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采用放电等离子烧结技术(SPS)制备了Nb-20Si-5Al-15Ti-3Cr-5W(原子百分数)多元铌硅系原位复合材料。采用循环氧化试验研究了其高温氧化行为。利用扫描电镜(SEM)、X-射线衍射仪(XRD)和电子探针微区分析(EPMA)进行了微观组织结构分析。结果表明,该复合材料的组织主要由(Nb,Ti,W)_(ss)、Ti、α-Nb_5Si_3、γ-Nb_5Si_3和(Nb,Ti)_5Si_3组成;该材料分别经800℃/100 h、1100℃/100 h循环氧化后,都会在表面生成一层氧化膜。800℃下的氧化膜主要成分为AlNb_(11)O_(29)、Ti_2Nb_(10)O_(29)、TiO_2、SiO_2、Nb_2O_5、Nb_4W_3O_(47)和Cr_2Ti_6O_(15),在多孔氧化膜下,会发生严重的内氧化现象。在1100℃时的氧化膜主要成分为AlNb)_(11)O_(29)、Ti)2Nb_(10)O_(29)、TiO_2、SiO_2、Nb_2O_5及Cr_2WO_6,氧化膜致密性较好,可减缓氧的扩散速率,从而提高合金的抗氧化性,经1100℃,100 h循环氧化后仍有基体剩余。
Nb-20Si-5Al-15Ti-3Cr-5W (atomic percent) multiple niobium silicon in-situ composites were prepared by spark plasma sintering (SPS). Cyclic oxidation test was used to study its high temperature oxidation behavior. The microstructure was analyzed by SEM, XRD and EPMA. The results show that the microstructure of the composite consists of (Nb, Ti, W) _ (ss), Ti, α-Nb_5Si_3, γ-Nb_5Si_3 and (Nb, Ti) _5Si_3. 1100 ℃ / 100 h cycle oxidation, will generate a layer of oxide film on the surface. The main components of the oxide film at 800 ℃ are AlNb 11 O 29, Ti 2 Nb 10 O 29, TiO 2, SiO 2, Nb 2 O 5, Nb 4 W 3 O 47 and Cr 2 Ti 6 O 15. Under the porous oxide film, A serious internal oxidation occurs. The main components of the oxide film at 1100 ℃ are AlNb_ (11) O_ (29), Ti) 2Nb_ (10) O_ (29), TiO_2, SiO_2, Nb_2O_5 and Cr_2WO_6. Diffusion rate, thereby improving the oxidation resistance of the alloy, after 1100 ℃, 100 h cycle oxidation remains after the matrix remaining.