热等静压对DD419单晶高温合金组织与持久性能的影响

Effect of Hot-Isostatic Pressing on Microstructures and Stress-Rupture Properties of DD419 Single Crystal Superalloy

在3种条件下对第二代单晶高温合金DD419进行了热等静压(HIP)处理,利用X射线三维成像技术(XRT)对处理后的样品进行表征,研究了热等静压对合金持久性能的影响。结果表明:热等静压处理能够显著降低孔洞的直径和数量。对于热等静压处理充分的样品,其孔隙率极低,持久寿命相较于热等静压之前提高了59%。对于热等静压处理不充分的样品,尽管孔隙率较小,但它们的持久寿命相较于热等静压之前并没有显著提升。由此说明,铸造和热处理过程中产生的孔洞对单晶高温合金的持久寿命有着重要影响,恰当的热等静压工艺对合金的持久性能有着改善的作用。

In this work,the second-generation single crystal superalloy DD419 was treated by hot isostatic pressing(HIP)under three conditions.The samples were characterized by X-ray three-dimensional tomography(XRT),and the effect of HIP on the stress rupture properties of the alloy was studied.The results show that HIP can significantly reduce the diameter and number of pores.For samples with sufficient HIP,the porosity is extremely small and the lifetime is 59%higher than that before HIP.For samples with insufficient HIP,although the porosity is small,their lifetime does not increase significantly compared with that before HIP.It shows that the pores produced in the process of casting and heat treatment have an important effect on the stress rupture life of the single crystal superalloy,and proper HIP process can improve the stress rupture properties of the alloy.