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1

The influence of HEBM on the structure of Fe-0,8%C alloys

Nowosielski R., Pilarczyk W.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 22, nr 1

33-36

EN

Purpose: The microstructure characterization of iron-carbon powder and sinters is the purpose of this paper. The main aim of this work is to determine structure of Fe-0.8% mass. C alloys. Design/methodology/approach: Iron-carbon powder alloys were produced employing the mixture of crystalline iron and graphite powders in suitable weight relation. The powders were mechanical alloyed and sintered. The pressing and free sintering were applied. The X-ray diffraction, scanning electron microscopy and optical microscopy investigations were performed on Fe-0.8% mass. C alloys. Findings: The application of the mechanical alloying method enables to produce nanocrystalline alloys with amorphous phase. The choose of sinter method have an influence on structure of sinters. The free sintering process in the temperature of 1100 degrees causes the crystallization of cementite and forming of voids. Research limitations/implications: The powder metallurgy techniques make it possible to obtain Fe-C massive materials by means of HEBM (High Energy Ball Milling), followed by compacting and sintering. Further investigations should be concentrate on the developing of powder consolidation method and refinement particles during high energy ball milling. Originality/value: The determination of the relations between the powders and sinters structure is necessary for the proper procedure of material manufacture and indication of the fields of their application.

2

Processing and properties of sinters prepared from 316L steel nanopowders

Krztoń H., Kolesnikow D., Paduch J., Molenda R.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 21, nr 2

73-76

EN

Purpose: The results of the research work on processing the sinters obtained from nanocrystalline powders of 316L steel are presented. Design/methodology/approach: The 316L steel powder has been mechanically alloyed from a set of elementary powders with use of Fritsch Vario-Planetary Mill Pulverisette 4. The time of 12 hours of milling has been needed for producing the powder. The X-ray diffraction has been used for controlling of the mechanical alloying process. The Rietveld method has been used to calculate the contents of the components of the powder. Cold and hot isostatic pressing have been applied to make the compacts. The pressure of 500 MPa and 900 MPa of cold pressing, and 150 MPa of hot pressing have been used. The green compacts have been pressed isostaticaly using liquid aluminium in the temperature of 950 degrees centigrade (1223 K). The X-ray diffraction have been used to identify the phase components of the sinters. The structure of the sinters have been observed using scanning electron microscope. The hardness values have been obtained by Vicker's test. Findings: The mechanically alloyed powder has consisted of about 94 wt.% of austenite, 5 wt.% of ferrite and not more than 1 wt.% of not alloyed molybdenum. Two kinds of sinters have been produced, one kind made of pure 316L powder, second one obtained with aluminium infiltration within the volume of the sinters. The observed porosity of the sinters has depended on the applied pressing conditions strongly, mainly on the value of cold isostatic pressure. The hardness of the first kind of sinters have achieved a value of 380 HV (98N), the hardness of the second kind - more than 400 HV (98N). Practical implications: The Al infiltrated sinter has been proposed as a material for a part of Diesel engine. As an example, a part of a fuel injection has been produced. Originality/value: The nanocrystalline 316L powder has been obtained using mechanical alloying process. The original method of hot isostatic pressing in liquid aluminium has been proposed. This method enables to produce infiltrated sinters with low porosity and high hardness values.

3

Nanocrystalline alloy hydrides formed by mechanical alloying.

Jurczyk M., Nowak M., Jankowska E., Gąsiorowski A.

Inżynieria Materiałowa

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2001

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R. XXII, nr 4

416-418

EN

This article presents the work carried out on nanocrystalline Mg2Ni, LaNi5, ZrV2 and TiFe phases, which were prepared by mechanical alloying (MA) and then annealing. XRD analysis showed that, after -40 h milling the studied alloys have decomposed into amorphous phases. Following annealing in high purity argon, XRD confirmed the formation of ordered materials. These alloys were used as active materials for the negative electrodes of an alkaline, rechargeable nickel-metal hydride (Ni-NHx) batteries. The electrochemical results show the substantial difference between the nanocrystalline and the amorphous powders. For example, in the nanocrystalline TiFe0.5Ni0.5 powders discharging capacities up to 125 mA h g to the -1 (at 40 mA g to the -1discharge current) have been measured. MA process has recently emerged as a novel technique for producing nanostructured alloy powders with interesting electrochemical properties.

4

Wpływ modyfikacji powierzchniowej cząstek na strukturę kompozytów odlewanych AlMg4-(Al-Al2O3)p.

Olszówka-Myalska A., Śleziona J., Formanek B., Myalski J.

Inżynieria Materiałowa

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2000

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R. XXI, nr 6

379-382

PL

Określono wpływ obróbki powierzchniowej zbrojenia, jako elementu technologii wytwarzania kompozytu, na rozmieszczenie cząstek Al-Al2O3 w stopie AlMg4 oraz strukturę połączenia cząstki kompozytowe-stop. Odlewany materiał kompozytowy wytworzono wprowadzając do ciekłego stopu AlMg4 cząstki kompozytowe Al-Al2O3 otrzymane metodą MA przy użyciu młyna rotacyjno-wibracyjnego. Zastosowano cząstki kompozytowe bez dodatkowej modyfikacji powierzchniowej oraz modyfikowane dwoma sposobami - przy pomocy NaOH oraz związkami boru. W zależności od warunków mieszania, temperatury odlewania i innych parametrów procesu otrzymano równomierne lub zróżnicowane rozmieszczenie proszku kompozytowego w odlewie. W odróżnieniu od klasycznych zawiesin stop Al - cząstki Al2O3 stwierdzono, że można wprowadzać proszek kompozytowy (Al-Al2O3)p do ciekłego AlMg4 bez powierzchniowej modyfikacji, a modyfikacja NaOH oraz modyfikacja związkami boru powodowała powstanie połączenia cząstki - AlMg4 o niekorzystnej strukturze.

EN

The influence of surface treatment of composite powder on distribution of composite powder (Al-Al2O3)p in AlMg4 matrix and bonding between composite powder and AlMg4 alloy was analysed. Composite casts were produced by stirring of molten AlMg4 alloy and (Al-Al2O3)p composite powder obtained in vibration-rotary mill (MA method). Composite powders without any surface modification and with two kinds of preparation in NaOH and in boron compounds were used. In dependence on stirring conditions, casting temperature and other technological parameters uniform or gradient distribution of composite powder was observed. In the difference from classical molten aluminium - Al2O3 particles mixture it has been found that it is possible to introduce (Al-Al2O3)p composite powders into liquid AlMg4 without their surface modification and the modification with NaOH and boron compounds caused the composite particle - AlMg4 interface with disadvantageous structure.