纳米Y_2O_3对过共晶Fe-Cr-C堆焊合金表面微观组织与耐磨性的影响  

Influence of Nano-Y_2O_3 on Microstructure and Wear Resistance of Fe-Cr-C Hardfacing Alloy Surface

作　　者：杨庆祥[1] 赵斌[2] 员霄 蹤雪梅[2] 周野飞[1] 

机构地区：[1]燕山大学亚稳材料制备技术国家重点实验室,河北秦皇岛066004 [2]徐工集团江苏徐州工程机械研究院,江苏徐州221004

出　　处：《表面技术》2015年第4期42-47,53,共7页Surface Technology

基　　金：国家自然科学基金(51271163;51471148)~~

摘　　要：目的研制一种新型添加纳米Y2O3的过共晶Fe-Cr-C堆焊合金,改善堆焊合金粗大的初生M7C3碳化物,提高堆焊合金的耐磨性。方法采用明弧堆焊的方法制作堆焊合金,用金相电子显微镜对其表面微观组织进行观察,用洛氏硬度计对其表面硬度进行测量,用砂带摩擦磨损试验机对其表面耐磨性进行评价,用扫描电子显微镜对其磨损形貌进行观察。最后,利用错配度理论对M7C3的细化机理进行分析。结果过共晶Fe-Cr-C堆焊合金由初生M7C3和共晶组织(共晶M7C3、奥氏体及部分马氏体)组成。未添加Y2O3的堆焊合金初生M7C3比较粗大,其平均尺寸在22μm,硬度为55HRC,磨损量为0.85mg/mm2。经纳米Y2O3改性之后,堆焊合金的初生M7C3尺寸变小,其平均尺寸为16μm,硬度为57HRC,磨损量减少为0.59 mg/mm2,Y2O3的(001)面与正交M7C3的(100)面之间的二维错配度为8.59%。结论 Y2O3可以成为M7C3的非均质形核核心,从而细化了过共晶Fe-Cr-C堆焊合金的初生M7C3碳化物,提高了过共晶Fe-Cr-C堆焊合金表面耐磨性。Objective To develop novel hypereutectic Fe-Cr-C hardfacing alloys （Y2O3-free and Y2O3-modified, respectively） so as to improve the coarse carbides and increase the wear resistance of Fe-Cr-C hardfacing alloys. Methods The hardfacing alloys were deposited by the automatic open arc surfacing welding method. The microstructures were observed by optical microscopy. Meanwhile, the macro hardness of the hardfacing alloy surface was measured by the Rockwell hardness tester. The wear resistance of the hardfacing alloy surface was evaluated by the abrasive wear test. Worn morphology was observed by field emission scanning electron microscopy. Moreover, the mechanism of the microstructure refinement by the two-dimensional misfit theory was also discussed. Results The results showed that the microstructures of the hardfacing alloy consisted of the primary M7 C3 （ M = Cr, Fe） carbide and eutectic structure （eutectic M7C3 carbide＋ retained austenite and its product）. The average size of primary carbide was about 22 μm. The mass loss and the hardness of the Y2O3-free alloy were 0.85 mg/mm2 and 55HRC, respectively. After adding Y2O3, the average size of carbide was about 16 μm. The mass loss of the coating was 0.59 mg/mm2 and the hardness was 57HRC. The two-dimensional lattice misfit between the face （001） of Y2O3 and the face （100） of orthorhombic MTC3 was 8.59%. Conclusion By adding Y2 O3 as the heterogeneous nuclei, the primary M7 C3 carbide was refined and the wear resistance of the hypereutectic Fe-Cr-C hardfacing alloy surface can be improved.

关 键 词：纳米Y2O3 过共晶Fe-Cr-C堆焊合金 M7C3 

分 类 号：TG174.445[金属学及工艺—金属表面处理] TG422.3[金属学及工艺—金属学]