高性能粉末冶金高速钢清洁、便捷制备技术及其应用基础研究

Powder Metallurgy High Speed Steel(PM HSS), which has an excellent performance both at room temperature and at elevated temperature, is widely applied in the manufacturing of high-performance tools and molds. However, the traditional production process of PM HSS is characterized of long process, large investment of production facilities, and heavy contaminations. Moreover, the production techniques are pretty well monopolized by a few developed countries. In this project, a clean and convenient manufacturing technology for PM HSS with high performance and near-net shape has been proposed. A mixture of elemental and carbides powders were employed as the raw materials, which were subsequently densified and completed sintering by a combination effect of multiply activations, and diffusion alloying in solid state. The mechanical alloying, deoxidizing reaction, segregations of large metal atoms in vacancy, which leads to the diffusion gradients associated with oriented diffusion of Fe, have been investigated respectively and synthetically. Meanwhile, based on the proposed solid-fabrication technology, the novel PM HSSs with high performance can be designed and developed, as well as the new alloying methods. The ultimate aim is to investigate the manufacturing technology of near-net shaping PM HSSs with high performance and complex shape and to develop a creative process for the production of PM HSSs.

粉末冶金高速钢具有优异的室、高温性能，用于工、模具的高端制造。针对传统粉末冶金高速钢制备流程长、设备投入大、污染严重，即限用于材料制备，技术完全被少数发达国家所垄断等问题，本项目提出采用单质粉及碳化物混合粉为原料，通过全固相过程的多重复合活化-反应-扩散-烧结，制备高性能粉末冶金高速钢材料及其近净成形复杂形状件的清洁、便捷制备方法。进一步深入研究机械活化、碳-氧反应活化，以及孔洞周边材料高浓度孔隙/大尺寸原子元素偏聚耦合作用构筑的合金化元素浓度梯度促进Fe元素定向自扩散等致密化机理及其多重复合作用及其机理；同时，利用提出的全固相过程制备技术，设计、研发新型高性能粉末冶金高速钢及其强韧化方法；最后，综合研究高性能粉末冶金高速钢材料制备及其复杂形状件近净成型一体化新技术，探索发展粉末冶金高速钢新型制造技术。

粉末冶金高速钢具有优异的力学性能与广阔的应用场景。项目建立了全固相过程下混合粉反应-活化烧结-扩散-烧结技术基础上的高性能粉末冶金高速钢制备技术体系。揭示了粉末冶金高速钢固相烧结致密化行为，完成了对碳-氧反应活化烧结、孔洞周边高空位浓度带来的合金元素偏聚等多重促进致密化机制的研究工作，同时提出采用LaB6强化粉末冶金高速钢的致密化及力学性能，最终实现了高性能、高纯净度、碳化物细小的粉末冶金高速钢的全固相过程制备。基于项目技术中材料成分可灵活调控的特点，设计、研发了新型高钒粉末高速钢、超高碳含量马氏体不锈钢等新型钢材，并探索了高钒高速钢作为cBN粘结剂的可行性。最终针对实际工业应用，建立了近净成形过程中材料成分、混合料制备参数、冷压压制密度、烧结工艺与材料收缩系数、制品密度分布及性能均匀性的关系，实现了粉末冶金高速钢复杂形状件的近净成形制备，并进行了相关应用测试，为高性能粉末冶金高速钢的国产化、低污染、低能耗、便捷性制造提供了理论及应用研究基础。