Understanding the impact of grain structure in austenitic stainless steel from a nanograined regime to a coarse-grained regime on osteoblast functions using a novel metal deformation–annealing sequence

Multifunctional Properties of Bulk Nanostructured Metallic Materials

“…This was demonstrated on a 316L stainless steel processed using the phase reversion concept that allows to obtain grain size from nanograined to coarse-grained structure [270]. Grain refinement from 22 μm to 320 nm resulted in the increase of yield strength from 350 to 768 MPa without any significant reduction in ductility.…”

“…However, it should be noted that the studied compacts were not fully dense and had porosity of 5-10 %, so, strictly speaking, the reported observations cannot be related only to the grain size effect. Later, research activities were more focused on fully dense bulk nanostructured metallic biomaterials produced via SPD processing [260][261][262][263][264][265][266][267][268][269][270], though nanostructuring of pure Ti via ECAP for application in medical implants was patented already in 2002 [271]. It was demonstrated that apart from ultrahigh strength (see Sect.…”

“…The nanostructured stainless steels also provide enhanced cell growth and proliferation [268,270]. This was demonstrated on a 316L stainless steel processed using the phase reversion concept that allows to obtain grain size from nanograined to coarse-grained structure [270].…”

“…Nanostructured metals (Mg and Fe) and based on them porous composites have a great potential to satisfy all these requirements, with their biodegradability and bioresorbability (achieved by combining biodegradable magnesium and iron Fig. 3.41 Fluorescence micrographs illustrating the effect of grain size in the 316L stainless steel on a preosteoblast cell nuclei stained with Hoechst 33258 after 1-h culture; b, c immunocytochemistry of fibronectin expressed by preosteoblasts after incubation for 48 h; d the organization and assessment of vinculin focal contacts; and e actin stress fibers of preosteoblasts cultured for 48 h. The micrographs are reproduced from [270] with the permission from the publisher components), high strength (achieved by nanostructuring as well as iron reinforcement/skeleton in Mg), controlled corrosion behavior (by choosing the Mg/Fe distributions), required elastic modulus, enhanced possibility of bone adaptation, and controlled drug release option (achieved by macro-and microporosity) [283][284][285][286][287].…”

“…Data are mean ± SD (n = 3, p < 0.05), indicating a statistical difference from coarse-grained to nanograined 316L stainless steel with various grain sizes (22 μm, 2.1 μm, 757 nm, 538 nm, 320 nm). The figure is reproduced from [270] with the permission from the publisher Mg alloys with set of required multifunctional properties for biomedical applications. Again, attention should be paid to the crystallographic texture developed during SPD processing, since the control of texture in Mg and Mg-based implants could be used to tailor the mechanical properties and the resorption rates without compromising cytocompatibility [291].…”