Perspective on the Bond Bending and Bond Stretching Effects at the Atomic Scale and Their Relationship to Ductile Versus Brittle Materials Failure

Abstract

The two bonding mechanisms for the elements of the Periodic Table are defined. These are for the standard bond stretching effect and for a newly recognized and developed bond bending-bond shearing effect. This work involves the interpretation, definition and utilization for the bond bending-bond shearing function at the atomic bonding scale. Section 2 provides the relevant information. The solids forming elements of the Periodic Table are used to form the complete spectrum of the related properties needed for the ductile versus brittle assessments. The Poisson's ratios for these pure materials forms have the prime role in the methodology that is developed. A particular value of the ratio of the bond bending-bond shearing property to the bond stretching property is shown to divide the elements into their separate ductile and brittle groupings for the state of uniaxial tension. It is found that the numbers of elements in each group, ductile vs. brittle, are in approximate balance. The most ductile elements are gold, lead and thallium while the most extreme brittle element is beryllium.