S.S. Xie
,
X.F. Pan
,
T.L. Wang
,
Z.X. Wang
,
H.C. Yang and Q. Wang ( School of Materials and Metallurgy
,
Northeastern Universityl Shenyang 110006
,
China)( School of Materials and Metallurgy
,
Northeastern Universityl Shenyang 110006
,
China)( School of Materials and Metallurgy
,
Northeastern Universityl Shenyang 110006
,
China)( School of Materials and Metallurgy
,
Northeastern Universityl Shenyang 110006
,
China)( Institute of Metal Research
,
The Chinese Academy of Science
,
Shenyang 110015
,
China)( Liaoning Machinery Industry Foreign Trade Co. Ltd.
,
Shenyang 110002
,
China)
金属学报(英文版)
Threshold stress values, muging from ～8 to 16MPa·m1/2 can be obtained in a Ni-base alloy GH586 by varying the microstructure through heat treatments. The threshold and low crack growth rate behaviors at room temperature, with varying groin size and γ'-distribution, have been investigated. The results indicate that grain size is an important microstructurol parameter that affects fatigue crack growth threshold and propagation behaviors, as the values of △Kth increase with increasing grain size, but the γ' -distribution also has important effect. Analyses show that the effects of groin size on threshold and low crack-growth rate behavior result from heterogeneous deformation and roughness-induced crack closure due to crystallographic slipping and cracking in coarse microstructure. The higher △Kth and lower fatigue crack growth rate with increasing amounts of fine γ' phases are closely related to less damage accumulation level in deformation zone of crack-tip resulted from heterogeneous deformation due to dislocations' shearing γ' precipitates.
关键词:
superalloy GH586; fatigue crack growth; threshold; grain size;γ'-distribution
