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Serrated chip characteristics and formation mechanism in high-speed machining of selective laser melted Ti6Al4V alloys

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Abstract

Serrated chips, consisting of extremely uneven plastic deformation, are a prominent feature of high-speed machining of difficult-to-machine materials. This paper focuses on the evolution of chip form, chip morphology features (chip free surface, tool-chip contact surface, and chip edge), and chip segment parameters in subsequent high-speed (vc=50 and 150 m min−1) machining of selective laser melted (SLMed) Ti6Al4V alloys, which are significantly different from conventional Ti6Al4V alloy in microstructure, mechanical properties and machinability. The effect of laser beam scanning schemes (0°, 67.5°, and 90°), machined surfaces (top and front), and cutting speeds on serrated chip characteristics of SLMed Ti6Al4Valloys was investigated. Based on the Johnson-Cook constitutive model of SLMed Ti6Al4V alloys, an orthogonal cutting model was developed to better understand the effect of physical-mechanical properties on the shear localization, which dominates the formation mechanism of serrated chips in post-machining of SLMed Ti6Al4V alloy. The results showed that the critical cutting speed (CCS) for chip serration of SLMed Ti6Al4V alloy is lower than that for serrated chips of conventional Ti6Al4V alloy, and the serrated profile of SLMed Ti6Al4V chips was more regular and pronounced. Besides, due to anisotropic microstructure and mechanical properties of SLMed Ti6Al4V alloys, the serration degree of chips produced on the top surfaces of SLMed Ti6Al4V alloys is more prominent than that of chips generated on the front surfaces. In addition, because of the poor deformation coordination and high plastic flow stresses of needle-like martensite α′, the plastic flow and grain distortion in the adiabatic shear band (ASB) of SLMed Ti6Al4V chips are significantly smaller than those in the ASB of conventional Ti6Al4V with equiaxed grains.

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References

  1. Kok Y, Tan X P, Wang P, et al. Anisotropy and heterogeneity of microstructure and mechanical properties in metal additive manufacturing: A critical review. Mater Des, 2018, 139: 565–586

    Article  Google Scholar 

  2. Maleki E, Bagherifard S, Bandini M, et al. Surface post-treatments for metal additive manufacturing: Progress, challenges, and opportunities. Add Manuf, 2021, 37: 101619

    Google Scholar 

  3. Bai Y, Zhao C, Yang J, et al. Microstructure and machinability of selective laser melted high-strength maraging steel with heat treatment. J Mater Process Tech, 2021, 288: 116906

    Article  Google Scholar 

  4. Yu H, Yang J, Yin J, et al. Comparison on mechanical anisotropies of selective laser melted Ti-6Al-4V alloy and 304 stainless steel. Mater Sci Eng-A, 2017, 695: 92–100

    Article  Google Scholar 

  5. Zheng Z, Jin X, Bai Y, et al. Microstructure and anisotropic mechanical properties of selective laser melted Ti6Al4V alloy under different scanning strategies. Mater Sci Eng-A, 2022, 831: 142236

    Article  Google Scholar 

  6. Fernandez-Zelaia P, Nguyen V, Zhang H, et al. The effects of material anisotropy on secondary processing of additively manufactured CoCrMo. Add Manuf, 2019, 29: 100764

    Google Scholar 

  7. Ni C B, Zhu L D, Zheng Z P, et al. Effect of material anisotropy on ultra-precision machining of Ti-6Al-4V alloy fabricated by selective laser melting. J Alloys Compd, 2020, 848: 156457

    Article  Google Scholar 

  8. Ni C, Zhu L, Zheng Z, et al. Effects of machining surface and laser beam scanning strategy on machinability of selective laser melted Ti6Al4V alloy in milling. Mater Des, 2020, 194: 108880

    Article  Google Scholar 

  9. Grove T, Denkena B, Maiβ O, et al. Cutting mechanism and surface integrity in milling of Ti-5553 processed by selective laser melting. J Mech Sci Technol, 2018, 32: 4883–4892

    Article  Google Scholar 

  10. Fei J, Liu G, Patel K, et al. Cutting force investigation in face milling of additively fabricated nickel alloy 625 via powder bed fusion. Int J Mech Manuf Systems, 2019, 12: 196–210

    Google Scholar 

  11. Shunmugavel M, Goldberg M, Polishetty A, et al. Chip formation characteristics of selective laser melted Ti-6Al-4V. Aust J Mech Eng, 2019, 17: 109–126

    Article  Google Scholar 

  12. Fu X L, Lin W X, Pan Y Z, et al. Morphology evolution and micromechanism of chip formation during high-speed machining. Int J Adv Manuf Technol, 2018, 98: 165–175

    Article  Google Scholar 

  13. Childs T H C, Arrazola P J, Aristimuno P, et al. Ti6Al4V metal cutting chip formation experiments and modelling over a wide range of cutting speeds. J Mater Process Tech, 2018, 255: 898–913

    Article  Google Scholar 

  14. Zang J, Zhao J, Li A, et al. Serrated chip formation mechanism analysis for machining of titanium alloy Ti-6Al-4V based on thermal property. Int J Adv Manuf Technol, 2018, 98: 119–127

    Article  Google Scholar 

  15. Jomaa W, Mechri O, Lévesque J, et al. Finite element simulation and analysis of serrated chip formation during high-speed machining of AA7075-T651 alloy. J Manuf Process, 2017, 26: 446–458

