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The Portevin-Le Chatelier (PLC) phenomenon or dynamic strain ageing results from the interaction between dislocations and solute atoms supersaturating a solid solution and presents itself as serrations in the stress-strain curves upon plastic tensile deformation of Al-Mg alloys. This research focuses on the study of the phenomenon when NbB2 nanoparticles are present in a magnesium-supersatured Al matrix, with different levels of Mg. The nanoparticles were obtained by fragmentation in a high energy ball mill, and were then mixed with aluminum powder to obtain Al–NbB2 nanocomposite pellets that were later added to an Al-Mg melt. This was cast into rods that were cold-rolled into 1mm diameter wires. The wires were solution treated and water-quenched. The tensile tests were conducted with rates of 0.125, 0.250 and 0.500 mm/min. As expected, the phenomenon was observable as the material entered the plastic region of the stress-strain curves. The NbB2 nanoparticles affected the phenomenon, causing a reduction of the serrated signal amplitude. Also, it was found that a reduction in the Mg content caused a decrease in the serrated signal amplitude.
Author(s):
Michelle Marrero-Garcia
Mechanical Engineering
University of Puerto Rico - Mayaguez
United States
Angelisse Ramos-Morales
Civil Engineering
University of Puerto Rico - Mayaguez
United States
David Florian-Algarin
Civil Engineering
University of Puerto Rico - Mayaguez
United States
Oscar Marcelo Suarez
Engineering Science and Materials
University of Puerto Rico - Mayaguez
United States