Densification, Microstructure, and Wear Property of In Situ Titanium Nitride-Reinforced Titanium Silicide Matrix Composi
- PDF / 1,437,660 Bytes
- 12 Pages / 593.972 x 792 pts Page_size
- 97 Downloads / 266 Views
THE titanium silicide Ti5Si3 intermetallic compound has been considered recently as a promising candidate material for high-temperature structural applications because of its high melting temperature [2403 K (2130 C)], relatively low density (4.32 g/cm3), capacity to retain high strength up to 1473 K (1200 C), and excellent oxidation and creep resistance.[1,2] Nevertheless, because of its complex hexagonal crystal structure with a low symmetry (D88), the monolithic Ti5Si3 has a considerably low fracture toughness at ambient temperature.[3] Thus, a major challenge for a successful application of Ti5Si3 material is to reduce its roomtemperature brittleness. In this respect, the existing work by Wang et al.,[4] Shon et al.,[5] and Li et al.[6] ascertained that the preparation of ceramic-reinforced Ti5Si3based composites by incorporating the stiffer ceramic phase within Ti5Si3 matrix is an important method to DONGDONG GU, Professor and Alexander von Humboldt Research Fellow, is with the College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, 210016 Nanjing, People’s Republic of China, and is also with the Fraunhofer Institute for Laser Technology ILT/Chair for Laser Technology LLT, RWTH Aachen, D-52074 Aachen, Germany. Contact e-mail: [email protected] CHEN HONG, PhD Candidate, is with the Fraunhofer Institute for Laser Technology ILT/Chair for Laser Technology LLT, RWTH Aachen. GUANGBIN MENG, Graduate Student, is with the College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics. Manuscript submitted March 13, 2011. Article published online September 15, 2011 METALLURGICAL AND MATERIALS TRANSACTIONS A
improve the integrated mechanical properties including fracture toughness. In particular, the development of novel in situ composites, in which the ceramic reinforcements are synthesized in the metallic matrix by chemical reactions between elements, exhibits more significant advantages, e.g., the refined microstructural scale of in situ formed reinforcements, the clean reinforcement/ matrix interfaces with stronger interfacial bonding, and the increased thermodynamic stability and mechanical properties of the composites.[7] In contrast, a reasonable selection of the ceramic reinforcement that is feasible for Ti5Si3 matrix is required. It is known that the coefficient of thermal expansion (CTE) and the elastic modulus are two most important material properties that determine the level of residual stress in composites.[8] Based on the previous studies,[1,2,9] the TiC has been demonstrated to be a suitable candidate material used as the reinforcement for Ti5Si3-based composites because of the similar CTEs (Ti5Si3 9.7 9 107/K vs TiC 7.7 9 107/K). The TiN, which has almost the same CTE (9.4 9 107/K) as that of Ti5Si3, matches even better with Ti5Si3 matrix. Furthermore, the elastic modulus of TiN (250.37 GPa) is considerably lower than that of TiC (439.43 GPa),[10] and normally, the stress of composites can be controlled by using material wit
Data Loading...
