The combination of high strength and good ductility are very desirable for advanced structural and functional applications. However, measures to enhance strength typically lead to ductility reduction due to their inverse correlation, nano-grained structures for an instance. Bi-modal grain structure is promising in this regard, but its realization is limited by multiple complex processing steps. Here, we demonstrate a facile single-step processing route for the development of bimodal grain structure in austenitic stainless steel, SS316L. The bimodal structure comprised of fine martensite grains (<500 nm) sandwiched between coarse austenite grains (~10 µm). The dual-phase bimodal structure demonstrated higher yield strength (~620 MPa) compared to ultra-fine grain structure (~450 MPa) concurrent with high uniform tensile ductility (~35%). These exceptional properties are attributed to unique dual-phase, bimodal grain structure which delayed the onset of plastic instability resulting in higher strength as well as larger uniform elongation and work-hardening rate. Our approach may be easily extended to a wide range of material systems to engineer superior performance.

ObjectiveCardiac surgical operations involving extracorporeal circulation may develop severe inflammatory response. This severe inflammatory response syndrome (SIRS) is usually associated with poor outcome with no predictive marker. Red cell distribution width (RDW) is a routine hematological marker with a role in inflammation. We aim to determine the relationship between RDW and SIRS through our study.MethodsA total of 1250 patients who underwent cardiac surgery with extracorporeal circulation were retrospectively analyzed out of which 26 fell into the SIRS criteria and 26 consecutive control patients were taken. RDW, preoperative clinical data, operative time and postoperative data were compared between SIRS and control groups.ResultsThe demographic profile of the patients was similar. RDW was significantly higher in the SIRS versus control group (15.5±2.0 vs. 13.03±1.90), respectively with P value <0.0001. There was significant mortality in the SIRS group, 20 (76.92%) as compared to 2 (7.6%) in control group with a P value of <0.005. Multiple logistic regression analysis revealed that there was significant association with high RDW and development of SIRS after extracorporeal circulation (OR for RDW levels exceeding 13.5%; 95% CI 1.0-1.2; P<0.05).ConclusionIncreased RDW was significantly associated with increased risk of SIRS after extracorporeal circulation. Thus, RDW can act as a useful tool to predict SIRS in patients undergoing cardiac surgery with extracorporeal circulation. Hence, more aggressive measures can be taken in patients with high RDW to prevent postoperative morbidity and mortality.

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Bimodal microstructures in metals are attractive because they help in achieving high strength and good ductility simultaneously thereby circumventing the strength‐ductility paradox. However, there are few reports and limited understanding of the surface degradation behavior of bimodal alloys. Here, the authors report on the exceptional corrosion resistance of bimodal stainless steel developed using a simple single‐step processing route. The microstructure of bimodal steel comprises of fine martensite (≈200–400 nm) in a matrix of coarse austenitic grains (≈10 μm). The bimodal steel shows significantly lower corrosion rate of 0.001 mm/year in 3.5 wt% NaCl solution compared to 0.088 mm/year for commercially available SS316L stainless steel. The exceptional corrosion behavior of bimodal steel is attributed to favorable electronic properties of its passive layer. Formation of a depletion zone in the passive layer and higher chromium fraction limits the charge transport across metal‐oxide‐solution interface. The current microstructural design strategy is potentially transformative for developing high‐performance structural materials with superior corrosion resistance.

Mitral PPM is an independent predictor of persistent PAH after MVR along with associated morbidity and reduced survival.