马氏体基体引入超硬纳米TiC粒子增强低合金耐磨钢磨损性能基础研究

There is a continued and significant interest to develop new generation of low alloy wear resistant steels with high strength, high toughness and high wear resistance combination for equipment manufacturing. Super hard nano particles formed in the matrix of high strength and toughness is considered a potential approach to improve wear resistance and ductility of wear resistance steels. While the nano particles were not easy to nucleation in the matrix of martensite and unstable to control.. In the context of obtaining high wear resistance-high toughness combination, a novel processing route of developing super hard nano particles in the matrix of martensite in low alloy wear resistance steels. The super hard nano particles were beforehand formed in the ferrite or bainite and then controlled it’s growing by off-line heat treatment. Utilizing the concept of formation super hard nano particles in the matrix of martensite, the objective is to fundamentally understand the formation and controlling of nano particles in ferrite or bainite region, as well as it’s influence on the transformation of martensite and growing during off-line heat treatment. The relationship between the size, shape and quantity of the particles and wear resistance were investigated, and the mechanism of deformation and crack propagation during wear will also studied. The proposed research provides a unique experience to researchers where physical metallurgy concepts will be introduced to control the nano precipitation and develop new generation wear resistance steels, impacts the metals-related nanotechnology research being pursued to other fields of microalloyed steel.

高强、高韧和高耐磨性是低合金耐磨钢的发展方向。在高强韧基体上引入超硬纳米级第二相粒子，具有增强耐磨性和减少韧塑性损失的优势。但因低温相变过程中原子扩散受限，第二相粒子在马氏体上直接形核及弥散分布控制困难。.本项目提出预先析出第二相粒子并控制其生长的思路，在马氏体基体中引入超硬纳米TiC粒子(~HV3200)，实现提高耐磨性能和减少韧塑性损失的目的。通过超快冷技术，在铁素体或贝氏体中预先析出超硬纳米粒子，控制离线热处理过程，使其保留和弥散分布在马氏体基体上。研究TiC粒子在马氏体上的热力学、动力学形成条件及控制原理，实现TiC粒子在马氏体基体上稳定弥散分布与控制；分析预先析出粒子对后续马氏体相变的影响以及第二相粒子尺寸、形状及其分布与冲击、高温磨损之间的内在联系，阐明磨损时的变形和裂纹扩展机理，为获得新型高强高韧低合金耐磨钢铁材料提供基础。本研究可以丰富和拓展钢中第二相粒子控制理论和磨损机理，还可以推广应用至其他微合金钢领域。

高强、高韧和高耐磨性是低合金耐磨钢的发展方向。在高强韧基体上引入超硬纳米级第二相粒子，具有增强耐磨性和减少韧塑性损失的优势。但因低温相变过程中原子扩散受限，第二相粒子在马氏体上直接形核及弥散分布控制困难。本项目通过预先析出第二相粒子并控制其生长的方法，在具有良好强韧性的板条马氏体基体中引入了超硬纳米TiC粒子，实现了提高耐磨性能30%以上和减少韧塑性损失的目的。在研究过程中，项目采用超快冷技术，在铁素体或贝氏体中预先析出超硬纳米粒子，控制离线热处理过程，使其保留和弥散分布在马氏体基体上，实现了低温相变马氏体上引入大量弥散分布的TiC粒子。项目研究了TiC粒子在马氏体上的热力学、动力学形成条件及控制方法，实现了TiC粒子在马氏体基体上稳定弥散分布与控制；分析了预先析出粒子对后续马氏体相变的影响以及第二相粒子尺寸、形状及其分布与冲击、高温磨损之间的内在联系，阐明了磨损时的变形和裂纹扩展机理，获得了一种新型高强度、高韧性、高耐磨性的低合金耐磨钢铁材料，并在国内华菱涟钢、南京钢铁、华菱湘钢实现成果转化。.在研究周期内，项目共发表SCI学术论文12篇，申请发明专利2项，培养硕士3人，博士1人；研究结果作为主要创新点之一，获中国金属学会、中国钢铁工业协会冶金科学技术奖一等奖；项目的研究，促进了低合金耐磨钢的发展，具有重要的理论和实践意义。