氢含量对再结晶Zr-Sn-Nb管材氢化物微观结构及取向的影响

Influence of hydrogen content on microstructure and crystallographic orientation of hydrides in recrystallized Zr-Sn-Nb tubes

摘要:

虽然已有较多锆合金氢化物的研究，但对于较高氢含量中锆合金氢化物的研究较少。首先对Zr-Sn-Nb管材在400℃下气相渗氢，通过保温不同时间获得三种不同氢含量（147、340、1480 ppm）的渗氢样品。随后采用OM、SEM、TEM和EBSD表征技术，研究了Zr-Sn-Nb管材中氢化物的微观结构、与基体的晶体学取向关系。结果表明：氢含量影响管材中氢化物的取向，α-Zr基体与氢化物之间存在(0001)α∥{111}δ和{10-17}α∥{111}δ两种取向关系。EBSD分析表明氢化物从一个基体晶粒生长向另一个基体晶粒时取向会随着基体晶粒取向的变化而变化。部分锆基体晶粒内同时有晶内氢化物和晶间氢化物，而只有晶内氢化物与锆基体有晶体学取向关系。

Abstract:

Although there are many studies on the hydrides in Zirconium alloys, the microstructure and crystallographic orientation of hydrides with higher hydrogen content has received little attention. The Zr-Sn-Nb alloy charged with 147, 340 and 1480 ppm of hydrogen by gaseous hydriding procedure at 400 ℃ with different holding time. The microstructure and crystallographic orientation of hydrides is investigated by a combination of optical microscopy (OM), scanning electron microscope (SEM), transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) techniques. The results indicate that the orientation is affected by the hydrogen content. The interphase boundary components are used to evaluate the crystallographic orientation of hydrides along with pole figure analyses. We found that there are two orientation relationships between the α-Zr and the hydrides, i.e. (0001)α∥{111}δ and {10-17}α∥{111}δ. EBSD analyses also revealed changes in the orientation of hydrides when hydrides grew from one matrix grain to another to accommodate the matrix modification. Besides, there are many Zr grains with both inter-granular and intra-granular hydrides, and only the intra-granular hydrides exhibit habit relationships with the Zr grains.