T.H Xi
,
Z.X. Yuan and Z.S. Yu (Research Institute of Wuhan Iron & Steel (Group) Company
,
Wuhan 430080
,
China)(Department of Materials
,
Wuhan Yejin University of Science and Technology
,
Wuhan 430081
,
China)(Department of Materials Physics
,
Beijing University of Science and Technology
,
Beijing 100083
,
China)
金属学报(英文版)
The effect of Ce on the oxidation behaviour of undoped and B-doped Ni3 Al has been studied. Ce can refine Al2O3 grains produced in the course of oxidation of polycrystalline Ni3Al, accelerate the diffusion of oxygen along Al2O3 grain boundaries,and promote the growth of Al2O3 grains. As a result, the quantity of less-protective NiO decreases. The oxidation resistance of 0.011% Ce-doped alloy is the best of all Ce-doped Ni3Al alloys. Because B is benefitial to the formation of Al2O3 and Ce can refine Al2O3 grains, the oxidation resistance of the alloy containing both B and Ce is the best.
关键词:
Ni_3Al
,
null
,
null
G.F. Zhou
,
M. B. Wen
,
P. H. Li and X. L. He 1) National Enterprise Technology Center
,
Wuhan Iron & Steel Group Co.
,
Wuhan 430080
,
China 2) University of Science and Technology Beijing
,
Beijing 100083
,
China
金属学报(英文版)
The stress relaxation curves of Ultra-Low Carbon Bainitic(ULCB) steels with different Cu and B contents were measured by using Gleeble-1500 dynamic thermal-mechanical simulator. The results show that Cu and B added can accelerate the strain-induced precipitation reaction, and the effect of Cu and B is even more obvious with Cu and B combined addition or Cu content increased. The TEM analysis of precipitate engendered at the temperature of 850℃ C indicate that Nb(C,N) precipitate nucleates dominantly on the dislocation line, and grows with holding time extended while the precipitate particle size increases from 5 nm to 17 nm.
关键词:
stress relaxation
,
null
,
null
Q. F. Wang
,
J. H. Liu
,
Z. Y. Li
,
P. H. Li
,
G. F. Zhou and X. Chen( 1) Huazhong University of Sci. & Tech.
,
Wuhan 430074
,
China 2) Technology Center of WISCO
,
Wuhan 430080
,
China)
金属学报(英文版)
The microstructure and properties of stmulated heat affected zone (HAZ) of laser welded ULCB600 steel were investigate by applying the simulation technique with gleeble - 2000 dynamic thermal - me - chanical simulator.The influence of the preheat condition on the microstructure and properties of simu- lated HAZ of laser welded plate was also studied in order to evaluate the feasibility of reducing arisk that the ductility and toedness of HAZ may be poor by using preheat treatment.The results indicate that the grain size of laser - welded HAZ simulated is very small no matter if there is preheat, the toughness of simulated HAZ is therefore improved comparing to the base metal,and there is no obvious brittle - ductile transition in the range from - 80℃ to 20℃. The TEM analyses of sub -microstruc- ture also discover that microstructure constituent of both simulated HAZ is dominative lath martensite. However, the shaf of martensite is relatively coarse,and the dislocation density is relatively high for simulated HAZ with 200℃ preheat because of slower cooling rate. Combination of these tow factors is responsible for farer bardness and better toughness of simulated HAZ with preheat condition.
关键词:
physical simulation laser beam welding
,
null
,
null
