热等静压对第二代单晶高温合金DD6显微组织和力学性能的影响EI北大核心CSCD

通过1280,1300℃和1320℃3个温度的热等静压实验,对比分析热等静压对第二代单晶高温合金DD6显微组织和力学性能的影响。结果表明:热等静压能够显著减少显微疏松,尤其是经过1300℃/100MPa,4h热等静压处理的合金内部显微疏松含量从0.31%降低到0.04%。提高热等静压温度能显著减少共晶含量。热等静压对合金的持久性能没有明显影响,但能显著提高DD6单晶合金的低周疲劳性能。经过1300℃/100MPa,4h热等静压处理的合金疲劳寿命较经过标准热处理的疲劳寿命提高了一个数量级,这与热等静压显著减少合金中的疏松孔洞相关。

Effect of Hot-isostatic Pressing on Microstructure and M echanical Properties of Second Generation Single Crystal Superalloy DD6

Effects of the hot‐isostatic pressing (HIP) temperature (1280 ,1300 ,1320℃) on microstruc‐tures and mechanical properties of a second generation single crystal superalloy DD 6 were investiga‐ted .T he results show that the HIP treatment significantly decrease the cast porosity number of DD 6 compared with standard treated specimens .Especially ,the cast porosity volume fraction is deceased from 0 .31% to 0 .04% after the HIP treatment of 1300℃/100MPa ,4h .The cast eutectic volume fractions are remarkably reduced with increasing HIP temperature .The HIP treatments nearly un‐changed the creep lives ,While they greatly promote the low cycle fatigue lives .The elimination of cast microspores using the HIP treatment of 1300℃/100M Pa ,4h result in the inhibition of crack initi‐ation during fatigue and improve the low cycle fatigue lives one order of magnitude larger than that af‐ter standard heat treatment .