YANG Wangyue
,
ZHANG Jishan
,
CHEN Guoliang
,
TIAN Shusen
,
GENG Qingquan Beijing University of Iron and Steel Technology
,
Beijing
,
China. Institute of Metal Research
,
Academia Sinica. Fushun Steel Works
,
Fushun
,
Liaoning
,
China.
材料科学技术(英文)
The deformation and fracture behaviour of nickel-base superalloy GH698 with different grain size have been studied at 700℃ under fatigue-creep interaction conditions. Compared with coarse-grained specimens, the grain refining process shows obvious effect on the mechanical behaviour of the alloy, i. e. in F and C zones, the fraction of pure fatigue and creep fracture on fracture surfaces is greatly reduced, which decreases and increases the fracture life in zones F and C respectively, in FC and C zones, creep deformation is greatly restrained by the alternating stress component, which increases the fracture life remarkably. It is also proved that in spite of the difference in microstru- tures such as grain size, for a constant tem- perature, a unique life equation t_r=A~n can be used to predict rupture life within the stress region controlled by the same fracture mode.
关键词:
Ni-base superalloy
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null
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null
MA Zongyi YAO Zhongkai Harbin Institute of Technology
,
Harbin
,
China
金属学报(英文版)
The SiC_w/Al composite prepared by squeeze casting has a combination of superior room temperature specific strength and modulus together with excellent thermal properties.The extrusion can make an improvement on the strength and ductility of the composite from 582 MPa as squeeze casted up to 639 MPa,and on the transformation from isotropic to the anisotropic structure.This seems to be explained by the orientation of whiskers and the densification of dislocations in matrix.TEM observation indicates that the stacking fault is the usual planar defect on the SiC_w surface. composite;;SiC whisker;;Al alloy;;microstructure
关键词:
composite
,
null
,
null
,
null
B.W. Wang
,
H. Shen
金属学报(英文版)
Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.
关键词:
solar selective thin film
,
null
,
null
,
null