面向高速切削的(Ni,Co)3Al纳米颗粒增强Ti(C,N)基金属陶瓷的形成机制及强韧化机理研究

Based on the serious requirement of excellent strength, toughness and high temperature hardness for the tools in the high speed cutting process of Ni-based superalloy, the project proposes to reinforce strength-toughness and high temperature hardness in cutting process of cermets through the in-situ formation of (Ni,Co)3Al nanoparticles in the binder phase of Ti(C,N)-based cermets, and investigates the key scientific problem in the controllable synthesis and strengthening-toughening mechanism of (Ni,Co)3Al nanoparticles in cermets. On that basis, the project explores the formation mechanism for in-situ formed (Ni,Co)3Al nanoparticles in the binder phase of Ti(C,N)-based cermets, reveals the effects of interface structure between binder phase and (Ni,Co)3Al nanoparticles on the strength and toughness of cermets, investigates the structural stability of (Ni,Co)3Al nanoparticles in the thermal mechanical coupling of high speed cutting process and the effects of (Ni,Co)3Al nanoparticles on the high temperature hardness and abrasion resistance of cermets during the cutting process. The investigation results can achieve the strengthening and toughening of Ti(C,N)-based cermets, support the application of cermets in high speed cutting of Ni-based superalloy and have the great potential applications in the machining of difficult-to-machine materials.

为了满足镍基高温合金在高速切削过程中对刀具材料高强韧性和热硬性的苛刻要求，本项目提出在Ti(C,N)基金属陶瓷的(Ni,Co)粘结相中原位生成(Ni,Co)3Al纳米颗粒强化相来进一步增强Ti(C,N)基金属陶瓷的强韧性和热硬性的学术思路，解决(Ni,Co)3Al纳米颗粒可控合成及其对材料强韧化的关键科学问题。在此基础上，探讨金属陶瓷粘结相中原位形成(Ni,Co)3Al纳米颗粒的机制；揭示(Ni,Co)3Al纳米颗粒与粘结相基体的界面结构关系及其强化作用；进而阐明(Ni,Co)3Al纳米颗粒在高速切削热力耦合作用下的稳定性及其对金属陶瓷刀具热硬性和磨损行为的影响。本项目研究结果可以为高性能Ti(C,N)基金属陶瓷的强韧化及其在高温合金高速切削中的应用提供理论支撑，并对其他难加工材料高效加工的应用研究有重要的参考价值。

Ti(C,N)基金属陶瓷材料具有高硬度、低摩擦系数和优良的耐磨性能，但较差的强韧性使其难以满足高速切削过程对刀具的苛刻要求。项目在金属陶瓷中添加AlN粉末，烧结过程中在粘结中原位生成(Ni,Co)3Al纳米颗粒强化相来增强Ti(C,N)基金属陶瓷的力学性能。研究了(Ni,Co)3Al金属间化合物纳米颗粒的尺寸、结构、其与粘结相基体的界面关系及形成过程。添加了1.0wt.%AlN的金属陶瓷粘结相中弥散分布着(Ni,Co)3Al金属间化合物纳米颗粒，纳米颗粒和粘结相基体的界面为共格结构。粘结相中(Ni,Co)3Al纳米颗粒的存在显著提高了金属陶瓷材料的硬度、抗弯强度和断裂韧性。(Ni,Co)3Al纳米颗粒在高温下具备较好的结构稳定性，改善了金属陶瓷的切削性能。项目为金属陶瓷的强韧化提供依据和指导，有助于拓展Ti(C,N)基金属陶瓷材料的应用领域。