Progress in understanding the high ductility of rare earth B2 (CsCI-type) intermetallics

Title	Progress in understanding the high ductility of rare earth B2 (CsCI-type) intermetallics
Publication Type	Book Chapter
Year of Publication	2008
Authors	Russell AM, Frerichs AE, Gschneidner KA, Biner SB, Chumbley LS, Xie SJ, Williams SH, Chen Q, Becker AT
Editor	Howard SM
Book Title	Epd Congress 2008
City	Warrendale
Publisher	Minerals, Metals & Materials Soc
Pages	587-606
Series Title	Epd Congress
ISBN Number	1079-7580978-0-87339-715
Accession Number	ISI:000255551100068
Keywords	alloys, behavior, COMPOUND AGMG, deformation, ductility, fracture-toughness, INDEPENDENT SLIP SYSTEMS, intermetallics, mechanical properties, mechanical-properties, NIAL SINGLE-CRYSTALS, PLASTIC, rare earth metals, room-temperature, TENSILE DUCTILITY
Abstract	In recent years, several rare earth intermetallic compounds with the B2-type structure have been reported to exhibit high tensile ductility and high K-IC fracture toughness at room temperature. These materials retain considerable ductility even at 77K. These are noteworthy findings because most intermetallics possess poor room temperature ductility and low fracture toughness unless one or more special contrivances are applied (e.g., doping with small additions of interstitial elements, off-stoichiometric compositions, testing in ultra-dry atmospheres, etc.). This paper summarizes recent findings on rare earth B2 intermetallics. These include the determination of the active slip systems; the strain rate sensitivities; yield strength maxima at elevated temperatures; the search for possible twinning and stress-induced phase transformations; ab initio calculations of their defect energies and the anisotropy of dislocation line tension. Potential applications of these materials and the possibilities that this study may suggest strategies for increasing ductility in other intermetallic compounds are discussed.