Research on production of microgroove arrays on TiAl intermetallic alloy by micro milling

TiAl intermetallic alloy is a superior lightweight material with excellent performance, and its micro features or components have promising applications in manufacturing fields. In this work, an investigation of micro milling of microgroove arrays on TiAl alloy was studied. The effects of cutting parameters including the feed per tooth (f_z) and depth of cut (a_p) on the milling force, surface morphology, surface roughness and burr size of the micro-slots were investigated. The wear types and mechanisms of the micro end mills were also studied. The results showed that the optimal cutting parameters were f_z = 3.5 μm/z and a_p = 4 μm, which provided the best surface roughness S_a of 152 nm, top-burr heights on up- and down-milling sides of 19 and 19.5 μm respectively. Using the optimized cutting parameters, microgrooves with a width of 500 μm, aspect ratio of 5 and array period of 10 were fabricated successfully. Surface topography, dimensional accuracy and perpendicularity of the microgroove arrays were characterized. Results demonstrated that an increase in the microgroove number, microgroove edge chipping as well as burrs of the entrance and exit increased gradually. The dimensional error between the obtained width and the designed width of the microgroove was less than 2%, and the slope of the sidewalls reached more than 89°. The wear mechanisms of the micro end mills were abrasive wear and adhesive wear, and wear types were coating delamination, cutting edge chipping, and tool nose breakage.