Experimental and DFT study on cerium inclusions in clean steels
来源期刊：JOURNAL OF RARE EARTHS2021年第4期
论文作者：Xiangjun Liu Jichun Yang Fang Zhang Xiaoyang Fu Hongwei Li Changqiao Yang
文章页码：477 - 486
摘 要：To provide insights into deforming Ce-O-S-Al inclusions in steels and improving the mechanical properties,the evolution process of such harmful inclusions in clean steels was investigated by thermodynamic calculation,metallographic examination and first-principles calculation in this paper.For the tested IF steel,the the rmodynamic analysis results are consiste nt with the calculated formation enthalpy.After Ce addition,the inclusions are transformed from Al2 O3 and TiN-Al2 TiO5-Al2 O3 to Ce2 O3,Ce2 O2 S,CeAlO3,TiN-Al2 TiO5-Ce2 O3 and TiN-Al2 TiO5-Ce2 O2 S composite inclusions,which can be confirmed by metallographic examination.The elastic constants were calculated,and the bulk modulus,Young’s modulus,shear modulus and Poisson’s ratio were evaluated by the Voigt-Reuss-Hill（VRH） approximation.All inclusions except Ce2 O3 show appare nt brittle ness.TiN,Al2 O3,Al2 TiO5 and CeAlO3 present much higher hardness than iron matrix,while the hardness of Ce2 O3 or Ce2 O2 S is close to that of iron matrix.The thermal expansion coefficients of Ce2 O3 and CeAlO3 are close to that of iron matrix,whereas,Ce2 O2 S inclusion has largely different thermal expansion coefficient from iron matrix and may deteriorate the steel performance at higher temperatures.The relatively small differences between Ce inclusions and iron matrix in terms of hardness,toughness,brittleness,and thermal expansion coefficient can explain the improvement of the mechanical properties of the tested steel.
Xiangjun Liu1，Jichun Yang1，Fang Zhang1，Xiaoyang Fu1，Hongwei Li2，Changqiao Yang3
1. School of Materials and Metallurgy,Inner Mongolia University of Science and Technology2. School of Materials Science and Engineering,University of Science and Technology Beijing3. National-Provincial Joint Engineering Research Center for Comprehensive Utilization of Symbiotic-Associated Mineral Waste Resources in Bayan Obo,Inner Mongolia University of Science and Technology
摘 要：To provide insights into deforming Ce-O-S-Al inclusions in steels and improving the mechanical properties,the evolution process of such harmful inclusions in clean steels was investigated by thermodynamic calculation,metallographic examination and first-principles calculation in this paper.For the tested IF steel,the the rmodynamic analysis results are consiste nt with the calculated formation enthalpy.After Ce addition,the inclusions are transformed from Al2 O3 and TiN-Al2 TiO5-Al2 O3 to Ce2 O3,Ce2 O2 S,CeAlO3,TiN-Al2 TiO5-Ce2 O3 and TiN-Al2 TiO5-Ce2 O2 S composite inclusions,which can be confirmed by metallographic examination.The elastic constants were calculated,and the bulk modulus,Young’s modulus,shear modulus and Poisson’s ratio were evaluated by the Voigt-Reuss-Hill（VRH） approximation.All inclusions except Ce2 O3 show appare nt brittle ness.TiN,Al2 O3,Al2 TiO5 and CeAlO3 present much higher hardness than iron matrix,while the hardness of Ce2 O3 or Ce2 O2 S is close to that of iron matrix.The thermal expansion coefficients of Ce2 O3 and CeAlO3 are close to that of iron matrix,whereas,Ce2 O2 S inclusion has largely different thermal expansion coefficient from iron matrix and may deteriorate the steel performance at higher temperatures.The relatively small differences between Ce inclusions and iron matrix in terms of hardness,toughness,brittleness,and thermal expansion coefficient can explain the improvement of the mechanical properties of the tested steel.
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