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Title: Cohesive-length scales for damage and toughening mechanisms

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Alternate Identifier(s):
OSTI ID: 1245029
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Resource Type:
Journal Article: Published Article
Journal Name:
International Journal of Solids and Structures
Additional Journal Information:
Journal Volume: 55; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-07-05 05:57:48; Journal ID: ISSN 0020-7683
Country of Publication:
United States

Citation Formats

Sills, R. B., and Thouless, M. D. Cohesive-length scales for damage and toughening mechanisms. United States: N. p., 2015. Web. doi:10.1016/j.ijsolstr.2014.06.010.
Sills, R. B., & Thouless, M. D. Cohesive-length scales for damage and toughening mechanisms. United States. doi:10.1016/j.ijsolstr.2014.06.010.
Sills, R. B., and Thouless, M. D. 2015. "Cohesive-length scales for damage and toughening mechanisms". United States. doi:10.1016/j.ijsolstr.2014.06.010.
title = {Cohesive-length scales for damage and toughening mechanisms},
author = {Sills, R. B. and Thouless, M. D.},
abstractNote = {},
doi = {10.1016/j.ijsolstr.2014.06.010},
journal = {International Journal of Solids and Structures},
number = C,
volume = 55,
place = {United States},
year = 2015,
month = 3

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.ijsolstr.2014.06.010

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Cited by: 7works
Citation information provided by
Web of Science

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  • Abstract not provided.
  • The relevant toughening mechanisms in two-phase titanium aluminides are reviewed in order to elucidate microstructure/fracture toughness relationships. Both intrinsic and extrinsic toughening mechanisms are present in Ti[sub 3]Al- and TiAl-base alloys. The former affects the initiation toughness (i.e., K[sub Ic] value) at the onset of crack extension, while the latter leads to crack growth toughness by instigating a resistance-curve behavior. Intrinsic toughening arises from matrix slip and ductile-phase blunting. In contrast, extrinsic toughening originates from crack deflection, ductile-phase bridging, shear ligament toughening, microcrack shielding, twin toughening, and the growing crack singularity. The influence of microstructure on toughening mechanisms in two-phasemore » Ti[sub 3]Al- and TiAl-base alloys is discussed, with particular emphasis on the need to control the microstructure in order to achieve the desired mechanical properties.« less
  • Many intermetallic compounds offer an attractive combination of properties for either high-temperature structural applications or low-temperature corrosion resistance. Nevertheless, commercial exploitation of these compounds has been hampered by lack of adequate ductility, formability, and/or fracture toughness. In many cases, these problems are exacerbated by aggressive environments, such as oxygen or hydrogen. Methods for improving toughness in both inert and aggressive environments are discussed in this review. Techniques described include crystal structure modification, microalloying, control of grain size or shape, reinforcement by ductile fibers or particles, and control of substructure. The limitations of each of these techniques are described.
  • The mechanisms of toughening in an intermetallic matrix composite were determined by FRASTA, a technique that reconstructs microfailure details of a fracture event by comparing the topographies of conjugate fracture surfaces. Graphic portrayals of the interaction of a crack front with microstructure features are presented for a forged gamma titanium aluminide reinforced with 20 vol%, 300-[mu]m-diameter, 30-[mu]m-thick TiCb platelets. The threefold toughness increase relative to unreinforced material is attributed to (1) drag on the crack front by the TiCb platelets, (2) bridging of the crack faces by the TiCb platelets, and (3) deflection of the crack front by microcracks inmore » the process zone that nucleate and grow out-of-plane at TiCb platelets. The fractographic results explain discrepancies between measured and predicted toughnesses, provide the mechanistic understanding and microfailure data needed to develop more reliable models, and suggest microstructural modifications for developing more fracture-resistant materials.« less