Microstructural evolution of Ti6Al4V in ultrasonically assisted cutting: Numerical modelling and experimental analysis.
This paper aims to elucidate the effect of ultrasonically assisted cutting (UAC) on microstructure in a machined surface and a chip of Ti6Al4V alloy. To investigate microstructural evolution, a FE-based cutting model with an enhanced material formulation and temperature dependent material properties was developed. A Johnson-Mehl-Avrami-Kolmogorov (JMAK) model for the Ti6Al4V alloy was employed to simulate dynamic recrystallization and predict a resultant grain size. Due to a specific thermomechanical load in UAC, the distributions of strains, strain rates and temperatures in a workpiece in the machining process were investigated. In this study, five points under the machined surface and ten points under the unmachined one were tracked to compare the evolution of a grain size and its average magnitude in the alloy subjected to conventional cutting (CC) and UAC. Besides of numerical modelling and experimental studies for the resultant grain size were compared and additional validation using microhardness measurements were conducted. The results showed that the average grain size of the machined surface and the chip in case of UAC was larger and more uniform than that in case of CC. The study also presents discussions about the effect of a vibration amplitude, a feed rate and a cutting speed on the average grain size in machining of Ti6Al4V. The comparison between CC and UAC indicates that the change in average grain size in UAC was smaller than that in CC, thus demonstrating a lower level of damage in UAC.
The State Key Lab of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
Wei
W
Bai
The State Key Lab of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China. Electronic address: ronglei@hust.edu.cn.
Ronglei
R
Sun
TBZ-PARIV GmbH, Chemnitz 09126, Germany.
Jürgen
J
Leopold
Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Leicestershire LE11 3TU, UK.
Vadim V
VV
Silberschmidt
Dynamic recrystallization; Low-damage process; Microstructure; Numerical modelling; Ultrasonically assisted cutting