采用电弧熔炼法制备了Nb-20Si-10Mo、Nb-20Si-10Mo-3M(M=Cr,Al,Ti)(原子分数)四种Nb-Mo-Si基超高温合金.利用SEM、EDS、XRD等实验技术对铸造合金的相组成与组织形态进行了观察和分析.Nb-20Si-10Mo合金由铌固溶体(Nbss)与βNb5Si3化合物两相构成,其铸造组织包含大量片层状共晶(Nbss-βNb5Si3)组织.少量合金元素Cr(3 at%)能够改变Nb-20Si-10Mo合金的相平衡关系,Nb-20Si-10Mo-3Cr的铸造组织中不仅存在Nbss和βNb5Si3,而且还出现少量Cr2Nb相;而添加合金元素Al、Ti(3 at%)并不改变Nb-20Si-10Mo合金的相平衡关系.添加Cr使Nbss-βNb5Si3共晶组织失去了平直片层特征;Al有利于共晶组织中片层状共晶形成;添加Ti使共晶组织呈现羽毛状特征.合金化使Nb与βNb5Si3的晶格常数发生变化:Nb的晶格常数均变小;Nb-20Si-10Mo-3Cr合金中βNb5Si3的c/a值减小,其它3种合金中βNb5Si3的c/a值增大.
参考文献
| [1] | Bewlay B P,Jackson M R,Zhao J C,Subramanian P R.A review of very-high temperature Nb-silieide-based composites[J].Metallurgical and Materials Transactions A,2003,34A (10):2043-2052. |
| [2] | Kim W Y,Tanaka H,Hanada S.Microstrueture and high temperature strength at 1773 K of Nb/Nh5Si3 composites alloyed with molybdenum[J].Intermetallics,2002,10 (6):625-634. |
| [3] | Tabaru T,Hanada S.High temperature strength of Nb3Al-base alloys[J].Intermetallics,1998,6(7/8):735-739. |
| [4] | Kim J H,Tabaru T,Sakamoto M,Hanada S.Mechanical properties and fracture behavior of an Nbss/Nb5Si3 in-situ composite modified by Mo and Hf alloying[J].Materials Science and Engineering A,2004,372(1/2):137-144. |
| [5] | LiW,YangHB,ShanAD,ZhangLT,WuJ S.Effect of Mo addition on phase stability and high-temperature strength of NbSi2/Nb5Si3 composites[J].Materials Transactions JIM,2004,45(12):3282-3285. |
| [6] | 刘东明.Nb-Si-W-X超高温合金组织与力学性能研究[D].北京:北京航空航天大学,2006;2.Liu Dongming.Microstructure and mechanical behaviors of ultra-high temperature Nb-Si-W-X alloy[D].Beijing:Beihang University,2006:2. |
| [7] | Subramanian P R,Mendiratta M G,Dimiduk D M,Stucke M A.Advanced intermetallic alloys-beyond gamma titanium aluminides[J].Materials Science and Engineering A,1997,239/240(2):1-13. |
| [8] | Mendiratta M G,Lewandowski J J,Dimiduk D M.Strength ductile-phase toughening in the two-phase Nb/Nb5Si3 alloys[J].Metallurgical Transactions A,1991,22A(7):1573-1583. |
| [9] | Ma C L,Li J G,Tan Y,Tanak R,Hanada S.Microstructure and mechanical properties of Nb/Nb5 Si3 in situ composites in Nb-Mo-Si and Nb-W-Si systems[J].Materials Science and Engineering A,2004,386(1/2),375-383. |
| [10] | Ma C L,Tanaka H,Kasama A,Tanaka R,et al.Phase equilibria in Nb-Mo-rich zone of the Nb-Si-Mo ternary system[J].Materials Transactions JIM,2000,41(10):329-1336. |
| [11] | Sekido N,Kimura Y,Miura S,Mishima Y.Solidification process and mechanical behavior of the Nb/Nb5Si3 two phase alloys in the Nb-Ti-Si system[J].Materials Transactions JIM,2004,45(12):3264-3271. |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%