Chapter 37. Ductile Intermetallic Toughened Carbide Matrix Composites
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1996 The American Ceramic Society
Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3
How to Cite
Plucknett, K. P., Tiegs, T. N., Becher, P. F., Waters, S. B. and Menchhofer, P. A. (1996) Ductile Intermetallic Toughened Carbide Matrix Composites, in Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314821.ch37
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1996
Print ISBN: 9780470375426
Online ISBN: 9780470314821
Ductile nickel aluminide (Ni3Al) alloys have been used as a ‘binder’ phase for the fabrication of both titanium and tungsten carbide (TIC and WC) matrix composites. Ni3Al alloys exhibit good resistance to aqueous acidic corrosion environments. These alloys are also unusual in that their yield strength increases with temperature, to a maximum at 700–800°C. These properties, combined with high tensile ductilities (up to 50 % strain), make Ni3Al a potentially attractive replacement for Co in cemented carbide fabrication. Materials have been fabricated by both hot-pressing and vacuum-sintering, with Ni3Al contents ranging from 15 to 95 vol. %. Vacuum-sintering cycles were generally similar to those used for the fabrication of WC/Co and TiCN (i.e. Tsint ∼1450–160°C), resulting in sintered densities >95 % of theoretical. WC/Ni3Al materials exhibited an order of magnitude improvement in corrosion resistance over WC/Co, during immersion tests in either sulfuric or nitric acid. These materials also demonstrated improved high temperature strength retention compared to WC/Co cermets, though the initial room temperature strengths were lower. Fracture toughness varied between 8 and 25 MPa.m1/2, and depended primarily upon Ni3Al content and composition.