论文部分内容阅读
研究了锆-4合金经β相水淬和重新经700℃-1h退火后的显微组织，以及在400℃过热蒸汽中的耐腐蚀性能。β相水淬后得到非常细小的板条状晶粒，无第二相析出，晶粒内位错密度较高，还有残留的β-Zr（a=0．355mm），这种组织的耐腐蚀性能差，易形成白色及灰白色氧化膜。重新经700℃、1小时退火后可得到两种显微组织，一种是扳条状晶粒发生粗化，在晶界上析出了Zr（Fe，Cr）2第二相，使耐腐蚀性能明显改善，得到黑色光亮的氧化膜。另一种是等轴大晶粒组织，这是再结晶后晶粒发生异常长大的结果，晶粒直径达到0．2～0．5mm，这种组织的耐疖状腐蚀性能很差，在400℃过热蒸汽中腐蚀时，形成了明显的疖状腐蚀斑。
The microstructure of zirconium-4 alloy after β-phase water quenching and re-annealing at 700 ℃-1h were studied, and the corrosion resistance of the zirconium-4 alloy in superheated steam at 400 ℃ was studied. β-phase water quenching to obtain very fine lath-shaped grains, no precipitation of second phase, high dislocation density in grains, and residual β-Zr (a = 0.355mm) Corrosion performance is poor, easy to form white and gray oxide film. After re-annealing at 700 ° C for 1 hour, two kinds of microstructure can be obtained. One is that the wand-like grains coarsen and the second phase of Zr (Fe, Cr) 2 precipitates on the grain boundaries to make the corrosion resistance Obvious improvement, get black light oxide film. The other is the large equiaxed grain structure, which is abnormal recrystallization grain growth results, the grain diameter of 0.2 ~ 0.5mm, the corrosion resistance of this structure is poor, in the 400 ℃ superheated steam corrosion, the formation of a clear scallop corrosion spots.