随着航空发动机涡轮工作温度不断升高，涡轮叶片内腔结构日趋复杂，空心内腔气冷薄壁结构要求涡轮叶片的壁非常薄。针对薄壁试样性能与标准试样相比性能可能有所改变的情况，采用圆柱形标准试样和3种不同厚度的薄壁试样研究了900℃和1030℃条件下第二代定向凝固合金DZ406的持久性能。结果表明：DZ406合金具有明显的薄壁效应，且相同温度应力条件下，试样壁厚越小，持久寿命下降越严重；断口分析表明，合金的持久失效机理由“表面氧化产生的裂纹扩展”和“内部蠕变损伤”2种方式共同作用；持久性能的有效应力与试样表面氧化层厚度的关系表明，表面氧化层厚度对薄壁试样的持久性能具有显著影响。
As the working temperature of aero-engine turbine continues to rise, the inner cavity structure of turbine blades becomes more and more complex. Such hollow air-cooled thin-wall structure requires the very thin wall of turbine blades, while the performance of thin-wall sample may be different compared with standard sample. The stress rupture properties and the fracture character of the second generation directionally solidified alloy DZ406 at 900℃ and 1030℃were studied by using the round bar specimen and three thin-walled specimens with different thicknesses. Results show that the thin-wall effect was very obvious, and under the same test condition, the smaller the wall of the specimen, the more serious the decline of the life. The fracture analysis indicate that the fracture mechanism of DZ406 superalloy by the coalescence of the ‘surface oxidation-crack initiating-crack growth' and ‘inside creep damage'．The relationship between effective stress and oxidation thickness indicates that the surface oxidation had great influence on the durability of the thin-wall specimens.
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