The Effect of Dislocations and Grain Boundaries on the Electrical Conductivity of Copper Wires

Metals are used daily because of their physical properties like malleability, ductility, and conductivity. They can be found in the components of computers, structure of a skyscraper, and silverware. Scientists have discovered that defects, irregularities in the metal crystal lattice structure, affect the behavior of metals such as their mechanical properties. For this reason, it is important to understand metals at their atomic level. The objective of this project is to explain what occurs to the conductivity of copper metal, when two types of defects (e.g., dislocations and grain boundaries) come in contact. We hypothesize that the conductivity will decrease due to electron scattering. A 2-D model of copper’s crystal lattice structure was developed in a bulletin corkboard using push-pins as the representation of copper atoms in the crystalline structure to explain the conductivity of copper with and without defects. The outreach activity included a copper inductor that was used to measure its resistance with a voltmeter. We created defects in the copper inductor and measured the resistance again to verify that a change had indeed occurred in the copper’s crystal lattice. The model accomplished the desired objective and proved to be an efficient tool for demonstration purposes because of its simplicity and cost effectiveness. The 2-D model was a great way of presenting middle/high students how defects can be beneficial depending on how they are manipulated. This presentation will elucidate results of this project and educational implications in the field will be provided.