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An Overview of the Strengthening of Glass Fibers by Surface Stress Relaxation
Author(s) -
Lezzi Peter J.,
Tomozawa Minoru
Publication year - 2015
Publication title -
international journal of applied glass science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 34
eISSN - 2041-1294
pISSN - 2041-1286
DOI - 10.1111/ijag.12108
Subject(s) - materials science , composite material , glass fiber , soda lime , glass transition , ultimate tensile strength , relaxation (psychology) , stress (linguistics) , fiber , compressive strength , stress relaxation , silicate glass , surface stress , silica glass , oxide , polymer , metallurgy , creep , psychology , social psychology , linguistics , philosophy , surface energy
Pristine glass fiber is well known to become mechanically weaker when heat‐treated in the presence of water vapor. However, recently, the same fiber was found to become stronger if heat‐treated while held under a subcritical tensile stress at a temperature below the glass transition temperature. The added strength was attributed to the formation of a surface compressive layer on the glass created by a surface stress relaxation process that occurred while being held under the tensile stress in air. Silica glass fibers with strengths estimated to be ~7–8 GP a were produced, exceeding the ~5.5 GP a strength of fresh optical fiber commonly reported at room temperature in air. Similar degrees of strengthening, a 20–30% improvement, have been observed previously for E ‐glass and is reported here for the first time for soda‐lime silicate glasses. This process is a new glass strenthening method that may be applied to all oxide glasses and is not subject to the same constraints as currently available methods.