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Structure and properties of tool gradient materials reinforced with the WC carbides

Dobrzański L. A., Dołżańska B., Matula G.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 28, nr 1

35-38

EN

Purpose: The purpose of the paper is to describe sintered Tool Gradient Materials manufactured by powder metallurgy process. The Powder Metallurgy method has been chosen to manufacture tool gradient materials with high disproportion of cobalt matrix portion between core and surface layer. Design/methodology/approach: Forming methods were developed during the investigations for tungsten carbide and cobalt, making it possible to obtain materials wits five layers in their structure. Findings: High diversification of cobalt matrix portion in comparison to hard phases in subsequent layers of gradient materials leads to their deformation in as sintered state. In case of all gradient materials, mean hardness was equal about 1750 HV1. Whereas, hardness of lower cobalt matrix rich layers is about 1548 HV1 and increased up to 2154 HV1 for lower layer of material rich with hard carbide phases. The porosity decreases along with the carbon content in these layers. Practical implications: Material presented in this paper is characterized by very high hardness of the surface and relative ductility of core. TGM with a smooth changes of the cobalt phase in the material. Originality/value: The obtained results show the possibility of manufacturing of TGM on basis of different portion of cobalt reinforced with hard ceramics particles carried out in order to improve the abrasion resistance and ductility of tool cutting materials.

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Structure and properties of TGM manufactured on the basis of cobalt

Matula G., Dobrzański L. A., Dołżańska B.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 20, nr 1-2

151-154

EN

Purpose: It has been demonstrated in the paper structure and properties of tool gradient materials manufactured by powder metallurgy on the basis of cobalt. Design/methodology/approach: Light microscope, SEM, image analysis, microhardness tests, density examination. Findings: Basing on the investigations of the cemented carbides reinforced with different ceramics particles fabricated it was found of that density of sintered samples depend on reinforced particles, temperatures and atmosphere of sintering. Increasing of sintering temperature increase the density of sintering samples. Moreover the sintering under vacuum atmosphere produce samples with higher quality than using argon atmosphere and prevent of surface oxidation during sintering. Practical implications: The Powder Metallurgy gives the possibility to manufacturing tools gradient materials on the basis of cobalt which characterised very high hardness on the surface. Originality/value: In the paper the manufacturing of tool gradient materials on basis of cobalt reinforced with hard ceramics particles carried out in order to improve the tool cutting properties.

3

Influence of hard ceramic particles on structure and properties of TGM

Dobrzański L. A., Dołżańska B., Matula G.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 2

95-98

EN

Purpose: The Powder Metallurgy route has been chosen to fabricate tool gradient materials with high disproportion of cobalt matrix portion between core and surface layer. In the paper structure and properties of TGM have been shown. Design/methodology/approach: SEM, light microscope, microhardness tests, density examination. Findings: According to carried out researches it could be stated, that forming the gradient materials with highest amount of complex carbide (W,Ti)C 90-95%, using uniaxial unilateral pressing, could be possible after adding into each layer of mixes 2 % of paraffin lubricant. High diversification of cobalt matrix ratio in comparison to hard phases in subsequent layers of gradient materials leads to their deformation in as sintered state. In case of all gradient materials, mean hardness was equal about 1600 HV1. Whereas, hardness of lower cobalt matrix rich layers brought values about 1450 HV1 and increased up to 1800 HV1 for lower layer of material rich with hard carbide phases. Practical implications: Material presented in this paper is characterized by very high hardness of the surface and relative ductility of core. TGM is a smoothly varying distribution of phases element composition. Originality/value: In the paper the manufacturing of TGM on basis of different portion of cobalt reinforced with hard ceramics particles carried out in order to improve the abrasion resistance and ductility of tool cutting materials.

4

Influence of carbide (W, Ti)C on the structure and properties of tool gradient materials

Dobrzański L. A., Dołżańska B., Matula G.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 10

617-620

EN

Purpose: The goal of this work is to obtain the gradient materials based on the (W, Ti)C with high disproportion of cobalt matrix portion between core and surface layer. In this work is shown the structure and properties of Tool Gradient Materials (TGM). Design/methodology/approach: In presented study (W, Ti)C powder were mixed with cobalt powder. Prepared mixtures were heaped up, pressed at 300MPa and sintered in vacuum furnace at temperatures 1450*C. Produced gradient materials were studied by scanning electron microscope (SEM), light microscope. Hardness tests and density examination were also made. Findings: According to carried out researches it could be stated, that forming the gradient materials with highest portion of complex carbide (W,Ti)C 91-95%, using uniaxial unilateral pressing, could be possible after adding into each layer of mixtures 2% of paraffin lubricant. High diversification of cobalt matrix ratio in comparison with hard phases in subsequent layers of gradient materials leads to their deformation in as sintered state. In case of all gradient materials, mean hardness was equal about 1600 HV1. Whereas, hardness of lower cobalt matrix rich layers has value about 1450 HV1 which increases up to 1700 HV1 for lower layer of material rich with hard carbide phases. Practical implications: The Powder Metallurgy gives the possibility of manufacturing tools gradient materials characterised by very high hardness on the surface and relative ductility in core. Originality/value: In the work the manufacturing of TGM on the basis of different portion of cobalt matrix reinforced with hard ceramics particles carried out in order to improve the abrasion resistance and ductility of tool cutting materials.