基于增材制造的硬质合金粉末研究现状

Research status of cemented carbide powders based on additive manufacturing

硬质合金是由难熔金属碳化物(WC,TiC,NbC等)和金属粘结相(如Fe,Ni和Co)组成,通过粉末混合、压制然后烧结而成。然而传统的粉末冶金成形方法模具成本高,难以形成复杂零件。相比之下,增材制造(3D打印)采用数字化叠层加工技术,能够实现快速精准的成形。研究与开发适于增材制造的硬质合金粉末是其中的关键一步,目前,增材制造的硬质合金粉末制备方法主要分为以下4类:机械合金化法、球形WC粉末表面包覆技术、喷雾干燥技术、等离子体球化技术,这4种方法在制备原理、成本和成形方法的灵活性上均有所不同。因此,综述了适用于增材制造成形的硬质合金粉末的4种制备方法,并对制备粉末的特性以及成形性能进行了对比,总结了粉末制备原理、各自的优缺点以及适用的增材制造成形工艺,希望可以推动增材制造成形硬质合金的研究发展。

Cemented carbides, composed of refractory metal carbide(WC, TiC, NbC, etc.) and metallic binder phases(such as Fe, Ni and Co), are prepared by powder mixing, pressing, and then sintering. However, the traditional powder metallurgy method is expensive to fabricate molds, and it is difficult to make complex parts. In contrast, additive manufacturing(AM, also named as "3D printing") adopts digital lamination processing technology that enables to achieve fast and precise forming. One of the most critical steps for achieving high-quality products is researching and developing cemented carbide powders suitable for additive manufacturing. At present, the preparation methods of cemented carbide powders for additive manufacturing are mainly divided into the following four categories: mechanical alloying, spherical WC surface coating technology, spray drying technology and plasma spheroidization technology. These four methods differ in fabrication principle, cost, and flexibility of forming method.Four common preparation methods mentioned above of cemented carbide powders fabricated by AM were reviewed,the physical characteristics and forming properties of the prepared powders were compared, and the principles of powder preparation, their respective advantages and disadvantages, and the suitable additive manufacturing process were analyzed, in order to promote the research and development of cemented carbide powders made by AM.