Y.S.Wu
,
D.Y. Liu
,
B. Cao
,
F. L. Wang
,
X.Y. Wang
,
Z.Fang and Z.G.Du (Department of Surface Science and Corrosion Engineering
,
University of Science and Technology Beijing
,
Beijing 100083
,
China)
金属学报(英文版)
The electrochemical behaviour, including free corrosion potential, free corrosion current density and polarization curve, of various thermal history zones on the weldment was measured in this paper. The weldment consisted of matrix, tempering zone. incomplete normalized zone, normalized zone, overtemperature zone, fusion line zone and weld metal zone. The electrochemical behaviour of the ferrite, pearlite and mixed structure in various zones have successfully measured. The results showed that there was a difference of free corrosion potential which is smaller than ca. 200mV between various zones and about 20-150mV potential difference between ferrite and pearlite in every zone. The free cormsion potential of fusion line zone was the most negative between various zones. The free corrosion potential of pearlite was some dozens mV more negative than ferrite. The corrosion course of various zones and of different phase structures on the weldment and their effect on corrosion attack of weldment were discussed.
关键词:
weldment
,
null
,
null
,
null
L.Y. Dai
,
B. Cao
,
M. Zhu
金属学报(英文版)
The cryogenic milling and milling in conjunction with dielectric barrier discharge plasma (DBDP) have been separately set up. The combined effect of low temperature and plasma on ball milling has been investigated by examining the refinement of particle size and grain size of iron powder using scanning electron microscopy, X-ray diffraction, and small angle X-ray scattering. It was found that the mean size of iron particles could reach 104nm only after 10 hours of ball milling in conjunction with DBDP, whereas a minimum average grain size of 8.4nm was obtained by cryomilling at －20℃; however, it is difficult to refine the particle size and grain size under the same milling condition in the absence of DBDP and cryogenic temperature.
关键词:
ball milling
,
null
,
null
