RESUMO
Aluminum metal matrix composites are potential materials for aerospace and automobile industrial applications due to their enhanced mechanical and tribological properties. Aluminum reinforced with silicon carbide particles has been developed with enhanced mechanical and tribological behavior, but it lacks wettability between matrix and reinforcement causing weak bonding, which reduces the degree of enhancement. The objectives of this study were to fabricate aluminum-based metal matrix composites with enhanced wettability at varying stirring speeds (350, 450, 550 rpm), stirring time (5, 10, 15 min), weight percentage of SiC (0, 5, 10 wt.%), and weight percentage of MoS2 (0, 2, 4 wt.%). Nine samples were fabricated using stir casting based on Taguchi L9 orthogonal array. Hardness, tensile strength, and wear rate of the developed composite were investigated and analyzed as a single response characteristic using Taguchi's signal-to-noise ratio and as a multi-response characteristic using hybrid Taguchi-grey relational analysis (HTGRA). The results revealed that the addition of SiC in the composite produced better hardness, tensile strength, and wear rate. The addition of MoS2 in the composite showed better hardness and tensile strength only up to 2 wt.% of MoS2, and in the case of wear rate, the addition of MoS2 in the composite up to 4% showed better wear resistance. Al-SiC-MoS2 hybrid composite shows better enhancement in hardness, tensile strength, and wear resistance than the Al-SiC composite.
RESUMO
4D printed objects are indexed under additive manufacturing (AM) objects. The 4D printed materials are stimulus-responsive and have shape-changing features. However, the manufacturing of such objects is still a challenging task. For this, the designing space has to be explored in the initial stages, which is lagging so far. This paper encompasses two recent approaches to explore the conceptual design of 4D printed objects in detail: (a) an application-based modeling and simulation approach for phytomimetic structures and (b) a voxel-based modeling and simulation approach. The voxel-based modeling and simulation approach has the enhanced features for the rapid testing (prior to moving into design procedures) of the given distribution of such 4D printed smart materials (SMs) while checking for behaviors, particularly when these intelligent materials are exposed to a stimulus. The voxel-based modeling and simulation approach is further modified using bi-exponential expressions to encode the time-dependent behavior of the bio-inspired 4D printed materials. The shape-changing materials are inspired from biological objects, such as flowers, which are temperature-sensitive or touch-sensitive, and can be 4D printed in such a way that they are encrypted with a decentralized, anisotropic enlargement feature under a restrained alignment of cellulose fibers as in the case of composite hydrogels. Such plant-inspired architectures can change shapes when immersed in water. This paper also outlines a review of the 4D printing of (a) smart photocurable and biocompatible scaffolds with renewable plant oils, which can be a better alternative to traditional polyethylene glycol diacrylate (PEGDA) to support human bone marrow mesenchymal stem cells (hMSCs), and (b) a biomimetic dual shape-changing tube having applications in biomedical engineering as a bioimplant. The future applications would be based on these smart and intelligent materials; thus, it is important to modify the existing voxel-based modeling and simulation approach and discuss efficient printing methods to fabricate such bio-inspired materials.
