Gradient nano–micro–structured surface layer was synthesized on Al–12.7Si alloy by means of surface mechanical attrition treatment. The microstructural evolution was examined by XRD and TEM. The surface intense deformation induced nanocrystallization mechanism was summarized as follows: upon the application of repeated loads, dislocation cells/sub–micro–grains form through slips, annihilations and recombinations of high density of dislocations in Al coarse grains. The misorientations between the dislocation cells/sub–micro–grains increased by cotinuously absorbing more dislocatons. High density of dislocations in sub–micro–grains developing in above route led to the redction of grain size and the increment of misorientatins between the refined grains, and finally equiaxed nc grains with random orientations formed. The refinement of Si particles was found to be carried out through single–or multi–slips of internal dislocations and partial dissolution, then the refined Si particles distributed niformly due to the plastic flows in Al matrix.
LIU Gang
,
YAN Wen-Cong
,
YU Fu-Xiao
,
DIAO Gang
,
DIAO Xiang
,
ZUO Liang
. NANOCRYSTALLIZATION OF Al–12.7Si ALLOY INDUCED BY SURFACE INTENSE PLASTIC DEFORMATION[J]. Acta Metall Sin, 2011
, 47(6)
: 649
-654
.
DOI: 10.3724/SP.J.1037.2011.00030
[1] Lu K, Lu J. Mater Sci Eng, 2004; A375–377: 38
[2] Wu X, Tao N, Hong Y, Xu B, Lu J, Lu K. Acta Mater, 2002; 50: 2075
[3] Wang K, Tao N R, Liu G, Lu J, Lu K. Acta Mater, 2006; 54: 5281
[4] Zhu K Y, Vassel A, Brisset F, Lu K, Lu J. Acta Mater, 2004; 52: 4101
[5] Sun Q, Shi Y N, Zhng X, Lu K. Acta Mater, 2007; 55: 975
[6] Wu X, Tao N, Hong Y, Liu G, Xu B, Lu J, Lu K. Acta Mater, 2005; 53: 681
[7] Tao N R, Wang Z B, Tong W P, Sui M L, Lu J, Lu K. Acta Mater, 2002; 50: 4603
[8] Zhang H W, Hei Z K, Liu G, Lu J, Lu K. Acta Mater, 2003; 51: 1871
[9] L¨u A Q, Liu G, Liu C M. Acta Metall Sin, 2004; 40: 943
(吕爱强, 刘 刚, 刘春明. 金属学报, 2004; 40: 943)
[10] Wang Z B, Tao N R, Li S, Wang W, Liu G, Lu J, Lu K. Mater Sci Eng, 2003; A352: 144
[11] Ba D M, Ma S N, Meng F J, Li C Q. Surf Coat Technol, 2007; 202: 254
[12] Zhang Y S, Wang K, Han Z, Liu G. Wear, 2007; 262: 1463
[13] Wang T, Wang D P, Liu G, Gong B M, Song N S. Appl Surf Sci, 2008; 255: 1824
[14] Wei Y H, Liu B S, Hou L F, Xu B S, Liu G. J Alloy Compd, 2008; 452: 336
[15] Zhou L, Liu G, Ma X L, Lu K. Acta Mater, 2008; 56: 78
