Molecular dynamic simulation of a Cu-based shape memory alloy

• Grant number: 15/05494-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2016
• End date: December 31, 2016
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Piter Gargarella
• Grantee: Luís Otávio Zaparoli Falsetti
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Although the martensitic transformation mechanisms of several different shape memory alloys were proposed, they are difficult to testify experimentally because of the fast transformation kinetics. It is still not clear how the nucleation and growth process occurs, i.e. if it occurs at the grain boundaries or at other defects typical of crystalline lattices. Besides this, the effect of thermal and mechanical cycling in the nucleation and growth process or in the formation of different martensite variants are not well understood. The molecular dynamic simulation (MD) method may give evidences for the mechanisms, which could help to develop new shape memory alloys with enhanced properties. By this method, the position and velocity of the different atoms in the system are obtained by numerical solving Newton´s equation of motion. Several physical and mechanical properties as well as dynamical behaviour on the atomistic or macroscopic (grains) scale are obtained using a statistical approach. To perform these simulations, the interatomic potential must be known. Although the interatomic potential for the Cu-Al system was already developed, these alloys were not investigated yet. Considering this, the present work aims to investigate the mechanism of martensitic transformation in a Cu-Al shape memory alloy by means of MD simulations. This system was chosen because their wide applicability as actuators, medical and electromechanical devices. The simulation will use a recently developed interatomic potential. The Cu77Al23 (at%) alloy will be thermal- and mechanical-cycled in order to investigate the mechanisms involved in the transformation.