On the Mechanism of Ductile Bending in Ionic Crystals PDF Download

Author: Charles E. May
Publisher:
ISBN:
Category : Bending
Languages : en
Pages : 24

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Book Description
This report presents experimental evidence in support of a mechanism that explains the bending of face-centered cubic ionic single crystals such as sodium chloride. When a specimen is deformed in flexure, some new dislocations are generated while others are driven from the sample; some of the remaining dislocation align themselves along the (110) slip planes to produce "orientation" domain boundaries perpendicular to the slip planes. This type of process is generally referred to as mechanical polygonization. The existence of orientation domains was confirmed by an X-ray diffraction technique. The number of domains increases with increasing deflection, and there is slight evidence that the average angle between adjacent domains may also increase with increasing deflection. An approximate value for the average angle attained between adjacent domains is about 1/4°. Observation of curvature of the fracture faces also lends support to the correctness of the model. A unique relaxation phenomenon appears to occur if a crystal is allowed to sit with a constant overall deflection; the curvature that is present apparently tends to become more uniform along the length of the specimen.