Strain Rate Sensitivity of the Additive Manufacturing Material Scalmalloy®

Abstract

This work investigates the influence of strain rate on the stress/strain behaviour of Scalmalloy. This material is an aluminium–scandium–magnesium alloy, specifically developed for additive manufacturing. The bulk yield stress of the material processed by Selective Laser Melting is approximately 340 MPa which can be increased by heat-treating to approximately 530 MPa. These numbers, combined with the low mass density of 2.7 g/cm3, make Scalmalloy an interesting candidate for lightweight crash-absorbing structures. As this application is inherently dynamic, it is of interest to study the loading rate sensitivity, which is difficult to predict: Al–Sc alloys exhibit classic strain rate sensitivity with an increased yield stress at elevated strain rates. However, Al–Mg alloys are known to show the contrary effect, they exhibit less strength as strain rate is increased. To answer the question how these effects combine, we study the dynamic behaviour at four different strain rates ranging from 10−3 to 1000 /s using servo-hydraulic and split-Hopkinson testing methods. The resulting data is analysed in terms of strain rate sensitivity of tensile strength and failure strain. A constitutive model based on a simplified Johnson–Cook approach is employed to simulate the tensile tests and provides good agreement with the experimental observations.

2D Numerical Simulation of Auxetic Metamaterials Based on Force and Deformation Consistency

“…Both properties are similar to the characteristics of some titanium alloys while featuring a lower mass density. Scalmalloy ® was created as a base for lightweight crash-absorbing structures, specifically for the automotive sector and aerospace engineering [31]. Due to its ductility, it can sustain extensive plastic deformation before failure.…”

“…The corresponding data are provided in Ref. [31]. In this work, a power-law elastoplastic model was employed.…”

Split Hopkinson Tension Bar and Universal Testing Machine for High-Speed X-ray Imaging of Materials under Tension

“…Firstly, a Scandium modified Aluminium-Magnesium alloy AA5028 known as Scalmalloy serves for safety-relevant applications in the filed of crash and impact industry [16]. Specimen preparation and previous works on Scalmalloy can be found in [17,18]. Secondly, a high performance reinforced polymer composite, basalt-fibre reinforced polymer (BFRP) provides good fatigue resistance and energy absorption characteristics.…”

Compression Tests at High Strain Rate on 3D-Printed CuCrZr Alloy Specimens - Material Model Calibration

“…This paper describes the results obtained by quasi-static and dynamic compression tests carried out on 3D-printed CuCrZr specimens produced by L-PBF and the calibration of the most appropriate constitutive materials models performed by means an inverse analytical procedure. Its characterization in dynamic conditions is related to the growing interest in the dynamic behavior of additively manufactured materials in the last years [14][15][16]. Quasi-static tests have been conducted by means of a servo-hydraulic tensile machine, while a direct tension-compression split Hopkinson bar [17] has been used to perform the tests at high strain rate.…”