On the mechanics of cold die compaction for powder metallurgy

Al-Qureshi, H. A.; Galiotto, Alexandre; Klein, Aloı́sio Nelmo

doi:10.1016/j.jmatprotec.2004.08.009

Cited by 47 publications

(33 citation statements)

References 10 publications

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“…A densidade relativa alcançou um valor máximo de 64% para a amostra de 1 hora comparada a 56% da amostra de 64 horas. O pó moído por 1 hora pode estar com granulometria mais variada, onde os grãos menores preenchem espaços vazios deixados pelos maiores, aumentando assim o empacotamento das partículas e a densidade a verde, como indicado na literatura [18].…”

Section: Compressibilidade Das Misturasunclassified

Efeito da moagem de alta energia na morfologia e compressibilidade do compósito WC-Ni

Torres¹,

Shaeffer²

2010

Matéria (Rio J.)

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RESUMOEste trabalho tem por objetivo a investigação do efeito da moagem de alta energia sobre a morfologia, tamanho de partícula e compressibilidade do compósito WC-Ni. O metal duro é um material compósito utilizado em diversas áreas de usinagem, mineração e construção civil, podendo ser aplicado diretamente em componentes de equipamentos de perfuração de petróleo e gás. A moagem do metal duro WC-20Ni, partindo dos pós de WC e Ni, foi realizada para tempos de moagem de 1, 2, 4, 8, 16, 32 e 64 horas. A fim de observar a influência do tempo de moagem sobre a microestrutura, empregaram-se as técnicas de microscopia eletrônica de varredura e granulometria a laser. Esta avaliação permitiu observar o comportamento morfológico e a interação entre os componentes do material produzido. Os resultados mostram que o tempo de moagem produz a redução do tamanho das partículas seguida de formação de aglomerados com tamanhos menores do que os componentes utilizados na obtenção dos compósitos. Palavras-chaves:Moagem de alta energia, compósito WC-Ni, compressibilidade, morfologia. Effect of high energy milling on the morphology and compressibility of WC-Ni composite powder ABSTRACTThe purpose of this work is to analyze the effect of high energy milling on the morphology, particle size and compressibility of WC-Ni composite. The hard metal is a composite material used in several areas of machining, mining and construction and can be applied directly to components of drilling equipment for oil and gas. The milling of hard metal WC-20Ni, from the WC and Ni powders, was performed for milling times of 1, 2, 4, 8, 16, 32 and 64 hours. Scanning electron microscopy and laser granulometry were used to follow the influence of milling time on the microstructure. This evaluation allowed to observe the morphological behavior and interaction between the components of the material produced. The results show that the milling time produces a reduction of particle size followed by particle agglomeration with sizes smaller than the components used in the preparation of composites.Keywords: High energy milling, WC-Ni composite, compressibility, powder morphology. INTRODUÇÃOA metalurgia do pó é, às vezes, uma rota alternativa na produção de produtos e, outras vezes, a única alternativa de produção, como é o caso do compósito metal duro. Metais duros são materiais compósitos com elevada dureza e relativamente elevada tenacidade à fratura, que oferecem alta resistência ao desgaste. Eles são utilizados em ferramentas de corte industrial e outras aplicações onde alta resistência ao desgaste é necessária [1].O metal duro é composto por duas fases: a fase dura e frágil formada por carbeto (WC, TiC, TiCN), e a fase ligante (Co, Ni, Fe). Ambas as fases podem ser modificadas com o objetivo de alcançar as propriedades finais desejadas [2]. A quantidade de ligante está diretamente relacionada com as propriedades do metal duro e o aumento do teor de ligante diminui a dureza do material, elevando sua tenacidade à fratura [3].

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Section: Compressibilidade Das Misturasunclassified

Efeito da moagem de alta energia na morfologia e compressibilidade do compósito WC-Ni

Torres¹,

Shaeffer²

2010

Matéria (Rio J.)

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“…It is based on the authors' previously published theoretical model to predict the green density porosity distributions (Al-Qureshi et al, 2005).…”

Section: Nomenclaturementioning

confidence: 99%

“…Previously published works in general, rely on empirical or semi-theoretical expressions to relate the green density as a function of process parameters. Recently, the authors have published an analysis of the cold die compaction of powder materials based on the axi-symmetric solution of large deformation, but it did not elaborate on other important parameters (Al-Qureshi et al, 2005). Therefore, the aim of this paper is to incorporate these parameters, such as, work hardening, size of particles, internal friction, and porosity and also to examine their effect on the distribution of densification of powder during the compaction process.…”

Section: Theoretical Considerationsmentioning

confidence: 99%

Analyses of the fundamental parameters of cold die compaction of powder metallurgy

Al-Qureshi

Soares

Hotza

et al. 2008

Journal of Materials Processing Technology

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“…Various distinct shaping techniques are in use for the consolidation of the powders (or powder feedstock's) in finished sintered parts. Due to economic reasons, the currently most used ones are axial die pressing (powder compaction) 4,5 and powder injection molding [6][7][8] . The choice depends on a series of aspects including shape complexity of the part, quality needed for the final material (properties), and characteristics of available powders for feedstock preparation, among others.…”

Section: Introductionmentioning

confidence: 99%

Sinterability and microstructure evolution during sintering of ferrous powder mixtures

et al. 2013

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The present work is focused on ferrous powder metallurgy and presents some results of a development of a suitable masteralloy for use as an additive to iron powder for the production of sintered steels. The masteralloy was produced by melting a powder mixture containing approximately Fe + 20% Ni + 20% Mn + 20% Si + 1% C (wt%), in order to obtain a cast billet that was converted into fine powder by crushing and milling. It was observed presence of SiC in the masteralloy after melting that is undesirable in the alloy. Si element should be introduced by using ferrosilicon. Sintered alloys with distinct contents of alloying elements were prepared by mixing the masteralloy powder to plain iron powder. Samples were produced by die compaction of the powder mixtures and sintering at 1200 °C in a differential dilatometer in order to record their linear dimensional behaviour during heating up and isothermal sintering, aiming at studying the sinterability of the compacts. Microstructure development during sintering was studied by SEM, XRD and microprobe analyses.

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On the mechanics of cold die compaction for powder metallurgy

Cited by 47 publications

References 10 publications

Efeito da moagem de alta energia na morfologia e compressibilidade do compósito WC-Ni

Efeito da moagem de alta energia na morfologia e compressibilidade do compósito WC-Ni

Analyses of the fundamental parameters of cold die compaction of powder metallurgy

Sinterability and microstructure evolution during sintering of ferrous powder mixtures

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