论文部分内容阅读
研究了一种镍基单晶高温合金DD499的[001],[011]和[111]3个晶体取向在典型应力条件下的持久性能。结果表明,持久寿命的取向依赖性与温度和应力有关。760℃,790MPa时,[001]取向的持久寿命明显高于[011]和[111]取向;1040℃,165MPa时,持久寿命由大到小顺序为[111]>[001]>[011],但不同取向的各向异性减弱。利用SEM观察持久断裂后的断口和组织结构表明,760℃,790MPa时,[001]取向试样的断裂特征为解理和准解理混合型断裂,[011]取向为单系滑移引起的剪切断裂,而[111]取向为多系滑移引起的剪切断裂;1040℃,165MPa时,3种取向都为微孔聚集型断裂。
The permanent properties of [001], [011] and [111] 3 crystal orientations of a nickel-base single crystal superalloy DD499 under typical stress conditions were investigated. The results show that the orientation dependence of long-lived life is related to temperature and stress. The long-term life of [001] orientation was significantly higher than that of [011] and [111] orientations at 760 ℃ and 790MPa, and the order of longevity was [111]> [001]> [011] , But the anisotropy of different orientations weakened. SEM observation of the fracture and the structure after the permanent fracture shows that the fracture characteristics of the [001] orientation sample at 760 ℃ and 790MPa are the cleavage and quasi-cleavage mixed fracture [011] Shear fracture, while the [111] orientation is shear fracture caused by multi-line slip. At 1040 ℃ and 165 MPa, all three orientations are micropore-aggregated faults.