    Article  Google Scholar 

  16. Wan Z P, Zhu Y E, Liu H W, et al. Microstructure evolution of adiabatic shear bands and mechanisms of saw-tooth chip formation in machining Ti6Al4V. Mater Sci Eng-A, 2012, 531: 155–163

    Article  Google Scholar 

  17. Sun J, Guo Y B. A new multi-view approach to characterize 3D chip morphology and properties in end milling titanium Ti-6Al-4V. Int J Mach Tools Manuf, 2008, 48: 1486–1494

    Article  Google Scholar 

  18. Calamaz M, Coupard D, Nouari M, et al. Numerical analysis of chip formation and shear localisation processes in machining the Ti-6Al-4V titanium alloy. Int J Adv Manuf Technol, 2011, 52: 887–895

    Article  Google Scholar 

  19. Sutter G, List G. Very high speed cutting of Ti-6Al-4V titanium alloy—Change in morphology and mechanism of chip formation. Int J Mach Tools Manuf, 2013, 66: 37–43

    Article  Google Scholar 

  20. Su G, Liu Z. An experimental study on influences of material brittleness on chip morphology. Int J Adv Manuf Technol, 2010, 51: 87–92

    Article  Google Scholar 

  21. Li A, Zang J, Zhao J. Effect of cutting parameters and tool rake angle on the chip formation and adiabatic shear characteristics in machining Ti-6Al-4V titanium alloy. Int J Adv Manuf Technol, 2020, 107: 3077–3091

    Article  Google Scholar 

  22. Su G, Liu Z, Li L, et al. Influences of chip serration on micro-topography of machined surface in high-speed cutting. Int J Mach Tools Manuf, 2015, 89: 202–207

    Article  Google Scholar 

  23. Zhu Z, Sun J, Li J, et al. Investigation on the influence of tool wear upon chip morphology in end milling titanium alloy Ti6Al4V. Int J Adv Manuf Technol, 2016, 83: 1477–1485

    Article  Google Scholar 

  24. Molinari A, Musquar C, Sutter G. Adiabatic shear banding in high speed machining of Ti-6Al-4V: Experiments and modeling. Int J Plast, 2002, 18: 443–459

    Article  MATH  Google Scholar 

  25. Zhao X, Li S, Zhang M, et al. Comparison of the microstructures and mechanical properties of Ti-6Al-4V fabricated by selective laser melting and electron beam melting. Mater Des, 2016, 95: 21–31

    Article  Google Scholar 

  26. Liu C, Wan M, Zhang W, et al. Chip formation mechanism of Inconel 718: A review of models and approaches. Chin J Mech Eng, 2021, 34: 34

    Article  Google Scholar 

  27. Ni C B, Zhu L D. Investigation on machining characteristics of TC4 alloy by simultaneous application of ultrasonic vibration assisted milling (UVAM) and economical-environmental MQL technology. J Mater Process Tech, 2020, 278: 116518

    Article  Google Scholar 

  28. Yang J, Yu H, Yin J, et al. Formation and control of martensite in Ti-6Al-4V alloy produced by selective laser melting. Mater Des, 2016, 108: 308–318

    Article  Google Scholar 

  29. Han J, Yang J, Yu H, et al. Microstructure and mechanical property of selective laser melted Ti6Al4V dependence on laser energy density. Rapid Prototyp J, 2017, 23: 217–226

    Article  Google Scholar 

  30. Aydın M, Köklü U. Analysis of flat-end milling forces considering chip formation process in high-speed cutting of Ti6Al4V titanium alloy. Simul Model Pract Theor, 2020, 100: 102039

    Article  Google Scholar 

  31. Johnson G R, Cook W H. Fracture characteristics of three metals subjected to various strains, strain rates, temperatures and pressures. Eng Fract Mech, 1985, 21: 31–48

    Article  Google Scholar 

  32. Harzallah M, Pottier T, Senatore J, et al. Numerical and experimental investigations of Ti-6Al-4V chip generation and thermo-mechanical couplings in orthogonal cutting. Int J Mech Sci, 2017, 134: 189–202

    Article  Google Scholar 

  33. Zorev N. Interrelationship between shear processes occurring along tool face and on shear plane in metal cutting. In: ASME Proc Int Res Prod Eng. New York, 1963. 42–49

  34. Zhang Y, Outeiro J C, Mabrouki T. On the selection of Johnson-Cook constitutive model parameters for Ti-6Al-4V using three types of numerical models of orthogonal cutting. Proc CIRP, 2015, 31: 112–117

    Article  Google Scholar 

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Correspondence to ChenBing Ni.

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This work was supported by the National Natural Science Foundation of China (Grant Nos. 51975112 and 51575289). The authors are very grateful to Prof. LU WenFeng and Prof. WANG Hao from the National University of Singapore (NUS) for their guidance and assistance in the experiment.

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Liu, D., Wang, Y., Ni, C. et al. Serrated chip characteristics and formation mechanism in high-speed machining of selective laser melted Ti6Al4V alloys. Sci. China Technol. Sci. 66, 1435–1450 (2023). https://doi.org/10.1007/s11431-022-2304-1

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  • DOI: https://doi.org/10.1007/s11431-022-2304-1

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