Finite element simulation for Ti-6Al-4V alloy deformation near the exit of orthogonal cutting

Ti-6Al-4V alloy is known as a typical difficult-to-machine hard material due to its inherent properties such as low thermal conductivity, low elastic modulus, and high reactivity with cutting tool materials. This paper proposes a two-dimensional coupled thermo-mechanical model of plane strain orthogonal cutting for Ti-6Al-4V alloy deformation near the exit edge. Johnson–Cook material constitutive model and Cockroft–Latham damage criterion are utilized in the model for better understanding the plastic behavior and chips formation during the cutting process. The machining parameters such as cutting speed, tool edge radius, rake angle, and cutting depth are taken into account in the simulation. The results show that an edge defect generates at the exit edge after machining. The edge defect consists of two fracture surfaces, namely, the first fracture surface of opening-mode crack and the second fracture surface of sliding-mode crack. Besides, the edge defect sizes are greatly sensitive to machining parameters. This study provides a better understanding of burr/breakout formation mechanism near the exit surface and optimization of machining parameters in cutting Ti-6Al-4V alloy.

[1]  Sung-Lim Ko,et al.  Burr formation and fracture in oblique cutting , 1996 .

[2]  Taylan Altan,et al.  A finite element analysis of orthogonal machining using different tool edge geometries , 2004 .

[3]  Bo Lindström,et al.  The effect of restricted contact length on tool performance , 1995 .

[4]  Ken-ichiro Mori,et al.  The application of some criteria for ductile fracture to the prediction of the forming limit of sheet metals , 1999 .

[5]  Yucan Fu,et al.  Workpiece surface quality when ultra-precision turning of SiCp/Al composites , 2008 .

[6]  D. Umbrello.  Finite element simulation of conventional and high speed machining of Ti6Al4V alloy , 2008 .

[7]  A. A. Nazarov,et al.  Relaxation of a disclinated tricrystalline nanowire , 2008 .

[8]  D. Agard,et al.  Microtubule nucleation by γ-tubulin complexes , 2011, Nature Reviews Molecular Cell Biology.

[9]  Sangkee Min,et al.  Burrs—Analysis, control and removal , 2009 .

[10]  Victor Songmene,et al.  Modeling of burr thickness in milling of ductile materials , 2013 .

[11]  C. H. Che-Haron,et al.  Tool life and surface integrity in turning titanium alloy , 2001 .

[12]  J. Fundenberger,et al.  Sub-surface and surface analysis of high speed machined Ti–6Al–4V alloy , 2010 .

[13]  Sung-Lim Ko,et al.  A New Burr Formation Model for Orthogonal Cutting of Ductile Materials , 2006 .

[14]  M. Estrems,et al.  Finite element analysis of optimum clearance in the blanking process , 1998 .

[15]  Z. Jian,et al.  A Comparative Research of Damaged Layers Formed in Surface Grinding and Wire-Electrodischarge Machining , 2011 .

[16]  Yang Wang,et al.  A constitutive description of tensile behavior for brass over a wide range of strain rates , 2004 .

[17]  P. T. Blotter,et al.  The Formation and Properties of Machining Burrs , 1976 .

[18]  Y. Karpat.  Temperature dependent flow softening of titanium alloy Ti6Al4V: An investigation using finite element simulation of machining , 2011 .

[19]  Wenfeng Ding,et al.  The influence of speed on material removal mechanism in high speed grinding with single grit , 2015 .

[20]  Z. M. Wang,et al.  Titanium alloys and their machinability—a review , 1997 .

[21]  David Dornfeld,et al.  A Study of Burr Formation Processes Using the Finite Element Method: Part II—The Influences of Exit Angle, Rake Angle, and Backup Material on Burr Formation Processes , 2000 .

[22]  E. El-Magd,et al.  Description of flow curves over wide ranges of strain rate and temperature , 2006 .

[23]  David Dornfeld,et al.  Analysis of fracture in burr formation at the exit stage of metal cutting , 1996 .

[24]  F. Girot,et al.  A new material model for 2D numerical simulation of serrated chip formation when machining titanium alloy Ti–6Al–4V , 2008 .

[25]  Fabrizio Micari,et al.  A critical analysis on the friction modelling in orthogonal machining , 2007 .

[26]  David Dornfeld,et al.  A study on Burr formation mechanism , 1991 .

[27]  E. Ezugwu,et al.  An overview of the machinability of aeroengine alloys , 2003 .

[28]  Yinghui Ren,et al.  Analysis and FEM Simulation of Temperature Field in Wet Surface Grinding , 2010 .

[29]  Ning Hou,et al.  An experimental study on formation mechanisms of edge defects in orthogonal cutting of SiCp/Al composites , 2014 .

[30]  Y. Wang,et al.  Finite element and experimental studies of the formation mechanism of edge defects during machining of SiCp/Al composites , 2014 .

[31]  Kun Zhou,et al.  Modeling cracks and inclusions near surfaces under contact loading , 2014 .

[32]  David Dornfeld,et al.  Burr/Breakout Model Development and Experimental Verification , 1996 .

[33]  Yi Wan,et al.  Finite element simulation of machining of Ti-6Al-4V alloy with thermodynamical constitutive equation , 2010 .

[34]  Christopher J. Evans,et al.  White Layers and Thermal Modeling of Hard Turned Surfaces , 1997, Manufacturing Science and Engineering: Volume 2.

[35]  J. Zhang,et al.  An experimental investigation of affected layers formed in grinding of AISI 52100 steel , 2011 .

[36]  Victor Songmene,et al.  Analytical modelling of slot milling exit burr size , 2014 .

[37]  Honghua Su,et al.  Development and performance of monolayer brazed CBN grinding tools , 2007 .

[38]  Ahmed Z. Al-Garni,et al.  Friction welding of StAl and AlCu materials , 1995 .

[39]  Chi Feng Lin,et al.  Plastic deformation and fracture behaviour of Ti–6Al–4V alloy loaded with high strain rate under various temperatures , 1998 .

[40]  Andrey Toropov,et al.  A model of burr formation in the feed direction in turning , 2006 .

[41]  Jiu-hua Xu,et al.  Finite element modeling of machining of hydrogenated Ti-6Al-4V alloy , 2012 .

[42]  David Dornfeld,et al.  A Study of Burr Formation Processes Using the Finite Element Method: Part I , 2000 .

[43]  A. A. Nazarov,et al.  Continuum and atomistic studies of a disclinated crack in a bicrystalline nanowire , 2006 .

[44]  Qihong Fang,et al.  Investigate on distribution and scatter of surface residual stress in ultra-high speed grinding , 2014 .

[45]  Yuqing Cao,et al.  Failure analysis of exit edges in ceramic machining using finite element analysis , 2001 .

[46]  Wei Xia,et al.  Finite element simulation for burr formation near the exit of orthogonal cutting , 2008 .

[47]  A. Jawaid,et al.  The effect of machining on surface integrity of titanium alloy Ti–6% Al–4% V , 2005 .