Effects of dealloying surface modification on machinability improvement of NiTi alloy during micro-machining process

Abstract

In this work, a novel dealloying assisted machining (DAM) method is proposed to modify the machinability of a typical high toughness NiTi alloy. The DAM method can produce nanoporous layer on workpiece surface through dealloying process. Under different cutting depths, micro-milling experiments are performed on workpieces with and without dealloying surface modification. The results indicate that the embrittlement effect of nanoporous layer induce ductile to brittle transition during material removal process leading to the fragmented chip formation. Consequently, the cutting force and temperature decrease by over 14% and 12%, respectively. Meanwhile, the tool wear is alleviated and the machined surface quality is improved. The proposed method can also provide guidance for micro machining of other difficult-to-machine materials.