Robert Eriksson's research while affiliated with Linköping University and other places

... AM is a technique that has garnered a lot of attention from industry because of its potential to create very complex components that provide increased opportunities to optimize components for performance and cost. 2 AM methods applied to metals, which are the most widely used engineering materials, are shown in Figure 1 in detail. This article specifically focuses on examining the fatigue performance of parts produced by metal AM processes. ...

... In Ref. [21], the influence of AM parameters, graded microstructures and optional heat treatments on the in-phase TMF lifetime were studied for Ni-base superalloy IN718. Lindström et al. [22] investigated and simulated the deformation behaviour of a Ni-base AM combustor alloy under in-phase and out-of-phase TMF loading with respect to maximum temperature and specimen orientation relative to the building direction. However, they did not report on the influence on lifetime. ...

... It can be observed that the porosity doesn't affect the compressive properties of the sample while the hardness effect can be seen on the compressive test. This is because the porosities may undergo closure during the compression test and may not have a significant influence [81][82][83]. The compressive strength of all three samples does not show a significant variation, considering the error values. ...

... Closure levels were observed to be consistently slightly lower (no more than 0.05 difference) than corresponding opening levels and thus not presented in the data, although the difference is dependent on the prominence of reversed plasticity-largest difference was observed in the beginning of an analysis with a low strength material and fully reversed loading, where initial opening level was roughly op ∕ max = −0.3 ( Fig. 18(d)) and corresponding closure level cl ∕ max = −0.5. Recently in [52], the difference between opening and closing levels was also pointed out to depend on the crack tip residual stress state; smaller deviation from the crack growth master curve, as suggested by the similitude concept, was achieved using the closing levels for various conditions. Fig. 8 presents contour plots for opening levels op ∕ max on the surface generated by the propagating crack. ...

... In recent years, a lot of studies on TMF characteristics have been reported for several types of materials, such as 9% Cr steel [14][15][16][17], nickel-base alloys [18][19][20], titanium-aluminide alloys [21,22] etc. In addition, with the rapid development and broad application of 300 series austenitic stainless steel, the TMF behaviour of 300 series austenitic stainless steel has become a hot spot in the field of high-temperature structural integrity [23][24][25]. ...

... These simulation techniques have been applied for additively manufactured Ti alloys [8,32,6,33,14], FCC metals [34,35,36,13,37,33,38] or several superalloys [39,40,41,40,42]. In the case of additively manufactured Hastelloy-X very few models have been proposed to date, and the published studies [43,44] are focused on macroscopic anisotropic elasto-plasticity, not accounting in a direct manner the effect of microstructure. ...

... However, some studies reported the mitigation methodologies for porosity, surface roughness and residual stresses effects on the fatigue lives by optimizing the processing parameters [20], heat treatment [21] and powder composition [3]. With respect to the specimen orientation, the fatigue life of vertically built specimens has been found to be inferior to horizontally built parts when loaded under stress control [22,16,12,23,19]. On the contrary, under strain-controlled loading, some studies [10] show the opposite effect, vertically built samples having a superior fatigue performance than horizontally built samples. ...

... Therefore, thermomechanical fatigue (TMF) develops when cyclic mechanical strain and thermal strain co-occur [6][7][8][9]. In consequence, the TMF behaviour of materials has attracted considerable interest and has been considered to be an important factor in the field of the high-temperature structural integrity of components [10][11][12][13]. ...

... The reversed set-up, with maximum temperature during tension and minimum temperature in compression, is termed in-phase (IP) TMF. The potential and behaviour of A-ASS in power plant applications with TMF characteristics have, to some extent, already been evaluated [12][13][14][15][16][17][18]. From the studies of Nagesha et al. and Kumar et al. [12,13] (∆T = 300-650 • C), Petras et al. [14,15] and Polák et al. [16] (∆T = 250-700 • C), the IP-TMF condition was generally associated with grain boundary cracking originating from creep damage and oxidation due to the depletion of chromium caused by precipitation of chromium carbides. ...

... To ensure that the stress value of steam turbine rotor is less than the yield limit value of rotor material is the decisive factor to shorten the start-up time of steam turbine unit. From a few years ago to now, people's quality of life has been signi icantly improved, the power grid capacity has also been signi icantly improved, so the peak value of the power grid is also increasing [2]. Frequent peak shaving operation refers to frequent startup and shutdown of steam turbine units. ...