged at 120for 32h is still higher than that of the T6sample. Furthermore, the size and particle interval of the

5、grain boundary precipitates increased as the aging time increased. The CR4sample was aged at 165for dierent times. The strength of the samples decreased with increasing the aging time due to the annihilation of dislocations and the growth of the precipitates. The strength of the sample aged at 165fo

6、r 6h is similar to that of T76sample. In the CR4sample aged at135180for 1h, the number of dislocations reduced and the size of precipitates increased with increasing the temperature, which results in a decrease in the strength of the samples.KEY WORDS 7050aluminum alloy, cold rolling, aging process,

7、 mechanical property, microstructureAlZnMgCu,1.1943*2005CB623708:20091102,:20100224:, 1980,DOI:10.3724/SP.J.1037.2009.007237075,2, 3.Zn, MgCu,FeSi ,Zn/Mg(ZrSc,7000.7000.,. 7000,4 7. 7000.58246: GP (MgZn2, , GP , , 8. 7000, . T6, , ,. Mg ,(PFZ.PFZ , , 7, 9. , , T7×, . , . 10%15%., , PFZ ., ,5, 1

8、0. , ,., 700011,1%5%. 9, 12, , . 13, 14, , , . Wang Ma 107050. , , ., 7000, 700015 17. ,. Lin 157A0450%. , , . Wang 17. , T6, ,. , , , ,. , T6,17.7050ALCOA, ., 1.7050,.17050(, %:Zn 6.18, Mg 2.20, Cu 2.21, Zr 0.13, Si 0.11, Fe 0.10, Al . 20mm , 470 48h, , 4306mm. 4701h, ,1h 2mm(67%. 1204, 12, 2432h,

9、CR4, CR12, CR24CR32. , CR4165 124h, 135, 1501801h. , T6(12024h T76(1206h+16516h , T6T76. 1. ZEISS Axiovert 200MAT (OM , , 0.5mL HF+15.5mL HNO 3+84mL H 2O+3g CrO 3. (TEM, TEM, 30%+70% 35 , 19V. Instron 5848, 3, , 5mm, 1.5mm, 1mm. Quanta 600(SEM.17050Table 1Aging treatment of 7050Al alloy quenched at

10、470 for 1hSample Heat treatmentT6120/24hT76120/6h+165/16hCR4Cold rolling (67%+120/4hCR12Cold rolling (67%+120/12hCR24Cold rolling (67%+120/24hCR32Cold rolling (67%+120/32h22.170501a T6. , . T6. 1b CR4 . , 30 40 , 16, 185:7050583.24h (1c, CR24,CR4., 120.,., ,.,120,. 17050Fig.1Optical microstructures

11、of 7050plates rolled at430from 20mm to 6mm and then treated with various conditions(aT6, partial recrystallization occured (bCR4, more shear bands appeared (cCR24, shear bands decreased2aT6TEM .,8.CR4(2b1204h, ,.,T6,T6., .,;, .CR24,(2c, 120.CR4, CR24,.3aT67050TEM27050TEMFig.2TEM micrographs of preci

12、pitates and disloca-tions within grains of 7050plates treated by T6(a,CR4(band CR24(c58446. ,(PFZ, 19. T6, CR4, (3b. CR41204h, T6, ., ., . , , . , 4h T6. , PFZ T6, . CR24T6 37050TEM Fig.3TEM micrographs of grain boundary precipitates and precipitatefree zones along boundary of 7050 plates treated by

13、 T6(a,CR4(band CR24(c, , , . , , , PFZ(3c.47050. CR4 681MPa, T612.6%. ,. , , 120, ., . , CR4 4h, T6. , 7050 120 ,GP ., , GP , 17. , , , , (2c, ,.5a CR4. , , ., . 32h 4h (5b. 2, , . , , , . , 3, PFZ , , PFZ . ,5. ,.2.270506a 1650.5h 24h . 0.5h ,618MPa, CR4. , 47050Fig.4Tensile properties of 7050plate

14、s with various treat-ments5:7050585. 6h ,498MPa, T76(4. 24h , 426MPa. 10h . 6b 135, 150, 1651801h . 1351h , 663MPa, CR4. , . 180 1h T76., 1801h.7a CR41651h . CR4(1b , , . 1656h ,(7b. 15,., , ,(1b. 165, , ,. , .TEM , 1651h , (8a, CR4 , 165, . , , CR4(2b. , 1651h CR4. 6h (8b, , . CR4(2b, 165, . , 6 h

15、5CR4CR327050Fig.5SEM micrographs showing fracture surfaces of the 7050samples treated by CR4(aand CR32 (b6CR4Fig.6Eect of duplex aging on tensile properties of the CR4treated 7050plate(aduplex aging at 165for various times(bduplex aging at various temperatures for 1h 586 É, É Ý&#

