PSI - Issue 24

Maria Rita Ridolfi et al. / Procedia Structural Integrity 24 (2019) 370 – 380 Maria Rita Ridolfi et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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In the second stage, height h and   are varied with varying laser parameters until fitting measured values of depth and width. In particular, absorptivity increases with increasing the input laser specific energy until reaching a plateau at a value close to unity. Laser efficiency   has been kept constant and equal to 0.85. Table 1 resumes the main thermo-physical parameters for the three alloys.

Table 1 . Thermo-physical properties of the three alloys used for the model calibration.

Metal alloy

Ti6Al4V

INC625

Al7050

Density (kg m -3 )

4000 1986 1970

8440 1607 1513

2810

Liquidus temperature: T liq (K) Solidus temperature: T sol (K)

906 787

Specific heat (J kg -1 K -1 )

ambient temperature

550 830 980

440 650 670

860

T sol T liq

1050 1120

Thermal conductivity (W m -1 K -1 )

ambient temperature

5

11 30 30 90

117 156

T sol T liq

32 32 96

87

T>T liq

148

Latent heat of fusion (J m 3 ) Boiling temperature (K) Reflectivity at 1.06  m

1.4 10 9

1.99 10 9

1.05 10 9

3560 0.52

3003 0.71

2793 0.65

5. Results

The comparison between measured and calculated cross sectional data are shown in Fig. 3, in terms of width and depth data concerning the analysis performed on Ti6Al4V (Dilip et al. (2017)) and Al7050 (Qi et al. (2017)), respectively in Fig 3 (a) and (c), and of cross sectional area for Inconel 625 (Montgomery et al. (2015)) in Fig. 3 (b).

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