Surface texturing by dimple formation in TiAlSiZr alloy using μ-EDM

Abstract

Surface texturing by micro dimple formation is adopted in many applications to improve the tribological properties of materials. This work investigates dimple formation in titanium (TiAlSiZr) alloy using micro-electrical discharge machining (μ-EDM). Circular dimples were formed by varying the EDM parameters, that is, the capacitance (1000 and 10,000 pF), pulse-on time (100, 150, and 200 μs), and voltage (180, 200, and 220 V). The output responses such as burr height, burr width, and aspect ratio of the dimples were analyzed. The experimental results show that an ideal output response is obtained by simultaneously using a lower capacitance and a higher pulse-on time and voltage. The reason is the influence of these parameters on the spark energy and material removal rate, which determine the micro dimple geometry. Regression analysis was performed to predict the values, and the developed model showed goodness of fit. Further, desirability analysis was used to predict the optimal conditions (a capacitance of 1000 pF, pulse-on time of 178 μs, and voltage of 220 V), and the results were validated using confirmation experiments. The results were found to be in good agreement at the 95% confidence and prediction levels. Micrographs of the dimples and the three-dimensional micro dimple geometry were also analyzed.