EFFECT OF STRENGTH ON ENVIRONMENT-ASSISTED CRACKING OF TI-8V-6CR-4MO-4ZR-3AL IN AQUEOUS NACL PART 1 - AGE-HARDENING VS. WORK-HARDENING

Authors
SOMERDAY BP GANGLOFF RP
Citation
Bp. Somerday et Rp. Gangloff, EFFECT OF STRENGTH ON ENVIRONMENT-ASSISTED CRACKING OF TI-8V-6CR-4MO-4ZR-3AL IN AQUEOUS NACL PART 1 - AGE-HARDENING VS. WORK-HARDENING, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 254(1-2), 1998, pp. 166-178
Citations number
34
Categorie Soggetti
Material Science
Journal title
Materials science & engineering. A, Structural materials: properties, microstructure and processing → ACNP
ISSN journal
09215093
Volume
254
Issue
1-2
Year of publication
1998
Pages
166 - 178
Database
ISI
SICI code
0921-5093(1998)254:1-2<166:EOSOEC>2.0.ZU;2-W
Abstract
The objective of this research is to understand the effect of yield st rength on the environment-assisted cracking (EAC) susceptibility of a beta Ti alloy, Ti-8V-6Cr-4Mo-4Zr-3Al (Beta-C), precracked and stressed actively in aqueous NaCl. Isothermal aging renders immune, beta-solut ion treated Beta-C susceptible to severe EAC coincident with strengthe ning by alpha precipitates. The threshold for EAC decreases to 40% of the air fracture toughness, subcritical crack growth rate approaches 1 00 mu m s(-1), and the crack path becomes fully intergranular for agin g times in excess of several hours. In contrast, solution treated and cold-worked single-phase beta Beta-C retains immunity to EAC for simil ar high strengths. For several levels of cold work, Beta-C cracks by t ransgranular microvoid processes, with equal values of EAC threshold s tress intensity and air fracture toughness. Cold work reduces the air fracture toughness of beta-phase Beta-C compared to values for beta/al pha microstructures at similar strengths. The strength increase due to alpha precipitation does not uniquely promote EAC susceptibility. (C) 1998 Published by Elsevier Science S.A. All rights reserved.