陈国胜
,
伍伯华
,
周乐澄
,
李玉清
金属学报
研究了Nb在Fe-Ni-Cr-W-Mo-Ti合金中的中高温强化作用。当Nb含量低于1.22wt-%时,合金的650℃拉伸强度、塑性、持久寿命和疲劳极限随Nb含量升高而提高。Nb促使MC相均匀分布,细化晶粒,增加γ′相的数量和提高其稳定性。当Nb含量为1.22wt-%时,小颗粒Laves相在晶界上弥散析出,有利于合金的综合性能;只有当Nb含量过高时,Laves相在晶界过量析出,才使合金性能恶化。
关键词:
Nb
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Fe-base superalloy
,
strengthening
J.M.Yang
,
J.C.Lei
,
J.P.Li and P.Cheng Dept. Mater.Sci.and Eng. Xi'an Institute of Technology
,
Xi'an 710032
,
China
金属学报(英文版)
BAS (BaAl 2Si 2O 8) glass ceramic was prepared by a sol gel process and the SiC W/BAS composites were fabricated by hot pressing. The transformation from hexacelsian to celsian, the microstructure and mechanical properties of the composites was investigated. The results show that the transformation promoted by adding celsian seeds is retarded in the composite by the presence of SiC whisker. SiC whisker has a good effect of improving the mechanical properties of BAS glass ceramic matrix. The toughening mechanisms are crack deflection and whisker fracture. The strengthening mechanism is loading transition. The amorphous phase at SiC W/BAS matrix interface damages the fracture toughness and high temperature strength of the composites.
关键词:
glass ceramic
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