含纳米稀土氧化物过共晶Fe-Cr-C-M(Ti,Nb,V)堆焊合金微观组织演变与耐磨性关系研究

The wear resistance of the hypereutectic Fe-Cr-C alloy can be decreased because M7C3 primary carbide existing as large block form in hypereutectic Fe-Cr-C alloy is prone to peel off the surface of the work piece easily. By means of hardfacing method, the hypereutectic Fe-Cr-C-M(Ti,Nb,V) with micro-alloying elements such as Ti, Nb and V can be manufactured, then nano RE oxides such as CeO2, La2O3 and Y2O3 will be added. The effects of micro-alloying element and RE oxide on the microstructure and phase structure of the hypereutectic Fe-Cr-C-M(Ti,Nb,V) alloy will be investigated. The relationship between the Ti, Nb and V contents with the size of M7C3 carbide, and that between the RE oxide addition with the size of MC carbide will be establishmented. By observing the wear morphologies of the hypereutectic Fe-Cr-C-M(Ti,Nb,V) with elements Ti, Nb and V as well as nano RE oxides and measuring the friction coefficient and weight lose curve, the relationship between the microstructure evolution and wear resistance will be establishmented. According Bramfitt's theory, the effectiveness of MC carbide as heterogeneous nuclei of primary M7C3 carbide and that of RE oxides (compounds) as heterogeneous nuclei of the primary MC carbide will be discussed. By First Principle Method, the interface relationship between MC carbide and M7C3 carbide, and that between RE oxides (compounds) and MC will be calculated, which can provide theoretic foundation for understanding the mechanism of the wear resistance of the hypereutectic Fe-Cr-C-M(Ti,Nb,V) alloy.

过共晶Fe-Cr-C合金因大块状M(Cr,Fe)7C3初生碳化物易从基体中剥落，降低了其耐磨性。本申请在采用堆焊方法制备含微合金化元素（Ti、Nb和V）过共晶Fe-Cr-C-M(Ti,Nb,V)合金基础上，再添加纳米稀土氧化物（CeO2、La2O3和 Y2O3)。研究微合金化元素和稀土氧化物对其微观组织和相结构的影响，建立Ti、Nb、V含量与M7C3型碳化物和稀土氧化物加入量与MC型碳化物之间的细化关系。通过观察不同Ti、Nb、V含量和稀土氧化物加入量合金的磨损形貌，测定其摩擦系数和失重曲线，建立其微观组织演变与耐磨性的关系。借助于错配度理论，计算MC型碳化物成为M7C3型碳化物和稀土氧化物（化合物）成为MC型碳化物非自发形核核心的有效性。通过第一性原理计算，建立MC型碳化物与M7C3型碳化物和稀土氧化物（化合物）与MC型碳化物之间的界面关系。为揭示提高该合金耐磨性机理提供理论依据。

在过共晶Fe-Cr-C-M(Ti,Nb)合金中，优先生成的M(Ti,Nb)C型初生碳化物可以细化随后生成的M(Cr,Fe)7C3型碳化物，虽然可以改善合金的耐磨性，但仍然不能满足增材制造领域对其更高性能的要求。.本申请通过在药芯焊丝中加入纳米稀土氧化物（CeO2、La2O3和Y2O3），采用堆焊方法制备含稀土氧化物的过共晶Fe-Cr-C-M(Ti,Nb)合金，系统分析该合金微观组织和相结构特点，建立稀土氧化物加入量与MC型碳化物尺寸之间的定量关系。通过测定过共晶堆焊合金的摩擦系数和失重曲线，建立微观组织演变与耐磨性的关系。借助于热力学和错配度理论计算，分析合金组织中稀土化合物生成规律以及稀土化合物成为MC型碳化物非自发形核核心的有效性。通过第一性原理计算，建立稀土化合物和MC型碳化物之间的界面关系。.本项目通过研制含MC型初生碳化物的过共晶Fe-Cr-C-M(Ti,Nb)合金，确定了稀土元素在过共晶Fe-Cr-C-M(Ti,Nb)合金中的存在形式，建立了过共晶Fe-Cr-C-M(Ti,Nb)合金中稀土化合物（夹杂物）与MC型初生碳化物之间界面错配的关系，揭示了稀土氧化物细化过共晶Fe-Cr-C-M(Ti,Nb)合金中MC型初生碳化物的机理。.本项目在《Materials Today Communications》、《Scientific Report》、《Journal of Alloys and Compounds》、《Materials and Design》、《Applied Surface Science》、《Materials Letters》、《Materials Science & Engineering A》、《Materials Characterization》、《Surface & Coatings Technology》、《Journal of Materials Research》、《Welding Journal》、《Wear》、《Journal of Rare Earths》等国际刊物发表学术论文40篇，其中被SCI收录37篇，EI收录3篇，授权国家发明专利2项，公开国家发明专利5项；撰写学术著作1部。