A novel method for preparing diffusion couple to investigate the interaction between AlN and low-density steel at 1373 K

Abstract

• A novel method for preparing the diffusion couple was performed. • The particle precipitation zone consisting of AlN, Al 2 O 3, and MnAl 2 O 4 was detected. • Fine AlN particles precipitated on the grain boundary during heat treatment. • The formation of oxide particles at the AlN/steel interface was clarified. A novel liquid–metal-suction (LMS) method was proposed to prepare the diffusion couple. The interaction between AlN and low-density steel (LDS) after heating at 1373 K for 10 h was observed. The AlN and LDS were tightly combined, and the interface between AlN and LDS was visible. After heat treatment, the diffusion of nitrogen from the AlN substrate to the LDS matrix resulted in the precipitation of fine AlN particles on the grain boundary. Due to traces of Y 2 O 3 in the AlN substrate, the MnAl 2 O 4 and Al 2 O 3 particles were detected on the steel side near the interface. This LMS method can also be used to investigate the interaction between other types of NMIs and steels during heat treatment.