Fabrication of highly porous TiAl 3 intermetallics using titanium hydride as a reactant in the thermal explosion reactio
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ARTICLE Fabrication of highly porous TiAl3 intermetallics using titanium hydride as a reactant in the thermal explosion reaction Xinyang Jiao School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou 221116, People’s Republic of China; and School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People’s Republic of China
Peizhong Feng,a) Yanan Liu, and Xiaoping Cai School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou 221116, People’s Republic of China
Jianzhong Wang State Key Laboratory of Porous Metal Materials, Northwest Institute for Non-ferrous Metal Research, Xian 710016, China
Tomasz Czujko Department of Advanced Materials and Technologies, Faculty of Advanced Technologies and Chemistry, Military University of Technology, Warszawa 00-908, Poland (Received 30 May 2018; accepted 10 July 2018)
Porous TiAl3 intermetallics were synthesized by the thermal explosion (TE) reaction from TiH2–75 at.% Al elemental powders combining with carbamide as the space holder. The results showed that the space holder particles were removed completely by dissolving in water before sintering and the violent exothermic reaction occurred from the temperature of 672–1193 °C within a few seconds. After TE, TiAl3 was the dominant phase in sintered products and the open porosity of 60.8% was obtained without space holder, while the porosity considerably increased to 81.4% with the addition of 60 vol% carbamide particles. The pore-forming mechanism can be concluded as follows: the sphere large pores replicated from carbamide particles and the small pores generated by the TE reaction. Moreover, porous TiAl3 intermetallics possess the excellent oxidation resistance at 650 °C in air, which enabled them good candidate materials for improving the service life and the accuracy of filtration under special conditions. I. INTRODUCTION
Intermetallics have been widely investigated as potential structural and functional materials due to their excellent performances such as low density, high strength, and good oxidation/corrosion resistance at high temperatures.1–3 In general, porous Al-based intermetallics (Ni-, Ti-, Fe-, and Cu-) are well known as materials with good permeability and controllable porosity enabling their applications to be greatly developed in metal filtration, heat insulation, and catalyst supports.4–6 Porous TiAl-based intermetallics possess the common advantages of metals and ceramic alloys due to a mixed character (metallic and covalent) of atomic bonds, their density is less about 50% in comparison to nickel-based alloys and the operating temperature is up to 700–1000 °C.7,8 Several intermetallic compounds such as Ti3Al, TiAl, and TiAl3 are considered as equilibrium phases in the Ti–Al system,2,9 while the TiAl3 compound a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2018.293 J. Mater. Res., 2018
is characterized by the lowest density and highest oxidation r
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