An investigation on the optimum machinability of NiTi based shape memory alloy

ABSTRACT

In the present work, the machinability of nickel–titanium (Nitinol) shape memory alloy has been discussed. Nitinol is known as a difficult-to-machine alloy due to its high hardness, which requires a large amount of cutting force, resulting in high rate of tool wearing. Therefore, researchers have made an effort to ameliorate the machinability of this material to achieve a finer surface quality. The previous studies found that the cutting speed will remarkably influence the surface properties of machined nickel–titanium alloy in turning process. Tool wear and cutting force are at minimum values in a particular range of cutting speeds so that it leads to diminishing machining barriers such as burr formation and chip-breaking. Lower cutting force and consequently lower temperature and stresses in the machining process improve the mechanical properties as well as reducing hardness, distortion, and residual stress. The machining process was optimized by applying a numerical approach through ANSYS/LS-DYNA R15 software. The obtained results demonstrated the optimum cutting speed in the machining process, which are in good agreement with experiments.

KEYWORDS:

• FEM
• machinability
• modeling
• NiTi
• Nitinol
• SMAs