Caracterização macro e microestrutural de uma junta soldada de revestimento com superligas / Macro and microstructural characterization of a welded joint with superalloys

As superligas são usadas em aplicações que requerem alto desempenho mesmo sob severas condições de trabalho. Nesse grupo, as mais comuns são as superligas à base de níquel, em que se destaca o Inconel 718. A resistência mecânica do Inconel 718 é graças à precipitação das fases endurecedoras ?’ (Ni3Al,Ti) e ?’’ (Ni3Nb) na matriz austenítica. No entanto, em exposição a temperaturas maiores que 650°C por longo período de tempo, pode levar ao coalescimento dos precipitados resultando na diminuição da resistência mecânica. Outra situação indesejável é a ocorrência de oxidação intergranular – Oxidation Assisted Integranular Cracking (OAIC). Esse fenômeno reduz drasticamente a ductilidade, levando o material rapidamente à fratura frágil quando submetido à tensão. Nesse contexto, o objetivo do presente trabalho é realizar uma soldagem com um revestimento que tenha como característica melhorar a resistência à oxidação a altas temperaturas do Inconel 718. Para atingir tal objetivo, amostras da superliga foram soldadas pelo processo laser cladding com pó de Ni-Cr-Al-Hf-Y. Uma análise macro e microestrutural foi conduzida. Resultados mostraram que a solda realizada foi totalmente aderente e íntegra. A microestrutura da ZTA apresentou intensa precipitação de fase ? e a da ZF finas dendritas equiaxiais predominantemente

Mechanical Characterization Of Ti-12mo-13nb Alloy For Biomedical Application Hot Swaged And Aged

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Beta titanium alloys were developed for biomedical applications due to the combination of its mechanical properties including low elasticity modulus, high strength, fatigue resistance, good ductility and with excellent corrosion resistance. With this perspective a metastable beta titanium alloy Ti-12Mo-13Nb was developed with the replacement of both vanadium and aluminum from the traditional alloy Ti-6Al-4V. This paper presents the microstructure, mechanical properties of the Ti-12Mo-13Nb hot swaged and aged at 500 degrees C for 24 h under high vacuum and then water quenched. The alloy structure was characterized by X-ray diffraction and transmission electron microscopy. Tensile tests were carried out at room temperature. The results show a microstructure consisting of a fine dispersed a phase in a beta matrix and good mechanical properties including low elastic modulus. The results indicate that Ti-12Mo-13Nb alloy can be a promising alternative for biomedical application.182812Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)UniFOAConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Mechanical characterization of Ti-12Mo-13Nb alloy for biomedical application hot swaged and aged

Beta titanium alloys were developed for biomedical applications due to the combination of its mechanical properties including low elasticity modulus, high strength, fatigue resistance, good ductility and with excellent corrosion resistance. With this perspective a metastable beta titanium alloy Ti-12Mo-13Nb was developed with the replacement of both vanadium and aluminum from the traditional alloy Ti-6Al-4V. This paper presents the microstructure, mechanical properties of the Ti-12Mo-13Nb hot swaged and aged at 500 °C for 24 h under high vacuum and then water quenched. The alloy structure was characterized by X-ray diffraction and transmission electron microscopy. Tensile tests were carried out at room temperature. The results show a microstructure consisting of a fine dispersed α phase in a β matrix and good mechanical properties including low elastic modulus. The results indicate that Ti-12Mo-13Nb alloy can be a promising alternative for biomedical application.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Different Cell Death Responses Induced By Eupomatenoid-5 In Mcf-7 And 786-0 Tumor Cell Lines

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Natural products remain an important source of new drugs, including anticancer drugs. Recently, our group reported the anticancer activity of eupomatenoid-5 (eup-5), a neolignan isolated from Piper regnellii (Miq.) C. DC. var. regnellii leaves. In vitro studies demonstrated that MCF-7 (breast) and 786-0 (kidney) were among the cancer cell lines most sensitive to eup-5 treatment. The current results demonstrate that mitochondrial membrane depolarization and generation of reactive oxygen species are implicated in eup-5-mediated cytotoxic effects on these cancer cells lines. In MCF-7 cells, eup-5 led to phosphatidylserine externalization and caspase activation, whereas the same did not occur in 786-0 cells. Scanning electron microscopy revealed a reduction of microvilli density, as well as cell morphology alterations. Moreover, treated MCF-7 cells exhibited well-characterized apoptosis alterations, while treated 786-0 cells exhibited characteristics of programmed necroptosis process. These findings support the possibility that different mechanisms may be targeted by eup-5 in cell death response. (C) 2015 Elsevier Ltd. All rights reserved.29510261033Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)National Cancer Institute-Frederick, MA, USAFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPESP [2010/50232-7

