摘要
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。
A multi-element Nb-Si system in-situ composite with the composition of Nb-20Si-5Al-15Ti-5Cr-8W（aP/o） was prepared by spark plasma sintering （SPS） technology. The high temperature oxidation behavior was studied by cyclic oxidation test and the microstructure of the alloy was investigated by SEM, XRD and EPMA. The results show that the microstructure of the composite consists of （Nb, Ti, W）ss, Ti, α-NbsSi3, γ-NbsSi3 and （Nb, Ti）sSi3 phase, and after cyclic oxidation test at 800℃ for 100 h and 1100℃ for 100 h, the composite forms a thick oxide film. At 800℃, the composition of oxide film are mainly composed of A1Nb11O29, TizNb10029, TiO2, SlOe, NbzOs, Nb4WsO47 and Cr2Ti6O15. The severe inner oxidation generates below the porous oxide film. At 1100℃, the composition of oxide film are mainly composed of A1Nbl11O9, Ti2Nb10029, TiO2, SiO2, Nb205 and Cr2WO6. The rate of diffusion of oxygen reduces because of the dense oxide film, and then the oxidation resistance of the alloy improves effectively. There is a little matrix remain after cyclic oxidation resistance at 1100℃ for 100 h.
出处
《热加工工艺》
CSCD
北大核心
2016年第8期143-147,共5页
Hot Working Technology
基金
国家自然科学基金资助项目(51271091)
江西省教育厅科技项目(GJJ12420)
