激光熔覆制备Fe_3Al金属间化合物覆层的组织结构

Structure of Laser Cladding Fe_3Al Intermetallic Compound Coating

为了研究激光熔覆工艺条件下Fe3A l金属间化合物合金层的组织结构特点,以纯Fe3A l粉+1%Y2O3为原料在钢基体表面激光熔覆Fe3A l金属间化合物,利用扫描电镜、能谱仪、X射线衍射试验方法等对熔覆合金层、合金层与钢基体的结合界面等进行了显微组织与相结构的分析。试验获得了致密、无肉眼可见气孔、夹杂的合金层,合金层与基体间完全冶金结合,但存在裂纹现象;熔覆合金层主要由单相Fe3A l构成,覆层组织为粗大等轴状晶团,等轴状晶团由大量极细小的条状Fe3A l晶粒构成,一些相邻的条状晶粒之间具有基本一致的晶体学取向。

Fe_3Al intermetallic compound was prepared on the mild steel by laser cladding with Fe_3Al powder and 1% Y_2O_3 as materials to study the structure of intermmetallic compound coating.The microstructure and phase structure of the coating and the boundary between the coating and substrate were studied through SEM,EDX and X-ray diffraction analysis techniques.Dense alloy coating without pore and inclusion is obtained which metallurgically bonded with steel but existing a few cracks.The results show that the cladding alloy coating is mainly composed of single-phase Fe_3Al,and the microstructure is coarse equiaxed grain-groups that consist of large amount of fined slug like Fe_3Al grains,between which some adjacent grains have the similar orientation.