Mechanical properties and energy absorption capability improvement of Ti-6Al-4V porous materials through porous structure design optimization

The structural materials, which exhibit high toughness and high strain energy absorption, can be used in impact-resistant applications such as bulletproof vests, automobiles, and aerospace. Numerous studies indicate that functional gradient materials, which contain non-uniform density, exhibit excellent performance in energy absorption. During the compression test, the struts of the gradient porosity materials collapsed layer by layer, and this phenomenon optimizes the energy absorption capability of the materials. Furthermore, the collapse region or direction can be predicted and controlled by the design of the gradient porosity materials. In addition to the above concepts, this research also improves its energy absorption capacity through the following two strategies: (1) Chamfering the node of the porous structure to avoid the stress concentration, and (2) optimizing the angle between the struts of the porous material to enhance the ductility of the material. To fabricate the complicated gradient porosity structure, the structural materials were printed using the selective laser melting process with Ti-6Al-4V ELI alloys. Through the experiments conducted in this study, the structural strength was enhanced by up to 28% through structure design, and the energy absorption was improved by 19% compared to the gyroid structure, which has been reported to exhibit good energy absorption capabilities.