DD26镍基单晶高温合金的高温持久性能各向异性

Anisotropy of high-temperature stress rupture properties of a nickel-base single crystal superalloy DD26

为了研究取向对DD26镍基单晶高温合金持久性能的影响,对实验合金进行了高温蠕变测试.结果表明,持久寿命随取向变化逐渐降低的顺序为:[111]>靠近[001]-[111]边界>靠近[001]>[001]-[011]边界>[011].靠近[111]取向的试样,由于具有较小的Schmid因子,位错不易开动,所以持久寿命最长.而靠近[001]取向的试样具有较大的Schmid因子,致使可以开动的滑移系最多,所以伸长率最大.靠近[001]-[011]边界和[011]取向的试样在蠕变过程中取向会向[001]-[111]边界旋转,并且较大的旋转造成这些取向的试样具有较短的持久寿命.

In order to study the influence of orientation on the stress rupture properties of single crystal superalloy DD26, the creep tests under high temperature were carried out for the experimental alloy. The results show that the stress rupture life gradually decreases with the orientation in the following order as [111]〉 near E001]-[111] boundary〉 near [001] 〉 [0011-[011] boundary〉[011]. Due to the lower Schmid factor at which the dislocations can not be easily operated, the specimen with the orientation near [111] exhibits the longest stress rupture life. However, the specimen with the orientation near [001] has the higher Schmid factor at which the operated slip systems are most, and thus exhibits the largest elongation. For the specimens with the orientation both near [001]-[011] boundary and [011 ], their orientation will rotate towards [ 001]-[111] boundary during the creep tests. And the specimens with the orientation near [001]-[011] boundary and [011] exhibit the lower stress rupture life due to the larger rotation.