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Co‐existence of ductile, semi‐ductile, and brittle fractures of polycarbonate
Author(s) -
Chang FengChih,
Chu LineHwa
Publication year - 1992
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1992.070440915
Subject(s) - polycarbonate , materials science , brittleness , composite material , fracture toughness , radius , fracture (geology) , atmospheric temperature range , shear (geology) , elastomer , thermodynamics , physics , computer security , computer science
The ductile–brittle transition behavior of polycarbonate and methylmethacrylate–butadiene–styrene (MBS) elastomer modified polycarbonate has been investigated in terms of notch radius and temperature. At−40°C and 21‐mil notch radius, polycarbonate fractures in three possible modes, ductile (25%), semi‐ductile (50%), and brittle (25%). This semiductile mode fracture has never been reported previously with brittle characterization, but to a greater extent in localized shear yielding on the fracture surface and intermediate toughness. A two‐dimensional fracture mode diagram in terms of temperature and notch radius has been constructed to interpret the observed phenomena. This diagram can also predict the existence of other conditions under which the triplet fracture modes may also occur. Another unstable zone has also been identified where the fracture occurs in either ductile mode or brittle mode over a broad temperature range, instead of the narrow temperature range typically observed for polycarbonate. A model based on the excessive precrack strain just below yielding due to the greater notch radius is proposed to explain such observed semi‐ductile mode fracture.