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本文采用“机械合金化-冷压成形-真空烧结”技术制备了Ti-8Si-1.4Zr、Ti-8Si-1.4Zr-0.1Y2O3和Ti-8Si-1.4Zr-0.3Y2O3三种合金(wt.%),利用SEM扫描电镜及EDS能谱分析仪、X射线衍射仪对烧结和氧化试样的表面及横截面形貌、物相组成进行分析,并对比了三种合金在700℃、800℃和900℃高温下的抗氧化性能来研究氧化机理。结果表明:添加Y2O3能显著提高Ti-8Si-1.4Zr合金的抗氧化性能,减小氧化层厚度,随氧化温度升高氧化膜逐渐增厚,氧化产物尺寸增大,呈朝棱柱状形态生长趋势。700℃下,所有合金都达到完全抗氧化等级,但添加Y2O3后平均氧化速度大幅降低,抗氧化性提升;800℃下,仅有Ti-8Si-1.4Zr-0.1Y2O3配方合金达完全抗氧化等级;900℃下,所有配方合金都在抗氧化等级以内。各配方合金氧化膜组成稍有不同,但氧化膜基本上由表面TiO2氧化层、TiO2与SiO2构成的复合氧化层构成,其中各氧化层中可能还包含部分TiO、Ti2O3和Ti3O5等低价态钛的氧化物以及少量ZrO2或(Ti,Zr)O2相氧化物。
In this paper, three kinds of Ti-8Si-1.4Zr, Ti-8Si-1.4Zr-0.1Y2O3 and Ti-8Si-1.4Zr-0.3Y2O3 alloys were prepared by mechanical alloying-cold forming and vacuum sintering ), The surface and cross-sectional morphology and phase composition of the sintered and oxidized samples were analyzed by SEM and EDS EDS, and the phase composition of the three alloys at 700 ℃, 800 ℃ and 900 ℃ high temperature oxidation resistance to study the oxidation mechanism. The results show that the addition of Y2O3 can significantly improve the oxidation resistance of Ti-8Si-1.4Zr alloy and decrease the thickness of the oxide layer. With the increase of the oxidation temperature, the oxide film gradually thickens and the size of the oxidation products increases, presenting a prism-like morphology . At 700 ℃, all the alloys reached full oxidation resistance level, but the average oxidation rate decreased sharply after addition of Y2O3, and the oxidation resistance increased. At 800 ℃, only Ti-8Si-1.4Zr-0.1Y2O3 formulated alloy reached full oxidation resistance At 900 ° C, all formulated alloys are within the antioxidant rating. The alloy oxide film has a slightly different composition. However, the oxide film basically consists of a composite oxide layer consisting of a surface TiO2 oxide layer, TiO2 and SiO2, and each of the oxide layers may also contain some titanium atoms of lower valence state such as TiO, Ti2O3 and Ti3O5 Oxide and a small amount of ZrO2 or (Ti, Zr) O2 phase oxide.