Evaluation of Johnson-Cook constitutive material model parameters for additively manufactured AlSi10Mg alloy test specimens

Abstract

Additive manufacturing techniques are widely employed in the automobile sector for making lightweight components that are used as energy absorbers during the crash. An exact calculation of the flow behavior of metals considering the collective influence of strain, strain rate, and temperature is vital for understanding the crashworthiness of the additively manufactured(AM) components. It is important to estimate the strain dependency of the additive AlSi10Mg alloy material as an initial step to quantify the flow behavior of metals. In this connection, dog bone-shaped specimens were prepared based on the ASTM E8M-04 standard from the AlSi10Mg printed specimen at 0°, 45°, and 90° concerning the printing direction. Both as-built and heat-treated specimens were investigated, and the stress–strain curves were plotted. The constants A, B, and n in the Johnson-Cook (J-C)material model are derived from the stress–strain curves in terms of strain dependency. The yield stress for the as-built material is about 350 MPa which was increased by heat-treatment to about 550 MPa. Based on the experimental results, the Johnson-Cook model constants A, B, n, and C were established for the AlSi10Mg alloy. A constitutive model based on the J-C approach is employed to simulate the tensile test specimen which provides good agreement with the experimental observations.