Numerical Simulation of Cutting-Induced Grain Refinement in Machining Process under Dry and MQL Conditions of Titanium Ti-5553 Alloy

The Ti-5553 alloy, known as the new generation high temperature near beta alloy, is used in the aerospace industry to replace the commonly used Ti-6Al-4V due to its high tensile strength and fatigue life. In this study, a wide range of cutting speed effects on grain refinement of finite element simulation of orthogonal machining of Ti-5553 alloy is investigated. In particular, the purpose of this research is to investigate the effects of the dry and minimum quantity lubrication (MQL) on the predicted cutting forces, cutting temperature and grain size. A user subroutine equation of Zener-Hollomon model is developed to simulate the modifications of grain size in the machined surface generation under different cutting conditions and speeds. The simulation results of the microstructure evolution in machined surfaces are compared with experimental results obtained by scanning electron microscopy (SEM). The compared results show that the evolution of the grain size of Ti-5553 under dry and MQL conditions can be accurately predicted by the Zener-Hollomon model. For both cutting conditions, it is observed that the frequency of smaller grain sizes increased with increasing cutting speed.