16、201; Ô T76 6 h Ó ² ¯ Æ 46 ¥ 1 h Ô Â Ô (Ä 8d. Ì 165 ¦ Ö µ ¡ Æ, , Ö Ô ÄÉ T76 , Í Ô T76 Ô½. Ä 8c Î 180 ¦ÞÅ 1 h TEM . Ö ÆÉ´

17、À. Â Ô ­, ÔÌ Õ É  Æ , Ô Ä ß 165 ¦ 6 h . Ô 165 ¦ 6 h Ô½. CR4 Ì 165 ¦ 1 h , Ô½ Æ ·Ù , ÝÑ Ô ¿ (Ä 9a, Â É CR4 (Ä 3b. ½ 6 h, Ý

18、9; ÔÙ¶ (Ä 9b. Î Ô ­ 180 ¦ , 1h ¬ § ª ¡ ÝÑ Ô Ä (Ä 9c É 165 ¦ 1 h , ß 165 ¦ 6 h . ¬ , ÞÅ Ô ° Ô Ö É. Ä 10 Î ÂÞÅ ©Ø¯

19、66; . ÞÅ ©Ø¯ ¶Å   (Ä 5, Ø ¯ É´ Ú Âº» ¿, Ú©Ø» . Ä 8 ½ 9 ¬ , ßÞÅ , ÝɽÝÑ Ô ¨Â , © , Æ Ç À´

20、 Ô. Â Ô Í, ÝɽÝÑ Ô Ä¸¤Û Ö Ô¡ Ô٠ͨ ß. © ¦ , È, Ü ¦±Ô٠ΨÈ, ºÆ ©Ø» د 5,20 . § 7 CR4 165 1 6h Fi

21、g.7 Optical microstructures of the CR4 treated 7050 plates with duplex aging at 165 Ë ¥ÝÄ ¼ ÕÓ ¦ ¤ for 1 h (a and 6 h (b 8 CR4 Fig.8 TEM micrographs of precipitates within grains of CR4 treated plates with 165 (b and 180 /1 h (c, and T76 treated plate (d

22、Á Á T76 ÜÈ Ó¥ ¤ ¤/1 h (a, 165 ¤/6 h 5 È Ð : Þ ¤ 7050 ¾Ô ¹ 587   9 CR4 Fig.9 TEM micrographs showing grain boundary precipitates of the CR4 plates with various treatments (b 165 /6 h (c 180 /1 h (a 165 /1 h ¤ &#

23、193; ¤ ÜÐ Ó¥ ¤ 10 CR4 Fig.10 Fractographs of CR4 treated plates with various treatments (b 165 /6 h (c 180 /1 h (a 165 /1 h ¤ ÝÄ ¤ ×Æ¥ ¤  588 3 ¦ 67% , Ì 120 ¦¶Å , Öµ É´ Æ

24、2;Ù ¡ÝÉ Ô , Í ÔÛ ½É. ÝÑ Ô T6 Ô ¡ Ρ£, ÍÛ . (2 ¦ 67% Ì 120 ¦ 4 h , Ô T6 ­ 12.6%. Í, © ÔÛ , Í 32 h ÔÜ­ (1 T6 (3 165 180 ¶ Ó

25、0;² ¯ Æ ÊÝ ¼ § É °¸Ï¯ 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 46 ¥ ¦ 6h ¦ÞÅ 1 h , ©  . 4h , ß 165 ¦ÞÅ (4 Ì 120 ¦ , Í, Öµ¿ ÆÉ´

26、; À, ÝÉ¢ÝÑ Ô¨Û É. Ì 135180 ¦ÞÅ 1 h, Ö Æ Ô Ô ­Ü ß, ÜÝÉ¢ ÝÑ Ô Ä Ô ­Ü É. Ì 120 ¦ Í, . 4h ¦ÞÅ ÔÛ ,

27、Ü © Û ­, Ô T76 Ô½. ß 135 , Ô ­, ÔÛ , 165 ¬ º 1 Hatch J E. Aluminum Properties and Physical Metallurgy, Metals Park, Ohio: American Society for Metals, 1984: 1 2 Wagner J A, Shenoy R N. Metall Trans, 1991; 22A: 2809 3 Dai X Y, Xia C Q, Wu A R, Wang J W, Li Y Y. Mater Rev, 2006; 20: 104 , , , , . , 2006; 20: ( 104 Starink M J, Wang S C. Acta Mater, 2003; 51: 5131 Dumont D, Deschamps A, Brechet Y. Mater Sci Eng, 2003; A356: 326 Kamp N, Sinclair I, Starink M J.