Study of the effect of heat treatment on fatigue crack growth behaviour of 316L stainless steel produced by selective laser melting

Abstract

This study is focused on stainless steel type 316L produced by selective laser melting (SLM). This steel is very resistant to corrosion in acidic environments and has extremely good strength properties at elevated temperatures. It is also characterized by a very good weldability. These properties allow for various applications of 316L in different fields. The widespread application of 316L opens up various possibilities for production of parts using SLM. Therefore, it is important to characterize the fatigue crack growth behaviour. In the present paper, the crack growth behaviour of SLM 316L stainless steel has been investigated in its as‐built condition and in different heat treatment conditions. The effect of build orientation on the crack growth path is also studied by performing fatigue crack growth tests on compact tension specimens built at 0° and 45° orientations relative to the build direction. A heat treatment above the recrystallization temperature followed by quenching is shown to create compressive residual stresses that improve the resistance against crack propagation considerably. The 45° build orientation shows crack propagation at an angle to the initial notch plane, which reveals that anisotropy still persists after heat treatment.

Aeronautical and Aerospace Material and Structural Damages to Failures: Theoretical Concepts

“…With regard to material science and its theory and applications traced with the references of [6][7][8][9][10][11][12], the presented herewith entropy approach also gives some plausible results.…”

“…The sense of the uncertain multiplier x becomes obvious with the use of the normalizing condition of the initial functional in (1). That is, with the use of the presupposed relations of (7), (8), (9), and (10) 12 , 13…”

“…Therefore, from the expressions for the corresponding hybrid optional effectiveness functions in (9) and (10) (1), it is possible to find an optimal distribution of the hybrid optional effectiveness functions starting with the functional (1) extremum existence conditions of (2) and (3).…”

“…Possible fields of the proposed approach application are morphing aeronautical structures [6,7], different investigations on the influence of process parameters [8], and effects of heat treatment on fatigue [9] crack growth. Also, the models can be used at modeling the volume-based strain energy density approach [10], as well as fatigue strength subject to cyclic loading [11] and modifications of the activation energy, like for the material purposes discussed in the Sixth World Congress report in [12].…”

Investigation of the anisotropic cyclic damage behavior of selective laser melted AISI 316L stainless steel

“…This is supported by a comparable crack growth rate for both 0°and 45°orientations. 29 Another aspect to be considered is the higher amount of pores in the 45°specimens compared with the high-volume pores in the 0°s pecimens being also very detrimental for fatigue life and causing similar effects by creating multiple locations for crack initiation (Figure 7), and later combine and, thus, reducing the fatigue life in a similar way as it can be the case for a single high-volume pore.…”