Ti40合金的超高温氧化行为研究

Super-high Temperature Oxidation Behavior of Ti40 Alloy

对Ti40合金进行1000~1500℃的超高温氧化实验。应用SEM、OM、XRD和EDS分析氧化表面以及氧化表面到基体的组织和元素的变化。结果表明,Ti40合金在1000~1500℃氧化过程中,氧化表层分别经历了V2O5的熔化蒸发、TiO_2晶粒的长大,以及表面氧化层由于TiO_2的生长应力而导致的开裂剥落的过程。当氧化层脱落后,原有的氧化次表层推至氧化表面,形成致密的、具有较好保护作用的TiO_2和Cr_2O_3混和氧化层。同时,在氧化层和基体界面依然稳定存在V、Cr元素的富集层。TiO_2、Cr_2O_3混和氧化层和V、Cr元素的富集层使得氧化表层脱落后合金依然具有良好的抗O元素扩散能力。

The oxidation behaviors of Ti40 alloy in the temperature range of 1000~1500 oC were investigated. The microstructure and element evolution of the oxide surface and from surface to matrix were determined by SEM, OM, XRD and EDS. Results show that V2O5 evaporates and then the TiO2 grains grow on the oxide surface. At last, the oxide film cracks and peels off due to the growth stress exceeding the oxide film strength. After the oxide layer peels-off, the sub-surface turns into the oxide surface, which is constituted of Cr2O3 and TiO2, increases the density of oxide layer markedly. The new mixture oxide surface has a good ability to resist oxidation. An enrichment zone of V and Cr exists between the oxide layer and the matrix. The mixture oxide layer formed by Cr2O3 and TiO2, and the enrichment zone of V and Cr elements prevent the oxygen element from diffusing after the oxide film peeling-off.