Predictive and experimental analysis of fracture toughness and density in green aluminum powder compacts: A Taguchi DOE approach

In this paper, we studied the effects of two processing parameters (mass and compaction pressure) on the mode I fracture toughness (KIC) and relative density (RD) of green aluminum powder compacts. The effects of these factors were modeled and optimized using Taguchi design of experiment (DOE). Several complex mathematical models and finite element modeling software have been used to study the responses of K IC and RD in metal powder compacts to variations in compaction pressure and/or powder mass. Taguchi DOE is a robust, user-friendly statistical and modeling tool that is easier to use than most approaches for modeling the behavior of aluminum powder compacts. The L 16 orthogonal array was chosen for the 2-factor and 4-level experiment. The mass of the powder was varied from 3.5 to 5 g while the compaction pressures used were 288.9, 333.4, 377.8, and 422.3 MPa. Results showed that the best combination of factors, yielding an optimal RD of 91%, was 3.5 g of powder and 422.3 MPa of compaction pressure. The optimal K IC of 0.756 MPa · m0.5 was attained at the same conditions. These improvements are directly linked to enhanced particle deformation, reduced interparticle voids (<20 μm), and improved interparticle bonding at higher compaction pressures, as evidenced by SEM micrographs of fracture surfaces. Although the ANOVA showed that compaction pressure significantly affected the KIC and RD of aluminum, contributing over 94.5% and 64.4%, respectively. The confirmatory test showed that Taguchi DOE could reliably be used to predict the effects of powder mass and compaction pressure on K IC and RD of the aluminum powder compact.