Laves phase intermetallic matrix composite in situ toughened by ductile precipitates. (November 2017)

• Record Type: Journal Article
• Authors: Knowles, Alexander J; Bhowmik, Ayan; Purkayastha, Surajit; Jones, Nicholas G; Giuliani, Finn; Clegg, William J; Dye, David; Stone, Howard J
• Is Part Of: Scripta materialia. Number 140(2017)
• Page Start: 59
• Page End: 62
• Publication Date: 2017-11
• Subjects: Intermetallics -- Composites -- Precipitation -- Orientation relationship -- Mechanical properties; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2017.06.043
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: Laves phase based materials are of interest for elevated temperature applications for their high melting points and strengths but are critically limited by their low fracture toughness. Here, a Laves phase intermetallic matrix composite toughened by ductile precipitates has been studied. This microstructure was produced in situ by heat treating a Fe2 (Mo, Ti) based alloy to precipitate ∼ 12% volume fraction of fine ∼ 250 nm bcc, A2 (Mo, Ti), phase, with an orientation relationship of [ 100 ] C 14 / / [ 113 ] A 2, [ 010 ] C 14 / / [ 1 1 ¯ 1 ¯ ] A 2, [ 001 ] C 14 / / [ 12 1 ¯ ] A 2 . The precipitated A2 phase increased the indentation fracture toughness from 1.1 to 2.2 MPa m 1/2 while maintaining a high hardness of HV 0.5 = 8.9 GPa similar to monolithic Laves phases. Graphical Abstract: Laves phase intermetallic matrix composite toughened by ductile precipitates: (a) microhardness indent with corner cracking demonstrating (b) crack deflection, (c) crack bridging and (d) necking and pullout, resulting in (e) an improved K C ( HV ) with comparison to other Laves phase materials, adapted from Zhu et al. (1999).