• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2021, Vol. 57 ›› Issue (9): 254-263.doi: 10.3901/JME.2021.09.254

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Investigation on Laser-induced Controllable Oxidation Assisted Micro Milling of Titanium Aluminum Intermetallic Alloy

ZHAO Guolong, XIA Hongjun, LI Liang, XIN Lianjia, HE Ning   

  1. College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016
  • Received:2020-06-01 Revised:2020-12-15 Online:2021-05-05 Published:2021-06-15

Abstract: The poor rigidity of micro tools and the high cutting force are the main reasons for the low manufacturing efficiency, poor surface quality and low processing controllability in micro milling of TiAl intermetallic alloy. In this work, an innovative hybrid machining process of laser-induced controllable oxidation assisted micro milling (LOMM) is proposed. At average laser power of 4.5 W, scanning speed of 1 mm/s and oxygen-rich atmosphere, loose and porous oxide layer is produced, which is easy to be removed with extremely low milling force and no tool wear. The oxidation mechanism of the material under laser irradiation is revealed. In addition, the effects of depth of cut and feed per tooth on milling force, surface quality and tool wear are studied. For a comparison, conventional micro milling (COMM) is carried out under identical milling parameters. Results reveal that the oxidation reaction proceeds smoothly at a low average laser power and scanning speed. Loose and porous oxide is produced, which mainly consist of anatase TiO2 and rutile TiO2. In addition, the sub-layer is flat with micro-crack as well as small amount of remained oxides. The milling force and tool wear in LOMM are lower than those in COMM. At feed per tooth of 3.5 μm/z and depth of cut of 4 μm, surface roughness achieved in LOMM is 128 nm. The main wear types of the micro end mill in LOMM are coating spalling and adhesion. Compared with COMM, the tool life in LOMM is prolonged significantly.

Key words: TiAl intermetallic alloy, laser-induced oxidation, micro milling, hybrid machining, tool wear

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