Molecular dynamics simulations of tensile mechanical properties and microstructures of Al-4.5Cu alloy: the role of temperature and strain rate

Abstract

In this paper, the deformation behavior of Al-4.5Cu alloys containing the Cu clusters under high temperature is systematically investigated by molecular dynamics. Reduced nucleation stress of dislocation is driven by increasing strain rate and temperature, which triggers the stress–strain curves of Al-4.5Cu alloy showing gradually elastic-plastic stage and elastic-plastic-viscous stage. Besides, the defect surface in Al-4.5Cu alloy do not have enough time to move along and gather due to the increase of strain rate, which make the distribution of defect surface mainly divide into three types: the plane distribution which is at 45° angle to the direction of tensile, the stratification distribution which is perpendicular to the direction of tensile and the distribution of honeycomb, respectively. The microscopic fracture morphology for Al-4.5Cu alloy are changed from pure shear fracture to microporous aggregate fracture due to three type of defect surface.