FeCr-ODS铁素体合金的氧化+粉锻工艺制备及其微观结构

提出一种氧化+粉锻(粉末锻造)新工艺并用其制备了FeCr-ODS铁素体合金。使用SEM、XPS、EPMA和TEM等手段对其表征,研究了粉末表面和内部氧化物的生成、演变以及合金中纳米氧化物弥散相的种类和分布特征。结果表明,在低温氧化过程中粉末表面生成了一层Fe的氧化膜,在随后的加热过程中粉末表面的O元素转移并与Y和Ti元素反应生成了Y-Ti-O纳米氧化物弥散相。通过纳米氧化物弥散相在粉末成型过程中的演变,阐明了粉锻对位错和纳米氧化物析出相形成的贡献。用这种工艺制备的ODS铁素体合金,大量细小的Y₂TiO₅析出相均匀地分布在基体中,晶界上只有少量大颗粒Y₂O₃。

Preparation and Microstructure of FeCr-ODS Ferrite Alloy Fabricated by Oxidation and Powder Forging

FeCr-ODS ferrite alloy was fabricated via a novel fabrication process of pre-oxidation treatment followed by powder forging proposed by the authors. The prepared alloy was characterized by means of SEM, XPS, EPMA and TEM techniques in terms of the generation, evolution of oxides on the surface and interior of the powder, as well as the type and distribution of oxide nanoparticles in the fabricated ODS ferrite alloy. The results show that an iron oxide film formed on the surface of powders during low temperature oxidation. By the subsequent heating process, the iron oxide could react with Y and Ti to form complex oxide Y-Ti-O nanoparticles. The evolution of oxide dispersoids during the course of fabrication was characterized to clarify the contribution of powder forging to dislocations and nanoscale precipitates. Fine Y₂TiO₅ nanoparticles uniformly distributed in the matrix, and a small number of Y₂O₃ particles aligned along the grain boundaries by this manufacturing method.