On the thermal coarsening and transformation of nanoscale oxide inclusions in 316L stainless steel manufactured by laser powder bed fusion and its influence on impact toughness

A synchrotron transmission X-ray microscopy study on precipitate evolution during solid-state thermal cycling of a stainless steel

“…The results show coarsening and phase transformations of these precipitates to more stable precipitates. In addition to these observations, faster coarsening kinetics of oxides were observed at the early stage of recrystallization due to grain boundary diffusion [5] accompanied by the following effects of the recrystallization on phase transformation [5]: MnSiO 3 to CrMn 2 O 4 for non-recrystallized grains and MnSiO 3 to Si-rich oxides in recrystallized grains.…”

“…Both techniques result in a hierarchical microstructure with physical and chemical heterogeneities across multiple length scales. Sub-micron sized oxide (i.e., MnSiO 3 , SiO 2 , and CrMn 2 O 4 ) [1][2][3][4][5] and non-oxide (i.e., sulfide such as MnS) [4,5] precipitates are among the smallest chemical and physical heterogeneities present in any as-built 316L. These precipitates play an important role in determining the mean free path of dislocations and may contribute to an increase in the yield strength of the material [1,2,6,7].…”

“…After building, AM parts are often heat-treated to obtain desired mechanical properties and reduce residual stresses. The evolution of these precipitates (oxide and non-oxides) was investigated during annealing treatments [2,5,6,13] by scanning and transmission electron microscopy (SEM and TEM, respectively). The results show coarsening and phase transformations of these precipitates to more stable precipitates.…”

Design of a Cost-Effective and Statistically Validated Test Specification with Selected Machine Elements to Evaluate the Influence of the Manufacturing Process with a Focus on Additive Manufacturing

“…The study aimed to determine the maximum notched impact energy of these components [29]. Deng et al (2019) performed a similar study and made a distinction between specimens that underwent heat treatment at 650 • C and those that did not [30]. In their study [31], Davies et al conducted comparable investigations wherein they analysed samples taken both horizontally and vertically in their original state, as well as after undergoing heat treatments at 700 • C and 900 • C. Komorasamy et al accomplished a comparative analysis of the behaviour of notched bar impact specimens extracted horizontally and vertically with respect to the direction of exposure as per DIN EN ISO 148 on Inconel 718 [23].…”

Critical role of slags in pitting corrosion of additively manufactured stainless steel in simulated seawater

“…MnS inclusions deplete local Cr concentrations or dissolve faster than the protective surface oxide, leaving regions of conventional 316L SS without protection against the chloride solution to become pit nucleation sites 26 . Notably, MnS inclusions do not form during LPBF due to elevated cooling rates 27 , 28 . Although this also applies to as-built surfaces, they often exhibit slightly lower pitting potential than post processed surfaces 21 – 23 .…”