PSI - Issue 2_A

Andre Riemer et al. / Procedia Structural Integrity 2 (2016) 1229–1236 A. Riemer, H.A. Richard / Structural Integrity Procedia 00 (2016) 000–000

1234

6

a)

b)

Parameter set 1

Parameter set 2

1,0E-02

(30 µm)

(50 µm)

Parameter set 3

(100 µm)

1,0E-03

n

V

1,0E-04

0,8 1

1,0E-07 crack growth rate da/dN [mm/cycle ] 1,0E-06 1,0E-05

building direction

0,6

A n

 K th (RR AR) n

0,4

0,2

0

50µm (275W) 100µm (950W) 30µm (175W)

R p0,2 n

 K C (RR AR) n

1,0E-08

1

10

100

R m n

Stress intensity range  K [MPa·m 1/2 ]

Fig. 5. (a) Fatigue crack growth data depending on the laser power input (build-up rate); (b) Overall material performance depending on the parameter set (build-up rate). 3. Fatigue crack growth in laser melted implants In this study, the effect of treatment (and consequently of the residual stresses) on the component’s lifetime was analyzed. For that reason titanium alloy Ti-6-4 in the conditions As-built and 800° were taken into account. The required fatigue crack growth data, Fig. 6a, was characterized by the FORMAN/METTU-equation as follows:

q       p

1       1

K



I th



n

K



  

   

1

dN da





  

    

(1).

C

K





FM

I

1

R



K

C max



K

Fig. 6. (a) FORMAN/METTU-equation fitted to the data for As-built and 800°C conditions; (b) Fitting parameter sets for the FORMAN/METTU-equation.