The development of hardness homogeneity in aluminum and an aluminum alloy processed by ECAP

Xu, Cheng; Langdon, Terence G.

doi:10.1007/s10853-006-0899-5

Cited by 83 publications

(37 citation statements)

References 27 publications

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“…The dislocation hardening is then converted with the grain refinement strengthening and finally reached the quite saturation level at the final passes. It is well known that this can be occurred in UFG materials fabricated by the SPD methods [3,18,19]. As known, microstructural features and grain size may play an important role in the corrosion behavior of materials.…”

Section: Figurementioning

confidence: 99%

Electrochemical behavior of equal channel angular pressed titanium for biomedical application

Göde

Attarilar

Eghbali

et al. 2015

AIP Conference Proceedings

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Abstract. Equal channel angular pressing method is one of the prominent severe plastic deformation techniques to obtain ultrafine grained and even nanostructured metals and alloys by imposing intense plastic strain. As known, pure titanium can be a suitable candidate for biomedical applications because it does not release any toxic ions into the body fluids and also, its biocompatibility properties. The present investigation deals the corrosion behavior of commercial pure titanium before and after ECAP process up to 10 passes by route B C at the 250 °C in the 0.9% NaCl solution. The electrochemical results revealed that the corrosion resistance of titanium sample is improved by adding pass number because of the fabrication of passive oxide layer on the surface of the material. It is found that about 92% reduction at the corrosion rate magnitude and also, approximately 41% improvement at the hardness value have been achieved at the final pass as compared to the annealed condition. Furthermore, it is observed that the passive film on the surface of final pass sample is dense and integral with uniform structure, while the as-received one has some rarefactions and does not have very uniform surface.

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Section: Figurementioning

confidence: 99%

Electrochemical behavior of equal channel angular pressed titanium for biomedical application

Göde

Attarilar

Eghbali

et al. 2015

AIP Conference Proceedings

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“…1 shows an example for high purity (99.99%) aluminum where values of the Vickers microhardness, Hv, are plotted along a diameter of each billet with the diameter extending in the Z direction perpendicular to the horizontal with the bottom of the billet on the left and the top of the billet on the right: 25) separate data are shown for the asreceived unprocessed material and for samples processed by ECAP through 1 and 4 passes at 298 K where the repetitive passes were undertaken using route B C . These results show there is good homogeneity throughout the billet processed through 4 passes of ECAP except only at the bottom edge of the billet where lower hardness values are visible through a width of $2 mm.…”

Section: The Strengthening Introduced By Spd Processingmentioning

confidence: 99%

Using Severe Plastic Deformation for the Processing of Advanced Engineering Materials

Figueiredo

Langdon

2009

Mater. Trans.

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The processing of metals through the application of severe plastic deformation leads to significant grain refinement and provides an opportunity for achieving superior properties. The two procedures of equal-channel angular pressing (ECAP) and high-pressure torsion (HPT) are examined with emphasis on the mechanical properties at low and high temperatures and the nature of the grain refinement. It is demonstrated that grain refinement occurs relatively homogeneously in f.c.c metals through the formation of dislocation cells or subgrains and the evolution of these cells into an array of ultrafine grains separated by high angle boundaries. By contrast, grain refinement in h.c.p. metals such as magnesium is inhomogeneous and occurs through the nucleation of new grains along the initial grain boundaries due to the high stresses generated to activate multiple slip systems. Ultrafine-grained metals generally exhibit high strength but they may exhibit weakening if the processing conditions adversely affect the precipitate morphology. If the ultrafine grains are stable at high temperatures there is a possibility of achieving excellent superplastic properties.

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“…A ocorrência de regiões de menor dureza e a influência que o número de passes e a geometria da matriz exercem sobre esse fenômeno são frequentemente tratados na literatura, (13,15) associando diretamente a dureza com o grau de deformação localizada. A esse respeito, a Figura 7 mostra o mapeamento da microdureza Vickers sobre seções transversais na parte central das amostras 1X e 4X, indicando que o maior número de passes resulta em maior dureza e também em maior homogeneidade de deformação no volume da amostra.…”

Section: Resultsunclassified

Desenvolvimento Por Simulação Computacional E Análise Do Desempenho Real De Uma Matriz Para Extrusão Em Canal Angular

Springer¹,

Rubert²,

Sordi³

et al. 2013

TMM

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ResumoOs parâmetros geométricos críticos de uma matriz de Extrusão em Canal Angular (ECA) foram otimizados empregando o software Deform  . Em base ao resultados da simulação foi construída uma matriz ECA, dedicada ao processamento de placas de Al AA1050 com 7 mm de espessura. Do software foram obtidas as forças de prensagem e a distribuição da deformação equivalente na placa, após um e quatro passes. Essas forças simuladas foram comparadas com as reais, obtidas das curvas força versus deslocamento do punção, enquanto a distribuição da deformação equivalente foi validada por medidas de indentação Vickers. Ensaios de tração e a observação microestrutural das placas processadas mostram que o desempenho da matriz é amplamente satisfatório. Palavras-chave: Método de elementos finitos; Extrusão angular em canais; Deformação. DEVELOPMENT BY COMPUTATIONAL SIMULATION AND PERFORMANCE ANALYSIS OF AN EQUAL CHANNEL ANGULAR PRESSING DIE AbstractCritical geometric parameters of an Equal Channel Angular Pressing (ECAP) die suitable to plate processing were optimized by making use of the DEFORM™ software. Following the simulation a die was manufactured and employed in the processing of 7 mm thick Al AA 1050 plates. Software output included the pressing forces and the equivalent deformation distribution within the plates, after one and four ECAP passes. Calculated pressing forces against the punch displacement were compared with the actual forces, whilst the deformation distribution is validated by Vickers microhardness measurements. From tensile tests and microstructural observation of the processed plates the die performance was found quite satisfactory. Key words: Finite elements method; Equal channel angular pressing die; Deformation. INTRODUÇÃOMateriais microestrutura ultrafina, especificamente com tamanhos de grão entre 250 nm e 500 nm, exibem propriedades de grande interesse podendo ser obtidos por diversas tecnologias. Dentre estas se destaca o processo ECA, que permite a produção de materiais metálicos submicrocristalinos e com dimensões de interesse comercial. (1) Nessa tecnologia são inseridos tarugos com seção transversal quadrada ou circular em um canal formado por dois segmentos que fazem ângulo entre si, a deformação ocorrendo por cisalhamento simples. No projeto da matriz são críticos o ângulo entre os segmentos dos canais (Φ) e o ângulo de curvatura que denota o arco que faz a concordância dos mesmos (ψ) (Figura 1a). A maioria das investigações é realizada com Φ = 90° ou 120°, enquanto ψ tem uma variabilidade mais ampla. Os referidos ângulos determinam a severidade da deformação cisalhante, e a deformação equivalente (ε eq ) por passe é dada pela equação de Iwahashi: (2) http://dx

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The development of hardness homogeneity in aluminum and an aluminum alloy processed by ECAP

Cited by 83 publications

References 27 publications

Electrochemical behavior of equal channel angular pressed titanium for biomedical application

Electrochemical behavior of equal channel angular pressed titanium for biomedical application

Using Severe Plastic Deformation for the Processing of Advanced Engineering Materials

Desenvolvimento Por Simulação Computacional E Análise Do Desempenho Real De Uma Matriz Para Extrusão Em Canal Angular

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