5 research outputs found
Development of new Ni-Mn-Ga based high temperature shape memory alloys.
146 p.Desarrollo de aleaciones con memoria de forma, tanto como convencional, SMAs, como magnética, FSMAs, para aplicaciones a alta temperatura. Estudio de las propiedades magnéticas, estructurales y mecánicas de las aleaciones tipo Heusler con base Ni2MnGa. En esta tesis se desarrollaron SMAs monocristalinos, con actuación a 670 K, mostrándose deformaciones del 4%. Se estudiaron sistemas de FSMAs multicomponentes policristalinos de Ni-Mn-Ga-Fe-Co-Cu, y se determinándose la relación existente entre la composición y las distintas propiedades. De entre los sistemas estudiados se obtuvieron 3 composiciones que mostraban temperaturas de transformación por encima de los 373 K y temperaturas de Curie mayores de 423 K. El estudio de neutrones realizado en las muestras multicomponentes ha permitido dilucidar el orden atómico presente en estas aleaciones y correlacionarlo con el aumento de la imanación de saturación mediante la variación de las interacciones entre manganesos. Por último, se ha analizado la relación entre la composición y la estructura con los parámetros críticos para la obtención de memoria de forma magnética, en monocristales de FSMAs de alta temperatura
Effect of Heat Treatment on the Microstructure and Hardness of Ni-Based Alloy 718 in a Variable Thickness Geometry Deposited by Powder Fed Directed Energy Deposition
Feature addition to existing parts is a trending application for Directed Energy Deposition (DED) and can be used to add complex geometry features to basic forged geometries with the aim to reduce and simplify the number of processing steps as machining and assembling. However, the mechanical properties of as-deposited Inconel 718 fabricated by Powder-fed Directed Energy Deposition (Powder-fed DED) are far lower than the relevant specifications, making it necessary to apply different heat treatment with the purpose of improving deposited material performance. In addition, the effects of heat treatments in both variable thickness deposited geometry and forge substrate have not been studied. In this study, the effect of heat treatment within the Aerospace Materials Specifications (AMS) for cast and wrought Inconel 718 on the microstructure and hardness of both the Ni-Based Alloy 718 deposited geometry and substrate are analyzed in different parts of the geometry. The microstructure of all samples (as-deposited and heat-treated) is analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS), confirming the formation of aluminum oxides and titanium nitrides and carbonitrides in the deposited structure.This research was funded by the vice-counsel of technology, innovation and competitiveness of the Basque Government (Eusko Jaurlaritza) under the ELKARTEK Program, QUALYFAM and EDISON projects, grant number KK-2020/00042 and KK-2022/00070, respectively
Development of new Ni-Mn-Ga based high temperature shape memory alloys.
146 p.Desarrollo de aleaciones con memoria de forma, tanto como convencional, SMAs, como magnética, FSMAs, para aplicaciones a alta temperatura. Estudio de las propiedades magnéticas, estructurales y mecánicas de las aleaciones tipo Heusler con base Ni2MnGa. En esta tesis se desarrollaron SMAs monocristalinos, con actuación a 670 K, mostrándose deformaciones del 4%. Se estudiaron sistemas de FSMAs multicomponentes policristalinos de Ni-Mn-Ga-Fe-Co-Cu, y se determinándose la relación existente entre la composición y las distintas propiedades. De entre los sistemas estudiados se obtuvieron 3 composiciones que mostraban temperaturas de transformación por encima de los 373 K y temperaturas de Curie mayores de 423 K. El estudio de neutrones realizado en las muestras multicomponentes ha permitido dilucidar el orden atómico presente en estas aleaciones y correlacionarlo con el aumento de la imanación de saturación mediante la variación de las interacciones entre manganesos. Por último, se ha analizado la relación entre la composición y la estructura con los parámetros críticos para la obtención de memoria de forma magnética, en monocristales de FSMAs de alta temperatura
Role of Fe addition in Ni–Mn–Ga–Co–Cu–Fe ferromagnetic shape memory alloys for high-temperature magnetic actuation
The p.P888L SAP97 polymorphism increases the transient outward current (Ito,f) and abbreviates the action potential duration and the QT interval.
Synapse-Associated Protein 97 (SAP97) is an anchoring protein that in cardiomyocytes targets to the membrane and regulates Na+ and K+ channels. Here we compared the electrophysiological effects of native (WT) and p.P888L SAP97, a common polymorphism. Currents were recorded in cardiomyocytes from mice trans-expressing human WT or p.P888L SAP97 and in Chinese hamster ovary (CHO)-transfected cells. The duration of the action potentials and the QT interval were significantly shorter in p.P888L-SAP97 than in WT-SAP97 mice. Compared to WT, p.P888L SAP97 significantly increased the charge of the Ca-independent transient outward (Ito,f) current in cardiomyocytes and the charge crossing Kv4.3 channels in CHO cells by slowing Kv4.3 inactivation kinetics. Silencing or inhibiting Ca/calmodulin kinase II (CaMKII) abolished the p.P888L-induced Kv4.3 charge increase, which was also precluded in channels (p.S550A Kv4.3) in which the CaMKII-phosphorylation is prevented. Computational protein-protein docking predicted that p.P888L SAP97 is more likely to form a complex with CaMKII than WT. The Na+ current and the current generated by Kv1.5 channels increased similarly in WT-SAP97 and p.P888L-SAP97 cardiomyocytes, while the inward rectifier current increased in WT-SAP97 but not in p.P888L-SAP97 cardiomyocytes. The p.P888L SAP97 polymorphism increases the Ito,f, a CaMKII-dependent effect that may increase the risk of arrhythmias.This work was funded by: Ministerio de Economía y Competitividad [SAF2017-88116-P; BFU2016-75144-R (JAB)]; Comunidad Autónoma de Madrid [B2017/BMD-3738; 2018-T2/BMD-10724 (JC)], Comunidad Autónoma de Madrid and Universidad Complutense de Madrid [PR65/19-22358 (JC)] European Structural and Investment Funds (ESIF); Instituto de Salud Carlos III [PI16/00398]; The Spanish Society of Cardiology.S