Studies on Tensile Properties and Fracture Behavior of Al-6Si-0.5Mg (-Cu or/and Ni) Alloys at Various Strain Rates

摘要

The aim of this paper is to evaluate the effects of various strain rates on the tensile properties of Al-6Si-0.5Mg cast alloys with Cu or/and Ni additions and to establish data on the stress-strain behavior of the alloys with applications in automotive engineering. Experimental alloys of the following composition were prepared by melt processing technique. Both microstructure and the mechanical properties were investigated. The uniaxial tension test was carried out at strain rates ranging from 10~(-4)s~(-1) to 10~(-2)s~(-1). Tensile strengths were found to increase with ageing temperature and the maximum being attained at peak age condition (lhr at 225°C). The additions of Cu or/and Ni resulted in an increase in tensile strength and 2wt% Cu content alloy (Al-6Si-0.5Mg-2Cu) showed maximum strength. Evaluation of tensile properties at three strain rates (10~(-4), 10~(-3) and 10~(-2)s~(-1)) showed that strain rates affected the tensile properties significantly. At higher strain rates the strength was better but ductility was poor.