Application of Taguchi design method for optimization of spark plasma sintering process parameters for Ti-6Al-4V/ <i>h</i> -BN binary composite

Abstract

Taguchi design method of optimization facilitates standard experimental research, lowers cost, conserves energy and time, minimizes waste and ensures optimal outcomes. In this work, Taguchi L9 34 orthogonal array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA) statistical procedures were applied to evaluate the influence of sintering parameters/levels on the relative densification and microhardness of Ti-6Al-4V/h -BN binary composite sintered. The S/N ratios revealed that heating rate with delta value of 0.24, followed by temperature with delta value of 0.22 impart the most significant influence on the optimal quality characteristics. One-way ANOVA statistical analyses showed that heating rate imparts the greatest influence on relative densification with 36.25% contribution, followed by temperature with 31.33% contribution, whereas temperature gave the highest contribution of 34.12%, followed by heating rate with 23.31% contribution for microhardness. The optimal parameters/levels for most desirable characteristics were obtained at 1000 °C, 30 MPa, 100 °C min−1 and 10 min. The spark plasma sintered Ti6Al4V-3h-BN composite with the optimized parameters/levels attained nearly full theoretical densification of 99.54% and the sintered composite gave a microhardness value of 716.43 HV which is more than 200% that of the monolithic alloy. The confirmation test revealed that the improvement in relative densification and microhardness at the optimum parameters/levels are 1.55% and 19.2% of the arithmetic means of the initial relative densification and microhardness measurements respectively.