Tension-compression asymmetry of additively manufactured Maraging steel

Additive Manufacturing (AM) or 3D printing refers to processes used to synthesize an engineering part, where successive layers of material are formed under computer control to create a three-dimensional object. AM methods allow for production of parts with complex geometries and exceptional properties, which is of particular interest of automotive, aerospace, marine, and defence industries. Most of the parts produced for these applications are non-critical, however applications involving large deformations, such as impact, are of serious interest to industry. Unlike most conventional materials, AM metals do not have the same compressive and tensile behavior. This paper presents a preliminary study of experimental results of the tensile and compressive behaviour of additively manufactured Maraging Steel (MS1) using Digital Image Correlation (DIC) technique. Compression and tension samples in the form of cubes and rods were prepared using Direct Metal Laser Sintering (DMLS) technique through an EOS M290 machine. Compression data was collected using a DIC system to investigate the anisotropy of the strain field in the material. Results showed some material anisotropy due to build direction and dramatic improvement in elongation to failure in compression. Finally, a tension-compression asymmetry analysis of the additively manufactured MS1 revealed that the extreme softening in tension is not a result of void nucleation/growth in the material, but rather geometric softening due to necking.