一种高W、Mo含量Ni_3Al基合金的高温氧化行为

High Temperature Oxidation Behavior of a Ni_3Al Base Alloy Containing High Contents of W and Mo

研究了一种高W、Mo的Ni3Al基合金的1050℃静态抗氧化行为,并采用扫描电镜对不同时间氧化后合金的氧化层形貌进行分析,利用X射线衍射仪分析氧化产物的种类和数量,氧化动力学研究表明,合金的氧化动力学曲线不遵循抛物线规律,以W代Mo,能一定程度上改善高Mo的Ni3Al基合金的1050℃抗氧化性能。1050℃/100h静态氧化产物主要为NiO,NiAl2O4和NiWO4,外层氧化镍与内氧化层之间为结合薄弱区,仅氧化1h后,在冷却过程中,该区域就产生大面积开裂,致使外氧化层脱离。随氧化时间增长,合金/氧化层界面的NiAl2O4/Al2O3阻挡层逐步形成,在氧化100h时基本连续,有效降低了合金的氧化速率。

The isothermal oxidation behavior of a Ni3Al base alloy containing high contents of W and Mo at 1050℃ was studied. The morphology of oxide scale of this alloy after oxidized for various time were observed by the scanning electron microscope, and types and amounts of the oxides were also analyzed by a X ray diffraction-meter. The results showed that the oxidation kinetic of this ahoy didn＇ t follow the parabolic rule, and the substitution of W for some Mo could improve the oxidation resistance of the alloy at 1050℃ in some extent. Oxidation products after oxidized at 1050℃ for 100h were mainly NiO,NiAl2O4 and NiWO4. Cracks were found at outer NiO oxides and the inner multi-oxides interfaces in large areas during the process of cooling after oxidized for only 1 h, which might attributed to the weak connection of the two layers leading the spallation of the outer NiO layer in the end. An inner oxidation resistance NiAl2O4/Al2O3 formed gradually with time between the alloy and oxides interface, and became almost continuously after 100h, which reduced the oxidation rate of the alloy effectively.