Design of Ceramic-Metal Composites with Novel Architectures

陶瓷-金属复合材料，或称金属陶瓷，结合了高硬度的陶瓷相和延展性的金属“粘合剂”，广泛用于严重磨损和腐蚀的环境。拟议的研究计划包括继续发展TiC和Ti（C，N）基陶瓷，使用高延展性ni3al基粘结剂合金。在这项工作中提出了两种新的金属陶瓷“结构”：(i)具有纳米到宏观长度尺度的分层结构材料，用于高性能磨损/腐蚀应用；（ii）轻质，控制孔隙形态的材料，用于高能量冲击吸收。******通过将工业金刚石颗粒（总量为0 - 30%）加入到陶瓷微观结构中，并在金属粘合剂中添加石墨烯（占粘合剂体积的0 - 3%），分层陶瓷将大大扩展我们之前的研究。金刚石的加入有望提高金属陶瓷的硬度，从而提高耐磨性，而石墨烯的加入可能会提高粘合剂的屈服应力，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”陶瓷，具有可控的“结构”。其主要目标是制造出能够在压缩中吸收大量能量的超轻、高刚度的细胞材料。为了产生低体积的球形孔隙率（0至40体积%），将使用逸散性淀粉填料（根据我们之前对多孔氧化锆陶瓷的研究）。使用直接发泡技术将产生更高体积分数的球形孔隙，预计可产生高达90%体积%的孔隙率。根据我们最近在氧化铝陶瓷上的合作工作，各向异性孔隙将通过使用冷冻铸造形成。然后多孔绿体将通过反应烧结或熔融渗透致密化。金属陶瓷的表征将包括评估其微观结构、机械和热性能、滑动磨损行为和水腐蚀反应。******作为研究的一个组成部分，几名HQP（包括3名博士级）将接受各种材料加工和分析技术的实践培训，增加他们随后在各种先进工程领域就业的机会。完全可以预期，这项研究将导致大量的出版物，知识传播的机会（例如，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.