Enhanced mechanical behavior of a nanocrystallised stainless steel and its thermal stability

High Strength Nanocrystallized Multilayered Structure Obtained by SMAT and Co-Rolling

“…In previous studies, microstructural characterizations of SMATed 316L austenitic stainless steel have been carried out [2,3,4,6]. Transmission Electron Microscopy observations (TEM) performed near the extreme top surface of the specimens have thus shown grains in the nanometre range characterized by highly random crystallographic orientations and exhibit an average grain size of approximately 20nm.…”

“…In order to achieve an ultrafine grain structure, several severe plastic deformation (SPD) processes have been proposed, such as accumulative roll-bonding (ARB), equal channel angular pressing (ECAP), high pressure torsion (HPT) or mechanical milling. In addition, numerous studies have shown that recently developed Surface Mechanical Attrition Treatment (SMAT) may induce a grain refinement up to the nanometre scale in the top surface layer of metallic materials, based on mechanisms of severe plastic deformation [1][2][3][4][5]. In the present work, a method is presented combining this SMAT process and the co-rolling process for the development of a semi-massive multilayer bulk structure with improved yield and ultimate tensile strengths, while conserving an acceptable elongation to failure.…”

“…Furthermore, complementary tensile tests highlight the effect of SMAT on the mechanical response of treated and co-rolled samples. The microstructures of SMATed but undeformed tensile specimens have been analysed previously by Transmission Electron Microscopy (TEM) [3,4]. Finally, Scanning Electron Microscopy (SEM) micrographs show how the laminate samples are torn apart during tensile tests.…”

Martensite and bainite in nanocrystalline steels: understanding, design and applications

“…In recent years, novel surface nanocrystallisation approaches have been developed to synthesise nanostructured surface layers on metallic materials by mechanical means, such as by surface mechanical attrition treatment (SMAT) and surface mechanical grinding treatment (SMGT) [6]. With these techniques, microstructures within a surface layer as thick as few hundred micrometres can be effectively refined, forming a nano-grained gradient structure.…”

Nanostructuring Combined Frictional-Thermal Treatment of 12kh18n10t Austenic Steel

“…Кроме того, известно, что опти-мальное сочетание прочности и пластичности наност-руктурированных и ультрамелкозернистых сталей мо-жет достигаться комбинированными обработками, пре-дусматривающими после деформационного воздейст-вия проведение дополнительной термической обработ-ки [14][15][16]. Например, у деформированных аустенит-ных сталей 316L и AISI 301LN комбинация повышен-ных характеристик прочности и пластичности отмеча-ется соответственно после кратковременного (10 мин) отжига в температурном интервале 300-500 °С [17] и после отжига при 650 °С в течение 30 мин [18]. Для метастабильных аустенитных сталей, претерпевающих деформационное мартенситное γ→α'-превращение, улучшение комплекса механических свойств после на-грева до температур 600 °С и более связывают с разви-тием обратного α'→γ-превращения мартенсита дефор-мации и формированием субмикро-и нанокристалли-ческих аустенитных структур [19][20][21][22].…”