How stainless steel breaks down under pressure—and what it means for critical infrastructure
Researchers have identified how atoms migrate along grain boundaries in 304L stainless steel when subjected to prolonged stress, a process that weakens the material over time. The finding could help engineers design longer-lasting components for power plants, pipelines, and aerospace systems—where unexpected failure carries enormous costs.
Originaltitel: Comments on Creep-induced elemental redistribution at grain boundaries of 304L stainless steel–An experimental evidence for diffusional creep mechanisms
<p>Creep experiments on 304 austenitic steels at high temperatures and low stresses (750°C, 2–15 MPa), conducted by Kombaiah et al. (Acta Materialia 121137, 2025), reported a stress exponent close to 1 and attributed the mechanism to diffusional creep. It has recently been found that diffusional creep and primary dislocation creep are competing mechanisms in the high-temperature, low-stress regime with a stress exponent of approximately 1. For this reason, the data of Kombaiah et al. are reanalysed in this note. Their data show a distinct primary creep stage, which is well-described by the ϕ (phi) model. Moreover, the primary creep curve and associated creep rates are successfully predicted by a basic dislocation model. These findings provide strong evidence that primary dislocation creep is the controlling creep mechanism. Furthermore, the Coble grain boundary diffusional creep model significantly overestimates the observed creep rates in austenitic stainless steels, further challenging the diffusional creep interpretation.</p>