Creep prior to stress corrosion cracking (SCC) has been frequently observed. Externally imposed anodic dissolution currents increase creep rates of pure metals and alloys in environments that do not cause SCC. Creep prior to SCC may result from anodic currents at active film rupture sites caused by coupling to surrounding noble passive surfaces. Several investigators have recently shown a correlation between creep rate and time to failure by SCC, implying that mechanisms of creep and cracking may be related. Recent thin-film diffusion experiments have shown evidence of vacancy formation at anodically dissolving copper surfaces. Anodically generated vacancies may increase creep by stimulating dislocation climb, as does elevated temperature during thermal creep or by attraction to dislocation cores. This paper reviews this and other information leading to a proposed SCC mechanism describing anodic attenuation of strain hardening, localized surface plasticity (LSP), crack initiation, and crack-tip embrittlement by anodic dissolution at film rupture sites.

Subject
Film rupture, Dislocation, Metal surfaces, Crack initiation, Anode surfaces, Vacancies, Stress, Anodic dissolution, Anodic current, Creep, Slip, Plasticity, Stress corrosion cracking
Keywords:
stress corrosion cracking, anodic dissolution, film rupture, surface plasticity, strain hardening, cleavage, vacancies, dislocations, slip, atomic bond weakening
© 1995 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1995
Association for Materials Protection and Performance (AMPP)
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