The effects of interfacial conditions between the ferrite and martensite phases of an ultra-high strength dual phase (DP) steel sheet on its hydrogen embrittlement behavior has been investigated by a sustained tensile-loading test using as-quenched DP steel and tempered DP steel specimens. The yield ratio (yield stress/tensile strength) of the as-quenched DP steel is lower than that of the tempered DP steel. In the hydrogen thermal desorption analysis, the second desorption peak disappeared and the amount of absorbed hydrogen is decreased by tempering. Under the same applied stress in the sustained tensileloading test, the time to fracture shows no significant difference between the two steels, but the critical applied stress for fracture is increased by tempering. A quasi-cleavage fracture occurs at the fracture initiation site of both steels. On the cross section near the fracture surface, many cracks nucleate in blocks or packets in martensite and the interface between prior austenite grains, but no cracks is observed in ferrite grains. Under applied stress higher than the yield stress of the as-quenched DP steel, fracture occurs in a short time. A unique intergranular-like morphology is observed at the fracture initiation area, and the crack propagates in blocks or packets in martensite or along the interface between the ferrite and martensite phases while avoiding ferrite grains. Early fracture is inhibited by tempering. When excessive plastic deformation is applied before the sustained tensile-loading test, the time to fracture and critical applied stress of the as-quenched DP steel decreased slightly. The results of the present study indicate that the interfacial conditions between ferrite and martensite play important roles in crack propagation associated with hydrogen embrittlement of the DP steel.
Spontaneous ilio-iliac arteriovenous fistula (AVF) associated with aneurysms affecting the abdominal aortic and iliac arteries is a rare condition. The classical clinical symptoms of ilio-iliac AVF include high-output heart failure, abdominal pain, abdominal bruits and thrills, a pulsatile abdominal mass, and venous congestion symptoms (leg edema and hematuria). The prompt repair of AVF is necessary to restore the patient’s hemodynamics. We report a case in which a patient with aneurysms affecting the abdominal aortic and iliac arteries and an ilio-iliac AVF presented with high-output heart failure and leg ischemia and was successfully treated via endovascular stent graft repair.
Aortic mural thrombi of the ascending aorta are rare. If an aortic mural thrombus is dislodged, it can cause various embolic complications, which can sometimes be fatal. Although contrast-enhanced computed tomography (CT) and transesophageal echography are useful for diagnosing aortic mural thrombi, four-dimensional CT (4D-CT) is one of the most useful modalities for both diagnosis and treatment selection in such cases. 4D-CT can be used to evaluate the morphology and mobility of thrombi. Furthermore, it is minimally invasive. To the best of our knowledge, there have not been any reports about 4D-CT being used to depict an asymptomatic ascending aortic thrombus. We report a very unusual case, involving an aortic mural thrombus of the ascending aorta.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.