The Influence of Ni-Coated TiC on Laser-Deposited IN625 Metal Matrix Composites
- PDF / 588,161 Bytes
- 6 Pages / 593.972 x 792 pts Page_size
- 84 Downloads / 172 Views
icle-reinforced metallic matrix composites (MMCs) are of interest in many applications due to their multifunctionality, which yields combinations of properties, such as high specific strength, stiffness, and toughness, and a low coefficient of thermal expansion, that are unachievable with conventional materials.[1] Ni-based MMCs with ceramic reinforcements are used in a wide range of industrial operations with cutting, rolling, pelletizing, stamping, piercing, drawing, punching, etc.[2] Various synthesis methods, including casting and powder metallurgy techniques, have been used for conventional manufacturing of MMCs.[3,4] The presence of undesirable interfacial reactions and particle segregation represents two key issues that have limited the use of casting methods, partially due to an extended contact time between ceramic particles and the molten
BAOLONG ZHENG, Postdoctoral Researcher, TROY TOPPING, Postdoctoral Candidate, YIZHANG ZHOU, Associate Researcher, and ENRIQUE J. LAVERNIA, Provost and Executive Vice Chancellor, are with the Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616. Contact e-mail: [email protected] JOHN E. SMUGERESKY, Senior Staff Member, is with Sandia National Laboratories, Livermore, CA 94551-0969. ASIT BISWAS, Research Manager, and DEAN BAKER, CEO, are with Advanced Powder Solutions, Inc., Cypress, TX 77429. Manuscript submitted September 24, 2009. Article published online January 9, 2010 568—VOLUME 41A, MARCH 2010
metal and density differences between ceramic and metals. In contrast, whereas conventional powder metallurgical routes avoid the presence of a liquid phase, these are relatively complex processes frequently limited in terms of product geometry. The LENS* process, *LENS is a trademark of Sandia National Laboratories, Albuquerque, NM.
incorporating features from stereolithography and laser cladding, is a laser-assisted direct metal manufacturing process that provides a pathway to produce net-shaped components from a three-dimensional (3-D) computeraided design file.[5] The primary advantages associated with LENS are the following: a small heat affected zone with high cooling rate resulting in fine microstructures; easy gradient deposition of multiple materials within a single component; and fully dense near-net-shape metal components. However, only spherical powders with diameters of 36 to 150 lm are recommended for use in LENS processing.[6] Thus, optimization of the LENS requires fundamental study of the influence of fine and irregular shaped ceramics particles in the case of MMCs. The strength and stability of the interfacial region between the reinforcement particles and metal matrix govern the mechanical properties of MMCs, and extensive efforts have been devoted to understanding and manipulating the interfacial behavior in MMCs. In the case of metal-ceramic MMCs, it is often desirable to promote wettability while simultaneously avoiding undesirable interfacial reactions. One strategy that has been implemented is to coat the reinforceme
Data Loading...
