Design of Ceramic-Metal Composites with Novel Architectures

陶瓷-金属复合材料或金属陶瓷，联合收割机将高硬度陶瓷相与延展性金属“粘合剂”结合，并且广泛用于严重磨损和腐蚀环境中。拟议的研究计划涉及继续发展TiC和Ti（C，N）基金属陶瓷，使用高延展性Ni 3Al基粘结剂合金。在这项工作中提出了两种新的金属陶瓷“架构”：（i）分级结构材料，其组成相在纳米到宏观长度尺度上，用于高性能磨损/腐蚀应用，以及（ii）轻质，可控孔形态材料，用于高能量冲击吸收。通过加入工业金刚石颗粒（0至30体积%），分级金属陶瓷将显著扩展我们先前的研究总计）加入到金属陶瓷微结构中，与金属粘合剂中的石墨烯添加物（0至3体积%）组合的粘合剂体积）。金刚石掺入预计将增加金属陶瓷的硬度，因此，耐磨性，而石墨烯添加可能会提高粘结剂屈服应力和降低摩擦滑动系数。这些改进的特性将显著提高耐磨性。**轻质多孔金属陶瓷将制备成球形和细长孔。这些材料构成了一种全新的“工程”金属陶瓷，具有可控的“结构”。其主要目的是制造超轻，高刚度的蜂窝材料，可以吸收大量的压缩能量。为了产生低体积的球形孔隙率（0至40体积%），将使用短效淀粉填料（遵循我们先前关于多孔氧化锆陶瓷的工作）。使用直接发泡技术将产生更高体积分数的球形孔，预计将产生高达90体积%的球形孔。孔隙率各向异性的孔隙将通过使用冷冻铸造，我们最近的合作工作氧化铝陶瓷。然后通过反应烧结或熔融渗透使多孔绿色体致密化。金属陶瓷的表征将包括其微观结构、机械和热性能、滑动磨损行为和水腐蚀响应的评估。**作为研究的一个组成部分，几个HQP（包括3个博士级）将接受各种材料处理和分析技术的实践培训，提高他们在各种先进工程领域的后续就业机会。完全可以预期，这项研究将产生大量的出版物，知识传播的机会（如国家/国际会议），并有可能产生有价值的知识产权。最终，这些新型材料的成功工业应用有望降低苛刻应用中的维护成本。

Ceramic-metal composites, or cermets, combine a high hardness ceramic phase with a ductile metallic ‘binder', and are widely used in severe wear and corrosion environments. The proposed research programme involves continued development of TiC and Ti(C,N) based cermets, using high ductility Ni3Al-based binder alloys. Two novel cermet ‘architectures' are proposed in this work: (i) hierarchically structured materials, with constituent phases on nano- to macro-length scales, for high performance wear/corrosion applications, and (ii) lightweight, controlled pore morphology materials, for high energy impact absorption.******The hierarchical cermets will significantly extend our prior studies, through incorporation of industrial diamond particles (0 to 30 vol.% in total) into the cermet microstructure, in combination with graphene additions within the metallic binder (0 to 3 vol.% of the binder volume). Diamond incorporation is expected to increase the cermet hardness and, consequently, the wear resistance, while graphene additions will likely raise the binder yield stress and lower the frictional sliding coefficient. These modified characteristics will significantly improve the wear resistance.******The lightweight, porous cermets will be prepared with both spherical and elongated pores. These materials constitute an entirely new class of ‘engineered' cermet, with controlled ‘architectures'. The primary aim is to fabricate ultra-lightweight, high stiffness cellular materials that can absorb significant energy in compression. To generate a low volume of spherical porosity (0 to 40 vol.%), fugitive starch fillers will be used (following our prior work on porous zirconia ceramics). Higher volume fractions of spherical pores will be generated using a direct foaming technique, which is anticipated to create up to 90 vol.% porosity. Anisotropic pores will be formed through the use of freeze-casting, following our recent collaborative work on alumina ceramics. The porous green bodies will then be densified by reaction sintering or melt-infiltration. Cermet characterisation will include assessment of their microstructures, mechanical and thermal properties, sliding wear behaviour, and aqueous corrosion response.******As an integral component of the research, several HQP (including 3 at PhD level) will receive hands-on training in a wide variety of materials processing and analysis techniques, enhancing their opportunities for subsequent employment in a variety of advanced engineering areas. It is fully expected that this research will result in a significant number of publications, opportunities for knowledge dissemination (e.g. national/international conferences), and the potential to generate valuable intellectual property. Ultimately, successful industrial implementation of these novel materials can be expected to lower maintenance costs in demanding applications.