Formation and Evolution of Oxides in Y‐Zr Microalloyed Fe‐Cr‐Al Alloy

The precipitation, growth, and dissolution of oxide inclusions in Y‐Zr microalloyed Fe‐Cr‐Al electrical heating alloys were studied via heat treatment simulations and modeling. Samples treated at 600°C, 900°C, and 1200°C (water‐quenched, air‐cooled) showed by SEM‐EDS that as‐cast inclusions comprised Y 2 O 3 (48.66%), Y 2 Zr 2 O 7 (34.86%), and ZrO 2 (16.48%) with 2–3 μm sizes. After heat treatment, inclusions decreased; at 1200°C, ZrO 2 in water‐quenched samples rose to 74.87%, while air‐cooled ones recovered Y 2 O 3 to 41.81%, co‐dominant with ZrO 2 . Calculations indicated that higher oxygen contents caused earlier precipitation and coarsening, enlarging inclusions. Y 2 Zr 2 O 7 and ZrO 2 formed at solidification's end, Y 2 O 3 during solidification; raising O from 0.001% to 0.002% advanced Y 2 O 3 formation (solid fraction 0.474→0.279). Growth kinetics ranked rates as Y 2 O 3 > Y 2 Zr 2 O 7 > ZrO 2 , with maximum radius ≈ 14 μm at highest O. Dissolution analysis showed 5 μm Y 2 O 3 dissolved in 9.94 s vs 15.94 s for ZrO 2 , confirming ZrO 2 's superior thermal stability. The main purpose of this study is to clarify the formation, growth, and dissolution mechanisms of oxide inclusions in Y‐Zr microalloyed Fe‐Cr‐Al alloys during heat treatment. Studying the behavior of inclusions is conducive to providing theoretical support for optimizing the preparation and heat treatment processes of this alloy.