Mechanochemical effect on the microstructure and mechanical properties in ultraprecision machining of AA6061 alloy

Jiayi Zhang，Yan Jin Lee，Hao Wang

Department of Mechanical Engineering, Faculty of Engineering, National University of Singapore

摘 要：The mechanochemical effect on the microcutting of AA6061 alloy is studied through characterization on the microgroove surface. There is a reduction in cutting and thrust forces with the application of ink during microcutting. Moreover, the microhardness of the ink-affected microgroove is lower than that of the ink-free microgroove. Numerous substructured grains exist in the ink-affected microgroove zone whilst deformed grains dominate in the ink-free microgroove zone produced by microcutting. Furthermore, the mechanochemical effect can facilitate the nucleation of precipitates in the microgroove zone and induce the formation of subgrains with multiple orientations. According to the analysis and calculation, the main texture components of the ink-affected sample are Goss {110}<001> and R {124}<211>, and that of the ink-free sample are Brass {110}<112>, Copper {112}<111> and S {123}<634>. Besides, a clear difference of slip systems is found between the ink-free and ink-affected microgrooves, and the results show that R texture is easier to form on the ink-affected microgroove.

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