Crystallographic Texture Evolution of ■-Fe4N and Its Influences on Tribological Property of Nitrided Steel
来源期刊：Acta Metallurgica Sinica2018年第4期
论文作者：Yi-Xue Wang Mu-Fu Yan Zhao-Bo Chen Cheng-Song Zhang Yuan You
文章页码：371 - 379
摘 要：The crystallographic texture of ■-Fe4 N in compound layer and its influences on the tribological properties of nitrided steel 38 Cr Mo Al are investigated in the study. The preferred orientation of（200）■ is produced by low-temperature nitriding in atmosphere with low nitrogen–hydrogen ratio and increases with the nitriding time. The preferred orientation of（220）■ appears after 72 h cyclic nitriding. The orientation relationships（0001）ε//（101）■ and [110]ε//[111]■,（111）■//（0001）ε and 011■//[1■10]g,（200）■//（110）■ and [011]■//[111]■, as well as （1■03）ε //（220）■ and [0100]ε//[1■0]■ are established by first-principles method. The misfit of interatomic distance（δ）, determining the phase transition resistance, is calculated. Accordingly, two reaction pathways during nitriding, ■→■ and ■→ε→■, are assumed, which determines the preferred orientations of ■-Fe4 N. Results of wear tests demonstrate that the specimen with preferred orientation of（200）■ exhibits lower frictional coefficient and lower wear rate in comparison with the specimen with（220）■ preferred orientation.（111）■ texture usually relates to the lower frictional coefficient but higher wear rate due to the main slip system parallel to the sliding plane. Therefore, the（200）■ preferred orientation has a positive significance in improving the wear properties of steels.
Yi-Xue Wang1,2，Mu-Fu Yan1，Zhao-Bo Chen2，Cheng-Song Zhang3，Yuan You2,4
1. National Key Laboratory for Precision Hot Processing of Metals, School of Materials Science and Engineering, Harbin Institute of Technology2. School of Mechatronics Engineering, Harbin Institute of Technology3. School of Materials Science and Engineering, Southwest Jiaotong University4. School of Materials Science and Engineering, Qiqihar University
摘 要：The crystallographic texture of ■-Fe4 N in compound layer and its influences on the tribological properties of nitrided steel 38 Cr Mo Al are investigated in the study. The preferred orientation of（200）■ is produced by low-temperature nitriding in atmosphere with low nitrogen–hydrogen ratio and increases with the nitriding time. The preferred orientation of（220）■ appears after 72 h cyclic nitriding. The orientation relationships（0001）ε//（101）■ and [110]ε//[111]■,（111）■//（0001）ε and 011■//[1■10]g,（200）■//（110）■ and [011]■//[111]■, as well as （1■03）ε //（220）■ and [0100]ε//[1■0]■ are established by first-principles method. The misfit of interatomic distance（δ）, determining the phase transition resistance, is calculated. Accordingly, two reaction pathways during nitriding, ■→■ and ■→ε→■, are assumed, which determines the preferred orientations of ■-Fe4 N. Results of wear tests demonstrate that the specimen with preferred orientation of（200）■ exhibits lower frictional coefficient and lower wear rate in comparison with the specimen with（220）■ preferred orientation.（111）■ texture usually relates to the lower frictional coefficient but higher wear rate due to the main slip system parallel to the sliding plane. Therefore, the（200）■ preferred orientation has a positive significance in improving the wear properties of steels.
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