Co-Ni-Al复合粘结硬质合金的相图热力学及微结构控制机理研究

因为Co是稀缺的战略资源，所以将具有优异抗氧化和耐腐蚀性能的Ni-Al金属间化合物与 Co复合形成粘结相逐渐成为了硬质合金粘结相改性的一个重要研究方向。材料的性能主要取决于组织结构，掌握Co-Ni-Al复合粘结硬质合金的热力学信息是工艺参数优化和合金设计的关键。本项目拟以W-C-Co-Ni-Al五元系为研究对象开展如下研究：1）发展耦合关键实验、相图计算和第一性原理计算的科学方法，获得该体系的热力学描述；2）基于计算模拟，设计具有工业应用背景的模型合金，获得传统硬质合金中无法精确测定的相平衡信息，验证并完善所建立的热力学描述；3）基于热力学模拟开展微结构的实验表征，研究各种工艺参数对组织结构的影响，掌握Co-Ni-Al复合粘结硬质合金微结构的控制机理。本项目的完成可望为Co-Ni-Al复合粘结硬质合金的开发设计奠定理论基础，并为其它硬质合金的成分设计和微结构控制提供一种可借鉴的科学方法。

Because Co is a scarce strategic resource, choosing a composite binder of Co and Ni-Al intermetallic compound，which is of good resistance to oxidation and corrosion, has gradually become an important research direction in the field of binder modification of cemented carbide. The performance of materials is largely dependent on their microstructure. Knowledge of the thermodynamic data of the Co-Ni-Al composite bonded cemented carbide is the key to the process parameter optimization and alloy design. Choosing W-C-Co-Ni-Al multicomponent system as the target, the present proposal is devoted to: 1) develop a scientific method of combining key experiment, CALPHAD approach and first-principles calculation to establish an accurate thermodynamic description of this system, 2) design model alloys under the background of industrial application based on thermodynamic simulations in order to obtain the phase equilibrium data which could not be accurately determined in traditional cemented carbides, validate and further refine the established thermodynamic description, and 3) conduct experimental characterization of microstructure with the aid of thermodynamic simulations to study the influence of various process parameters on the microstructure, and then clarify the control mechanism of microstructure of Co-Ni-Al composite bonded cemented carbides. The completion of this project is expected to lay a basis of theoretical importance for the design of Co-Ni-Al composite bonded cemented carbides, and provide a scientific method for the design of alloy composition and the control of microstructure for other cemented carbides.