铌含量对Mo-Nb合金单晶高温抗内压蠕变性能的影响

采用内部气体介质对管状样品施加双向载荷对铌含量分别为3%及6%(质量分数,下同)的国产Mo-Nb合金单晶的抗内压蠕变性能进行研究。结果表明,随着溶质原子铌含量的增加,Mo-Nb合金单晶的抗内压蠕变性能增强,稳态蠕变速率及对应力的敏感性降低。随着铌含量的增加,铌的固溶强化作用明显增强,在Mo-Nb合金单晶中形成了更多的位错多边结构使得富铌析出物形状发生变化。这些因素都使得钼基体原子的扩散受到更加明显的阻碍,Mo-Nb合金单晶高温抗内压蠕变性能更加优越。

Influence of Niobinum Content on High Temperature Inner Pressure Creep Resistance of Mo-Nb Alloy Single Crystal

The inner pressure creep resistance of two kinds of domestic Mo-Nb alloy single crystal was researched by applying biaxial load on the tube specimen through the inert gas medium. The niobium contents of them were 3wt% and 6wt%, respectively. Results show that the inner pressure creep resistance strengthens, while the steady-state creep rate and the sensitivity to hoop stress drop with the increasing solute niobium atoms. With the increase of niobium content, more multilateral structures of the dislocation form and the shape of the Nb-rich precipitate changes from particle to shaft. These factors induce that the molybdenum atom diffusion become more difficult, and the inner pressure creep resistance of Mo-Nb alloy single crystal becomes more superior.