Effect of hot swaging on microstructure and properties of aged Ti-10Mo-20Nb alloy

Mechanical properties of metastable β-Ti alloys are highly dependent on the final microstructure, which is controlled by the thermomechanical processing. These alloys are used for biomedical applications and require a high mechanical strength as well as a low Young’s modulus to avoid stress shielding. Previous work on the development of cold swaged Ti-10Mo-20Nb alloy showed that the best compromise strength and Young’s modulus was obtained when the forming is followed by an aging heat treatment at 500 °C. In this work, Ti-10Mo-20Nb alloy was hot swaged and aged at 500 °C for 10 min, 4h and 24h. The microstructure was analyzed by X-ray diffraction, optical microscopy and transmission electron microscopy. Mechanical characterization was based on Vickers microhardness tests and Young’s modulus measurements. Aging at 500°C for 10 min after hot swaging resulted in a nearly 100% β phase microstructure while aging at 500°C for 4h or 24h led to a bimodal microstructure consisting on α precipitates dispersed in the β matrix. The higher hardness to Young’s modulus ratio was obtained for the sample aged at 500 °C for 4h. This value was higher than those obtained for the Ti-6Al-4V alloy and commercially pure Ti.SCOPUS: cp.kinfo:eu-repo/semantics/publishe

Ultrastructural Assessment Of 2-(acridin-9-ylmethylene)-n-phenylhydrazinecarbothioamide Activity On Human Breast Adenocarcinoma Cells

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The aim of the present study was to investigate ultrastructural changes induced by (Z)-2-(acridin-9-ylmethylene)-N-phenylhydrazinecarbothioamide (APHCA) treatment on human breast adenocarcinoma cancer cells MCF-7, besides the evaluation of phosphatidylserine externalization and DNA fragmentation in treated cells. Cell viability analysis demonstrated concentration and time-manner cytotoxicity. Treated MCF-7 cells did not expose phosphatidylserine residues to the external plasma membrane surface and DNA fragmentation was not visualized by electrophoresis. Light microscopy showed compromised cell density and presence of vacuolization after APHCA treatment with 60 mu M. Scanning and transmission electron microscopies revealed hallmarks of autophagy, namely the presence of membrane bebbling and autophagosomes, besides shrunken cells and cell debris in treated MCF-7 cells. However, more specific tests such as the quantification of mammalian autophagy proteins are necessary to determine the kind of death that is trigged by APHCA. (C) 2016 Elsevier Ltd. All rights reserved.90114122CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Brazil)FACEPE (Fundo de Amparo a Ciencia e Tecnologia de Pernambuco, Brazil)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

New Spiro-acridines: Dna Interaction, Antiproliferative Activity And Inhibition Of Human Dna Topoisomerases

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Two new spiro-acridines were synthesized by introducing cyano-N-acylhydrazone between the acridine and phenyl rings followed by spontaneous cyclization. The final compounds (E)-1'-(benzylideneamino)-5'-oxo-1',5'-dihydro-10H-spiro[acridine-9,2'-pyrrole]-4'-carbonitrile (AMTAC-01) and (E)-1'-((4-methoxybenzylidene)amino)-5'-oxo-1',5'-dihydro-10H-spiro[acridine-9,2'-pyrrole]-4'-carbonitrile (AMTAC-02) were evaluated for their interactions with calf thymus DNA, antiproliferative and human topoisomerase I and II alpha inhibitory activities. Both compounds presented ability to bind DNA. The binding constant determined by UV-vis spectroscopy was found to be 10(4)M(-1). Antiproliferative assay demonstrated that AMTAC-01 and AMTAC-02 were most active against prostate and melanoma tumor cell lines, respectively. The compound did not present Topo I inhibitory activity. However, both derivatives displayed topoisomerase IIa inhibitory activity comparable to amsacrine, and AMTAC-02 was more potent than AMTAC-01 with methoxy substituent group on phenyl ring. This study demonstrates that the new derivatives are promising molecules with topoisomerase II alpha inhibitory and antiproliferative activities. (C) 2016 Elsevier B.V. All rights reserved.92467475CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Brazil)CAPES (Fundacao Coordenacao de Aperfeicoamento de Pessoal de Ensino Superior, Brazil)FACEPE (Fundo de Amparo a Ciencia e Tecnologia de Pernambuco, Brazil) [APQ-0903-4.03/15]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES