Materials Science and Engineering A276 (2000) 58 – 69 Design and tailoring of Ni–Sn–W composites for bonded abrasive applications Galina L. Kourtoukova a,1 , Chrysanthe Demetry a, *, S. Ramanath b , Richard M. Andrews b , David S. Jacobs b , Ronald R. Biederman a a Materials Science and Engineering Program, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609 -2280, USA b Saint -Gobain /Norton Company, Worcester, MA 01615, USA Received 21 January 1999; received in revised form 8 July 1999 Abstract The combination of properties ideal for metal bonds in abrasive products can rarely be achieved in a monolithic material. This research demonstrates a successful approach for producing a composite bond with higher elastic modulus without a significant increase in wear resistance, by taking advantage of the reaction between matrix and reinforcement to produce intermetallics. Composites comprised of a Ni–Sn matrix with continuous W fiber and/or W powder dispersoid were prepared by powder metallurgy methods. Composite specimens densified by hot pressing were characterized with a combination of scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses, measurements of wear resistance, and measurements of Young’s modulus and hardness by both bulk and nanoindentation methods. A significant stiffening effect was observed; the elastic modulus of the composites was up to 30% greater than that predicted by a rule of mixtures based on the moduli of the unreacted fiber and matrix constituents alone. As desired, the wear resistance of the composite was approximately equal to that of the Ni – Sn matrix. One contribution to this combination of properties is believed to be the high elastic moduli and likely low fracture toughness of the Ni–W and Ni–Sn intermetallics that are formed. Properties of the Ni–Sn–W composites are contrasted with those of a Ni–Sn matrix reinforced with WC particulate, where no reaction occurs at the interface. © 2000 Elsevier Science S.A. All rights reserved. Keywords: Nickel – tungsten composites; Tungsten fibers; Nickel – tungsten intermetallics; Nickel – tin intermetallics; Elastic modulus; Wear resistance www.elsevier.com/locate/msea 1. Introduction Metal-bonded superabrasives (e.g. containing dia- mond or cubic boron nitride abrasive grains) are often the optimum choice for grinding very hard materials such as cemented carbides, concrete and granite, glass, and a variety of other non-ferrous and ferrous materials [1,2]. For many high precision cutting applications, there is a need for very thin, stiff grinding wheels and thus bonds with higher elastic moduli than the conven- tional bronze-based bonds. However, many other prop- erties, particularly wear resistance, also determine the performance of a metal bond. For a bond with rela- tively low wear resistance, the full cutting ability of the abrasive is not utilized before the supporting bond wears away. For a bond with a relatively high wear resistance, wear flats on the abrasive may develop while still firmly held in the bond, preventing self-sharpening and resulting in increased grinding forces and poor surface finish. Many high melting point metals and ceramics have the high elastic modulus desired for the bond material, but they tend to have high hardness and high wear resistance. Thus, a monolithic bond material is not likely to possess the combination of properties necessary for optimum performance. This research investigated a powder metallurgy-based composites approach as a means of increasing elastic modulus without significantly increasing wear resis- * Corresponding author. Tel.: +1-508-8315195; fax: +1-508- 8315178. E-mail address: cdemetry@wpi.edu (C. Demetry) 1 Completed in partial fulfillment of the requirements for the degree of Master’s of Science in Materials Science and Engineering at Worcester Polytechnic Institute. 0921-5093/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved. PII:S0921-5093(99)00516-X