1 AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China 2 School of Materials Science and Engineering, Harbing Institute of Technology, Harbin 150001, China
The microstructure and ageing precipitation behavior of ZL205A alloy with different addition of Sc were investigated by OM, SEM and TEM. The results show that the grain refinement effect of Sc (up to 0.12%, mass fraction, the same below) is not observed in ZL205A alloy; the residual particle W (AlCuSc) phase is formed after heat treatment when the Sc content is 0.06%, and transformed to strip-liked structure with the increase of Sc content in the grain interface; the dispersed phases Al3 (Zrx, Ti1-x) in ZL205A alloy are transformed to Al3 (Zrx, Tiy, Sc1-x-y), and the number of the dispersed phases increase with the increase of Sc content; when the Sc content is 0.06%, the ageing response, peak hardness increase slightly, and the yield strength increases by 4%; while the Sc content increases to 0.12%, the decrease of the solute concentration may reduce the number of the θ' phase due to the strip-liked W phase formed in the grain interface, which results in the dramatic decrease of the ageing response, peak hardness and mechanical properties; traces of Sc help to slow down the growth of θ' phase during the over-aged stage.
YANG G Y , JIE W Q , ZHANG R Q , et al. Behavior of microstructure evolution of ZL205A cast aluminum alloy during semi-solid isothermal annealing process[J]. Rare Metal Materials and Engineering, 2007, 36 (10): 1717- 1721.
doi: 10.3321/j.issn:1002-185x.2007.10.005
YU G L , ZHAO X . The casting process of large closed annular castings made of high strength Al-Cu alloy[J]. Journal of Materials Engineering, 2000, (9): 42- 43.
doi: 10.3969/j.issn.1001-4381.2000.09.013
LI M , WANG H W , ZHU Z J , et al. Effects of scraps and yttrium on the as-casting microstructure, hot tearing and solidification characteristics of ZL205A alloy[J]. Rare Metal Materials and Engineering, 2010, 39 (Suppl 1): 5- 10.
4
YAO D M , ZHAO W G , ZHAO H L , et al. High creep resistance behavior of the casting Al-Cu alloy modified by La[J]. Scripta Materialia, 2009, 61 (12): 1153- 1155.
doi: 10.1016/j.scriptamat.2009.09.007
5
LAMIKHOV L K , SAMSONOV G V . Modification of aluminum by transition metals[J]. Soviet Physics Doklady, 1964, 9 (2): 1- 8.
6
ELAGIN V I , ZAKHAROV V V , ROSTOVA T D . Some features of decomposition for the solid solution of scandium in aluminum[J]. Metal Science and Heat Treatment, 1983, 25 (7): 546- 549.
doi: 10.1007/BF00741946
7
TORMA T , KOVÁCS-CSETÉNYI E , TURMEZEY T , et al. Hardening mechanisms in Al-Sc alloys[J]. Journal of Materials Science, 1989, 24 (11): 3924- 3927.
doi: 10.1007/BF01168955
8
DRITS M E , BYKOV Y G , TOROPOVA L S . Effect of ScAl3 phase dispersity on hardening of Al-6.3%Mg-0.21%Sc alloy[J]. Metal Science and Heat Treatment, 1985, 27 (4): 309- 312.
doi: 10.1007/BF00652102
9
NORMAN A F , HYDE K , COSTELLO F , et al. Examination of the effect of Sc on 2000 and 7000 series aluminium alloy castings:for improvements in fusion welding[J]. Materials Science and Engineering:A, 2003, 354 (1/2): 188- 198.
10
EMADI D , RAO A K P , MAHFOUD M . Influence of scandium on the microstructure and mechanical properties of A319 alloy[J]. Materials Science and Engineering:A, 2010, 527 (23): 6123- 6132.
doi: 10.1016/j.msea.2010.06.042
11
NORMAN A F , PRANGNELL P B , McEWEN R S . The solidafication behavior of dilute aluminium-scandium alloys[J]. Acta Materials, 1998, 46 (16): 5715- 5732.
doi: 10.1016/S1359-6454(98)00257-2
12
CHEN Y C , FINE M E , WEERTMAN J R , et al. Coarsening behavior of Ll2 structured Al3(Zrx V1-x) precipitates in rapidly solidified Al-Zr-V alloy[J]. Scripta Metallurgica, 1987, 21 (7): 1003- 1008.
doi: 10.1016/0036-9748(87)90143-8
13
RYSET J , RYUM N . Scandium in aluminum alloys[J]. International Materials Reviews, 2005, 50 (1): 19- 44.
doi: 10.1179/174328005X14311
14
NOBLE B . Theta-prime precipitation in aluminium-copper-cadmium alloys[J]. Acta Materialia, 1968, 16 (3): 393- 401.
doi: 10.1016/0001-6160(68)90026-6
15
NUYTEN J B M . Quenched structures and precipitation in Al-Cu alloys with and without traceadditions of Cd[J]. Acta Metallurgica, 1967, 15 (11): 1765- 1770.
doi: 10.1016/0001-6160(67)90071-5
16
CHEN B A , PAN L , WANG R H , et al. Effect of solution treatment on precipitation behaviors and age hardening response of Al-Cu alloys with Sc addition[J]. Materials Science and Engineering:A, 2011, 530 (15): 607- 617.
17
KEITH E K , DUNAND C D , DAVID N S . Atom probe tomographic studies of precipitation in Al-0.1Zr-0.1Ti (at.%) alloys[J]. Microscopy and Microanalysis, 2007, 13 (6): 503- 516.
doi: 10.1017/S1431927607070882
18
TSUNEKAWA S , FINE M E . Lattice parameters of Al3(Zrx, Ti1-x) vs. x in Al-2at.% (Ti+Zr) alloys[J]. Scripta Metallurgica, 1982, 16 (4): 391- 392.
doi: 10.1016/0036-9748(82)90157-0
19
KNIPLING K E , KARNESKY R A , LEE C P , et al. Precipitation evolution in Al-0.1Sc, Al-0.1Zr and Al-0.1Sc-0.1Zr (at.%) alloys during isochronal aging[J]. Acta Materialia, 2010, 58 (15): 5184- 5195.
doi: 10.1016/j.actamat.2010.05.054
20
LIFSHITZ I M , SLYOZOV V V . The kinetics of precipitation from supersaturated solid solutions[J]. Journal of Physics and Chemistry of Solids, 1961, 19 (1/2): 35- 50.
21
IWAMURA S , MIURA Y . Loss in coherency and coarsening behavior of AlSc precipitates[J]. Acta Materialia, 2004, 52 (3): 591- 600.
doi: 10.1016/j.actamat.2003.09.042