The present research deals with development and characterisation of magnesium–SiC–Gr hybrid composites through powder metallurgy route. Morphology analysis of the magnesium and reinforcement powder particles has been carried out using particle size analyser (PSA) and X-ray diffraction (XRD), and then the mixed powders were analysed through scanning electron microscope (SEM). The developed composite exhibit increased hardness when compared to base material, which could be attributed to the presence of hard SiC. Furthermore, a slight decrease in hardness is observed for the hybrid composite when compared to Mg–SiC composite due to the presence of soft Gr particles. The tribological properties of the developed composite materials were investigated using pin-on-disc wear test apparatus under dry sliding conditions. The wear resistance of the developed composites improved significantly than that of the magnesium matrix due to the upright effect offered by both of the reinforcements. The SEM analysis was carried out on the worn out surfaces for better understanding of wear mechanisms. 5% Gr reinforced Mg-10SiC composites confer better wear resistance among the developed composites

A novel epoxy-based composites were fabricated by reinforcing pineapple/flax (PF) fibers and peanut oil cake (PCF) filler using the hand layup cum compression moulding technique and investigated its mechanical, water absorption and wear properties as a function of wt.% of PF fibers (20–40 wt.%) and PCF (1–3 wt.%). The XRD and FTIR results proved the presence of lignocellulosic nature in PCF. Mechanical test results showed significant enhancement in the properties after the addition of PCF. The maximum tensile, flexural and impact properties of 37. 89 MPa, 70.28 MPa and 96.99 J/m were observed in the composites having 20 wt.% of PF and 2 wt.% of PCF. Taguchi based optimization observed a lower specific wear rate (SWR) with 2 wt.% PCF/20 wt.% PF/5 N load and 1500 m sliding distance (SD) combination. The ANOVA results proved the significance of PCF, PF fiber, sliding distance, and load for SWR in this experimentation. The Taguchi optimized results observed a lower coefficient of friction (COF) in 2 wt.% PCF/20 wt.% PF/5N load/500 m SD combination. SEM results displayed surface deformations in the wear-tested composites.

The additive manufacturing technique of material extrusion has challenge of excessive process defects and not achieving the desired mechanical properties. The industry is trying to develop certification to better control variations in mechanical attributes. The current study is a progress towards understanding the evolution of processing defects and the correlation of mechanical behavior with the process parameters. Modeling of the 3D printing process parameters such as layer thickness, printing speed, and printing temperature is carried out through L27 orthogonal array using Taguchi approach. In addition, CRITIC embedded WASPAS is adopted to optimize the parts' mechanical attributes and overcome the defects. Flexural and tensile poly-lactic acid specimens are printed according to ASTM standards D790 and D638, respectively, and thoroughly analyzed based on the surface morphological analysis to characterize defects. The parametric significance analysis is carried out to explore process science where the layer thickness, print speed, and temperature significantly control the quality and strength of the parts. Mathematical optimization results based on composite desirability show that layer thickness of 0.1 mm, printing speed of 60 mm/s, and printing temperature of 200 °C produce significantly desirable results. The validation experiments yielded the maximum flexural strength of 78.52 MPa, the maximum ultimate tensile strength of 45.52 MPa, and maximum impact strength of 6.21 kJ/m². It is established that multiple fused layers restricted the propagation of cracks with minimum thickness due to enhanced diffusion between the layers.