Chinese scientists have found a way to overcome metal fatigue by transforming common stainless steel into a material strong enough for aerospace and other high-grade applications, according to a study in the peer-reviewed journal Science. A team from the Chinese Academy of Sciences’ Institute of Metal Research was able to alter the steel’s internal structure by twisting it like a towel to make it stronger and more resilient, the paper said. The modification not only more than doubled the material’s yield strength, it also increased its resistance to the accumulated damage of metal fatigue by a factor of up to 10,000. Potential applications may include undersea pipelines and engine components such as crankshafts and connecting rods that are exposed to pressure. Research team leader Professor Lu Lei said that there was no visible change to the material’s surface before and after processing, but “its internal structure had been transformed”. “The skeletal structure is just one three-hundredth the diameter of a human hair, but it plays a significant role when bearing pressure,” she said.
Traditional metal alloys can fracture or shatter under sudden external forces that exceed their yield strength, but they are also susceptible to fatigue when subjected to sustained pressure below this threshold. Over time, this can cause irreversible deformation as stress accumulates, leading to microscopic cracks, structural warping, and – in severe cases – catastrophic failure without warning. The phenomenon, known as cyclic creep, typically occurs in materials subjected to high temperatures or stresses over extended periods – such as in turbine blades, suspension bridge cables, and the boiler pipes in nuclear reactors, for example.
Increasing the strength of the materials used in these high-stress environments typically compromises their fatigue resistance, presenting a significant challenge to researchers in the field of materials engineering. Scientists have long sought to minimize the damage caused by creep through including material improvements, structural optimizations, and surface treatments. Through their innovative redesign of the metal’s crystal structure, Lu and her team have developed a processing method boosting the yield strength by 2.6 times and increasing the cyclic creep resistance by a factor of 100 to 10,000, the South China Morning Post reports.
