Abstract

The purpose of this work is to determine and analyze residual stress normal components and anisotropy degrees introduced by high-speed milling in specimens of AA 6082-T6 and AA 7075-T6 aluminum alloys. At each machined sample, the climb and conventional cutting zones were evaluated and compared. This paper includes a comprehensive study of thermal and mechanical effects associated with the residual stress introduction. For normal components determination, an optimized micro-indent method was used. Each measurement sequence from this approach was performed using a high accuracy measuring machine and classified according to thermal deviations measured. The residual displacements were determined with an absolute error down to ±300 nm. The normal components analysis allowed to infer the strong influence of the rolling process previous to high-speed milling and besides, the stress levels associated with thermal effects (higher in AA 7075-T6). Finally, the lower residual stress anisotropy degrees in both materials observed in the conventional cutting zone would indicate more homogenous local plastic stretching in this region for all planar directions.

Keywords:

Aluminum alloys, anisotropy, high-speed milling, micro-indent method, residual stresses,

References

1. Brinksmeier, E., J.T. Cammett, W. Konig, P. Leskovar, J. Peters and H.K. Tonshoff, 1982. Residual stresses-measurement and causes in machining processes. CIRP Ann., 31(2): 491-510.
   CrossRef    
2. Díaz, F.V., G.H. Kaufmann and O. Möller, 2001. Residual stress determination using blind-hole drilling and digital speckle pattern interferometry with automated data processing. Exp. Mech., 41(4): 319-323.
   CrossRef    Direct Link
3. Díaz, F.V., R.E. Bolmaro, A.P.M. Guidobono and E.F. Girini, 2010. Determination of residual stresses in high speed milled aluminium alloys using a method of indent pairs. Exp. Mech., 50(2): 205-215.
   CrossRef    
4. Díaz, F.V. and C.A. Mammana, 2012. Study of residual stresses in conventional and high-speed milling. In: Filipovic, L.A. (Ed.), Milling: Operations, Applications and Industrial Effects. Nova Science Publishers, Inc., New York, pp: 127-155.
   
5. Díaz, F., C. Mammana and A. Guidobono, 2012. Evaluation of residual stresses induced by high speed milling using an indentation method. Modern Mech. Eng., 2(4): 143-150.
   CrossRef    
6. Díaz, F.V., C.A. Mammana and A.P.M. Guidobono, 2015. Evaluation of residual stresses in low, medium and high speed milling. Res. J. Appl. Sci. Eng. Technol., 11(3): 252-258.
   CrossRef    Direct Link
7. Gere, J.M., 2004. Mechanics of Materials. 5th Edn., Brooks/Cole, Pacific Grove, CA.
   
8. Gupta, B.P., 1973. Hole-drilling technique: Modifications in the analysis of residual stresses. Exp. Mech., 13(1): 45-48.
   CrossRef    
9. Jacobus, K., S.G. Kapoor and R.E. DeVor, 2001. Experimentation on the residual stresses generated by endmilling. J. Manuf. Sci. Eng., 123(4): 748-753.
   CrossRef    
10. Lu, J., 1996. Handbook of Measurement of Residual Stresses. Fairmont Press, Lilburn, Geéorgie: Upper Saddle River, N.J.
    
11. Noyan, I.C. and J.B. Cohen, 1987. Residual Stress Measurement by Diffraction and Interpretation. Springer Verlag, Berlin.
    
12. Prevéy, P.S., 1987. X-ray Diffraction Residual Stress Techniques. Metals Handbook, American Society for Metals, Metals Park, OH, pp: 380-392.
    
13. Rao, B. and Y.C. Shin, 2001. Analysis on high-speed face-milling of 7075-T6 aluminum using carbide and diamond cutters. Int. J. Mach. Tool. Manu., 41(12): 1763-1781.
    CrossRef    
14. Rendler, N.J. and I. Vigness, 1966. Hole-drilling strain-gage method of measuring residual stresses. Exp. Mech., 6(12): 577-586.
    CrossRef    
15. Rowlands, R.E., 1987. Residual Stresses. In: Kobayashi, A. (Ed.), Handbook on Experimental Mechanics. Prentice-Hall, New Jersey, pp: 768-813.
    
16. Schulz, H., 2003. High-speed Machining. In: Dashchenko A.I. (Ed.), Manufacturing Technologies for Machines of the Future. Springer, Berlin, pp: 197-214.
    CrossRef    
17. Suresh, S. and A.E. Giannakopoulos, 1998. A new method for estimating residual stresses by instrumented sharp indentation. Acta Mater., 46(16): 5755-5767.
    CrossRef    
18. Swadener, J.G., B. Taljat and G.M. Pharr, 2001. Measurement of residual stress by load and depth sensing indentation with spherical indenters. J. Mater. Res., 16(7): 2091-2102.
    CrossRef    
19. Timoshenko, S.P. and J.N. Goodier, 1970. Theory of Elasticity. McGraw-Hill, New York.
    CrossRef    
20. Trent, E.M., 1991. Metal Cutting. 3rd Edn., Butterworth/ Heinemann, London.
    CrossRef    
21. Vottero, S., F.V. Díaz, C.A. Mammana and A.P.M. Guidobono, 2017. Analysis of residual stresses in high speed milled aluminum alloys. Res. J. Appl. Sci. Eng. Technol., 14(3): 119-123.
    CrossRef    
22. Wyatt, J.E. and J. Berry, 2006. A new technique for the determination of superficial residual stresses associated with machining and other manufacturing processes. J. Mater. Proc. Tech., 171(1): 132-140.
    CrossRef    
23. Wyatt, J.E. and J. Berry, 2009. Mapping of superficial residual stresses in machined components. J. Ind. Technol., 25(1): 1-8.
    Direct Link
24. Zhao, M., X. Chen, J. Yan and A.M. Karlsson, 2006. Determination of uniaxial residual stress and mechanical properties by instrumented indentation. Acta Mater., 54(10): 2823-2832.
    CrossRef    

Competing interests

The authors have no competing interests.

Open Access Policy

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Copyright

The authors have no competing interests.