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Title: Strengthening mechanism of high strength titanium alloys. Technical report Dec 1969--Dec 1970. [Ti--5. 25--Al--5. 5V--0. 9Fe--0. 5Cu]

Abstract

The investigation to relate fracture toughness, void formation and growth and ductility to microstructural features in an alpha--beta alloy, Ti--5.25Al--5.5V--0.9Fe--0.5Cu continued. New data confirm the earlier reported relationships between fracture toughness and microstructure of both equiaxed alpha and Widmanstatten plus grain boundary in aged beta matrix morphologies. In equiaxed alpha structures, fracture toughness depends linearly upon the grain boundary area per unit volume, S/sub V/, and is independent of equiaxed alpha particle size or spacing. In a grain boundary alpha structure, fracture toughness depends both on S/sub V/ and, within limits, linearly on the thickness of the grain boundary alpha. Equations relating tensile void growth rates to microstructure for both morphologies have been derived. Tensile fracture is shown to be intergranular in nature and occurs when a critical crack length--stress relationship is satisfied. The amount of ductility achievable in a specimen depends upon the rate of void growth. If the growth rate is rapid, the crack reaches a critical size for fracture at a lower applied stress and strain and hence the ductility is less. A mechanism for void growth at alpha--beta interfaces is presented which accounts for the higher frequency of voids at 30--70 degrees to the tensile axis.more » An explanation is offered to the apparently contradictory behavior in which grain boundary alpha improved fracture toughness but lowers tensile ductility. (auth)« less

Authors:
;
Publication Date:
Research Org.:
Snell (Forster D.), Inc., Florham Park, NJ (USA)
OSTI Identifier:
7293554
Report Number(s):
AD-884785
DOE Contract Number:  
F33615-70-C-1297
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM ALLOYS; FRACTURE PROPERTIES; MICROSTRUCTURE; TITANIUM BASE ALLOYS; VANADIUM ALLOYS; COPPER ADDITIONS; CRYSTAL DEFECTS; DUCTILITY; IRON ADDITIONS; TITANIUM-ALPHA; TITANIUM-BETA; VOIDS; ALLOYS; COPPER ALLOYS; CRYSTAL STRUCTURE; ELEMENTS; IRON ALLOYS; MECHANICAL PROPERTIES; METALS; TENSILE PROPERTIES; TITANIUM; TITANIUM ALLOYS; TRANSITION ELEMENTS; 360103* - Metals & Alloys- Mechanical Properties; 360102 - Metals & Alloys- Structure & Phase Studies

Citation Formats

Greenfield, M A, and Margolin, H. Strengthening mechanism of high strength titanium alloys. Technical report Dec 1969--Dec 1970. [Ti--5. 25--Al--5. 5V--0. 9Fe--0. 5Cu]. United States: N. p., 1971. Web.
Greenfield, M A, & Margolin, H. Strengthening mechanism of high strength titanium alloys. Technical report Dec 1969--Dec 1970. [Ti--5. 25--Al--5. 5V--0. 9Fe--0. 5Cu]. United States.
Greenfield, M A, and Margolin, H. 1971. "Strengthening mechanism of high strength titanium alloys. Technical report Dec 1969--Dec 1970. [Ti--5. 25--Al--5. 5V--0. 9Fe--0. 5Cu]". United States.
@article{osti_7293554,
title = {Strengthening mechanism of high strength titanium alloys. Technical report Dec 1969--Dec 1970. [Ti--5. 25--Al--5. 5V--0. 9Fe--0. 5Cu]},
author = {Greenfield, M A and Margolin, H},
abstractNote = {The investigation to relate fracture toughness, void formation and growth and ductility to microstructural features in an alpha--beta alloy, Ti--5.25Al--5.5V--0.9Fe--0.5Cu continued. New data confirm the earlier reported relationships between fracture toughness and microstructure of both equiaxed alpha and Widmanstatten plus grain boundary in aged beta matrix morphologies. In equiaxed alpha structures, fracture toughness depends linearly upon the grain boundary area per unit volume, S/sub V/, and is independent of equiaxed alpha particle size or spacing. In a grain boundary alpha structure, fracture toughness depends both on S/sub V/ and, within limits, linearly on the thickness of the grain boundary alpha. Equations relating tensile void growth rates to microstructure for both morphologies have been derived. Tensile fracture is shown to be intergranular in nature and occurs when a critical crack length--stress relationship is satisfied. The amount of ductility achievable in a specimen depends upon the rate of void growth. If the growth rate is rapid, the crack reaches a critical size for fracture at a lower applied stress and strain and hence the ductility is less. A mechanism for void growth at alpha--beta interfaces is presented which accounts for the higher frequency of voids at 30--70 degrees to the tensile axis. An explanation is offered to the apparently contradictory behavior in which grain boundary alpha improved fracture toughness but lowers tensile ductility. (auth)},
doi = {},
url = {https://www.osti.gov/biblio/7293554}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1971},
month = {3}
}

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