研究了晶向为＜111＞Mo-Nb合金单晶的高温力学性能.实验结果表明,随着少量溶质原子Nb的加入,Mo-Nb合金单晶的高温强度获得了明显的提高.在1873 K和Nb含量在0～6%范围内时(文中合金元素Nb含量均为质量百分比,下同),Nb含量每增大1%,材料的高温屈服强度就增加约16～25 MPa,当Nb含量在0～3%范围内时,随着Nb含量的增加,塑性急剧下降,而在3%～6%范围内时其下降幅度趋于平缓;同时,随着Nb浓度的增大,更多的Nb溶质原子增大了原子间扩散阻力,使材料高温稳态蠕变率减小,大大提高了材料的高温抗蠕变性能;在1773 K/10 MPa时Mo-Nb合金单晶的稳态蠕变率较纯Mo单晶的降低了3～4个数量级,分析认为其蠕变机制为扩散蠕变.
The high temperature mechanical properties of Mo-Nb alloy single crystals with＜111＞orientation were studied.The experimental results showed that significant increase in high temperature mechanical properties could be achieved with small amount addition of substitutional alloying element Nb.The yield strength at 1873 K increased approximately 16～25 MPa with Nb increasing 1%in the range of 0～6%Nb.The elongation of materials drastically decreased from 0 to 3%.but it appreciably reduced when the concentration of Nb was in the range of 3%～6%.On the other hand.the steady state creep rates significantly decreased with addition of niobium due to the augment of the force to retard directional diffusion among atoms.The steady state creep rate of Mo-Nb alloy single crystal was three to four orders of magnitude lower than that of purity Mo single crystal at 1773 K/10 MPa.Its creep mechanism of Mo-Nballoy single crystals was a diffusion creep.
参考文献
| [1] | Nikolacv Y V;Kolesov V S.Molybdenum and tungsten single crystal alloys with abnornudly high creep strength for space nuclear power and propulsion systems[A].New York:American Institute of Physics Press,1993:267. |
| [2] | R.H. Zee;Z. Xiao;B.A. Chin .Processing of single crystals for high temperature applications[J].Journal of Materials Processing Technology,2001(1/3):75-80. |
| [3] | Baars R E.Evolution of Refractory Metals and Alloys[M].Pennsyvania:The Minerals,Metals & Materials Saciety,1994:185. |
| [4] | Savitsky E M.Single Crystal Refractory Metals,Alloys and Compounds[M].Moscow:Nauka Press,1984:196. |
| [5] | 冯端;吴希俊;孔庆平.金属物理[M].北京:科学出版社,1999:586. |
| [6] | Tachkova N G;Zubarev P V;Yastrebkov A A;fanasev N G .High temperature creep of monocrystalline Mo-Nb alloys[J].Russian Metallurgy,1987,1:153. |
| [7] | Mopryhoba H H.Molybdenum Alloys[M].北京:冶金工业出版社,1984:20. |
| [8] | Poirier J P.Creep of Crystals[M].London:cambridge University Press,1985:194. |
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