Diffusional creep and diffusion-controlled dislocation creep and their relation to denuded zones in Mg-ZrH{sub 2} materials
- C.S.I.C., Madrid (Spain). Centro Nacional de Investigaciones Metalurgicas
- Stanford Univ., CA (United States). Dept. of Materials Science and Engineering
- Lawrence Livermore National Lab., CA (United States)
- Univ. of Texas, San Antonio, TX (United States). Div. of Engineering
Langdon`s contention that creep of Mg-0.5 wt% Zr is well characterized by diffusional creep at 400 C is in error. It is shown that Langdon and Gifkins` single analysis of denuded zones formed during creep at 2 MPa, purporting to occur as a result of diffusional creep, in fact, took place in the power-law dislocation creep range where solute atoms are interacting with moving dislocations. This observation supports the earlier conclusions made for creep and denuded zones observed in the hydrided Mg-Zr alloy at 500 C. Furthermore, it is shown that Pickles` data at stresses below 2 MPa at 400 C are not related to diffusional creep as considered by Langdon. In this region, denuded zones appear in both longitudinal and transverse boundaries indicating that grain boundary sliding, accompanied by grain boundary migration, is the principal deformation process. It is proposed that denuded zones are caused by dissolution of precipitates at moving grain boundaries.
- Sponsoring Organization:
- Comision Interministerial de Ciencia y Tecnologia (Spain); USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 619482
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 8 Vol. 38; ISSN 1359-6462; ISSN SCMAF7
- Country of Publication:
- United States
- Language:
- English
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