冷喷涂Inconel 718高温合金涂层组织及微观硬度

采用冷喷涂技术在马氏体钢表面制备了Inconel 718高温合金涂层,利用SEM、显微硬度计和纳米压痕仪分析了涂层组织和微观硬度。结果表明,涂层厚度可达300μm以上,与基底界面结合良好,底部、中部和顶部涂层微观缺陷数量和尺寸依次增多;冷喷涂沉积过程不会对Inconel 718高温合金粒子的原始组织结构产生显著影响,沉积后粒子的外部轮廓发生了明显的扭曲变形,而心部变形较小;涂层底部、中部和顶部的显微硬度依次降低,与底部涂层相比,中部和顶部涂层显微硬度分别降低10%和21%;涂层平均纳米硬度较原始粒子显著降低,底部和顶部涂层分别降低13.5%和28%;涂层内部微观缺陷分布是影响涂层整体硬度的重要因素。

Microstructure and microhardness of the Inconel 718 superalloy coating prepared by cold gas dynamic spraying

The Inconel 718 superalloy coating was prepared on a martensitic steel substrate by cold gas dynamic spraying(CGDS).The coating’s microstructure and microhardness were characterized by means of SEM,microhardness and nano-indentation testers.The results indicated that the coating’s thickness can reach more than 300 μm,and there exists a good interfacial cohesion between the coating and the substrate.But the quantity and size of defects at bottom,middle and top areas increase gradually.There is no significant change to the original microstructure of the Inconel 718 surperalloy particle after the process of CGDS;and an obvious torsional deformation on the particle’s profile is produced while little deformation at the center part occurs.The microhardness of the coating at the bottom,middle and top areas decreases in turn.Compared with the bottom area,the microhardness of the middle and top areas decreases by about 10% and 21%,respectively.The average nanohardness of the coating is much lower than the original particles,which decreases by about 13.5% at the bottom area and 28% at the top area,respectively.The distribution of micro-defects is an important factor to the microhardness of the coating.