Power lasers

Superficial treatments using high-energy-density beams

Figure 1 - Schematic diagram of laser essentials

Figure 2 - First vibrational energy levels of CO2 and N2 and transition lifetimes (after A. Orsfag and G. Hepner).

Figure 3 - Energy transition levels of Nd in YAG (after A.E. Siegman)

Figure 4 - Potential energy diagram of an excimer molecule (after A. Orsfag and G. Hepner)

Figure 5 - Diagram of laser beam-matter thermal interaction (after J.P. and C. Girardeau-Montaut)

Figure 6 - Absorption coefficient as a function of laser beam wavelength (after R. Dekumbis)

Figure 7 - Absorption coefficient as a function of the angle of incidence of the laser beam for a polished metal surface (after R. Dekumbis)

Figure 8 - Absorption coefficient as a function of laser beam scanning speed for medium-carbon steel (after J.H.P.C. Megaw and A.S. Kaye)

Figure 9 - Absorption coefficient as a function of temperature for stainless steel (after J.P. and C. Girardeau-Montaut)

Figure 10 - Photoelectronic beam-metal surface interaction (after H.W. Bergmann and E. Schubert)

Figure 11 - Beam modulated for rectangular energy distribution (after M. Inagaki, R. Jimbou and S. Shiono)

Figure 12 - Beam modulated for rectangular energy distribution in two directions (after D.N.H. Trafford, T. Bell, J.H.P.C. Megaw and A.S. Bransden)

Figure 13 - Examples of cylindrical surface treatments (after O.A. Sandven, A.B. Vannes and Y. Guan)

Figure 14 - Experimental devices for laser reloading (from Établissement Technique Central de l&#039;Armement)

Figure 15 - Different gassing techniques (after W.M. Steen)

Figure 16 - Energy absorption profile for laser and electron beams

Figure 17 - Principles of electron beam surface treatment (after P.R. Strutt)

Figure 18 - Temperature effect – phase change – stress during FHDE surface treatment

Figure 19 - Industrial applications of laser beams (after R. Streiff)

Figure 20 - Microhardness evolution of light and dark martensites (after A. Mulot and J.P. Badeau)

Figure 21 - Study of residual stresses after laser treatment (after P.A. Molian)

Figure 22 - Wöhler curves for GS cast iron (after P.A. Molian)

Figure 23 - Wear rate and coefficient of friction as a function of time (after L.N. Obishchenko et al )

Figure 24 - Forces in the molten bath by FHDE

Figure 25 - Shape of molten bath during surface melting by FHDE for high scanning speeds vb (after B.L. Mordike)

Figure 26 - Relationship between solidification morphologies, solidification rate vs , temperature gradient G and cooling rate vr

Figure 27 - Microhardness of the surface zone of laser-remelted cast iron with different protective gases (after I. Hawkes, L. Lundberg, A.M. Walker, W.M. Steen and D.R.F. West)

Figure 28 - Steps involved in laser surface alloying (after C.W. Draper and J.M. Poate)

Figure 29 - Schematic of laser shock hardening experiment (after G. Barreau, P. Ballard and J. Fournier)