Engineering topics
Dai, Chen
Publications and source records attributed to Dai, Chen.
Processing Techniques for ODS Stainless Steels
Oxide dispersion-strengthened (ODS) alloys have been studied extensively, in part as a response to the need to develop the high-temperature materials that are required for energy efficient systems. ODS stainless steels, in particular, are of technological interest because of their high ductility and high strength at elevated temperatures, which when combined with their resistance to corrosion, render them ideal for many applications that require extreme performance quality. Survey of the published literature reveals that efforts have been devoted to incorporate specific strengthening mechanisms in order to meet demanding performance criteria for ODS alloys. As a result, a number of novel processing approaches have been developed in an effort to design distinct microstructures that can enhance the performance of ODS alloys. In the current paper, various techniques used to manufacture ODS stainless steel alloys are compared and summarized on the basis of a literature search, and results are contrasted with selected experimental data obtained by the authors. In particular, cryomilling, water-atomization, and melt-spinning processes are described in detail as three novel approaches that can be effectively used to distribute nanometric oxides in 316L stainless steel matrix. The microstructural features, mechanical properties, and sintering behavior of the fabricated materials are described and discussed. The critical processing parameters for each processing technique are discussed with reference to the properties of the material. The versatility and potential challenges of the individual techniques are also described and contrasted.
Interfacial characteristics of diamond/aluminum composites with high thermal conductivity fabricated by squeeze-casting method
In this work, aluminum matrix composites reinforced with diamond particles (diamond/aluminum composites) were fabricated by squeeze casting method. The material exhibited a thermal conductivity as high as 613 W / (m · K). The obtained composites were investigated by scanning electron microscope and transmission electron microscope in terms of the (100) and (111) facets of diamond particles. The diamond particles were observed to be homogeneously distributed in the aluminum matrix. The diamond{sub (111)}/Al interface was found to be devoid of reaction products. While at the diamond{sub (100)}/Al interface, large-sized aluminum carbides (Al{sub 4}C{sub 3}) with twin-crystal structure were identified. The interfacial characteristics were believed to be responsible for the excellent thermal conductivity of the material. - Graphical abstract: Display Omitted - Highlights: • Squeeze casting method was introduced to fabricate diamond/Al composite. • Sound interfacial bonding with excellent thermal conductivity was produced. • Diamond{sub (111)}/ aluminum interface was firstly characterized by TEM/HRTEM. • Physical combination was the controlling bonding for diamond{sub (111)}/aluminum. • The growth mechanism of Al{sub 4}C{sub 3} was analyzed by crystallography theory.