ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Tensile experiments in polystyrene (PS) and poly(methyl methacrylate) (PMMA) conducted at constant strain rate over a wide range of pressure and temperature have shown that a brittle-to-ductile transition is induced in these amorphous polymers by the superposition of hydrostatic pressure as well as by the raise of the experimental temperature. A detailed stress-strain analysis permits explanation of the mechanism for the brittle-to-ductile transition in terms of interaction between two competing processes of plastic yielding - crazing and shear banding phenomena. The crazing and shear banding processes respond quite differently to changes of pressure or temperature, causing shifting of the brittle-to-ductile transition point to where the craze initiation stress and shear band initiation stress again become equal. The evidence that the brittle-to-ductile transition pressure becomes lower with increasing temperature refutes a previously suggested concept that the transition relates primarily to mechanical relaxation phenomena.
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1976.070200714
Permalink
