退火温度对L-PBF成形镍基粉末高温合金组织和力学性能的影响

Effect of Annealing Temperature on Microstructure and Mechanical Properties of Nickel-Based Powder Superalloy Formed by L-PBF

摘要:

通过对激光粉末床熔化（laser powder bed fusion，L-PBF）成形FGH4096M镍基粉末高温合金进行不同温度的退火处理，采用SEM、EBSD等分析了合金的微观组织结构，并对其进行了拉伸测试，进而研究退火工艺对激光粉末床熔化成形FGH4096M镍基粉末高温合金中显微组织的演变及力学性能的影响。结果表明：随着退火温度的升高，成形态合金中胞状晶组织和柱状晶组织出现了消失的趋势，当退火温度为900 ℃时，开始发现有大量γ′相析出；其硬度值先升高后降低，抗拉强度和屈服强度均呈现先上升后降低趋势，但其断后延伸率在逐渐降低。通过对晶粒取向差分布分析，可知退火能够消除部分残余应力。这一研究成果为激光粉末床熔化成形镍基粉末高温合金性能的提升提供了有效的数据支撑。

Abstract:

Different temperature annealing treatments were conducted on a laser powder bed melted FGH4096M nickel-based superalloy. The microstructure of the alloy was analyzed using SEM and EBSD, while tensile tests were performed to investigate the impact of the annealing process on the microstructural evolution and mechanical properties of the laser powder bed melted FGH4096M superalloy. The results reveal that as the annealing temperature increases, dendritic and columnar crystals gradually disappear in the formed alloy; a significant precipitation of γ′ phase is observed when the annealing temperature is 900 ℃. Additionally, there is a gradual increase in hardness until 800 ℃, along with an upward trend in both tensile strength and yield strength; however, fracture elongation rate remains low at only 5%. Analysis of grain orientation difference distribution indicates that annealing can partially eliminate residual stress. These research findings provide valuable data support for enhancing the performance of laser powder bed melted nickel-based superalloys.