Wyniki wyszukiwania - BazTech

1

Kucie w matrycach zamkniętych wyprasek z proszku stopu Al-Cu-Si z udziałem fazy ciekłej.

Szczepanik S., Frydrych H., Krawiarz J., Wiśniewski B.

Rudy i Metale Nieżelazne

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2003

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R. 48, nr 10-11

473-479

PL

Jednym z najnowszych procesów kształtowania materiałów jest odkształcanie z udziałem fazy ciekłej, która współistnieje z fazą stałą w stopach podczas ich krzepnięcia lub w wyniku nagrzewania do temperatury pomiędzy solidusem i likwidusem. Poszukuje się w tym procesie takich warunków odkształcania, które umożliwią otrzymanie wyrobów o wysokich własnościach przy małych naciskach jednostkowych podczas jego realizacji. W artykule omówiono zagadnienia związane ze zmianami w strukturze stopu Al8,84%Cu6,33%Si0,65%Mg w zależności od parametrów nagrzewania do kucia, tj. temperatury i czasu wygrzewania oraz wielkości odkształcenia dla wyjściowych materiałów w postaci odlewu oraz wyprasek otrzymanych z proszku. W wyniku badań określono warunki tworzenia się fazy ciekłej w czasie nagrzewania do kucia. Materiał otrzymany z wyjściowego materiału w postaci proszku charakteryzuje się znacznie drobniejszym ziarnem fazy stałej i równomierniejszym rozłożeniem wokół niej fazy ciekłej o składzie eutektycznym w porównaniu do odlewu. Kucie w matrycach zamkniętych w temperaturze 510 i 530 °C wyprasek z proszku stopu Al8,84%Cu6,33%Si0,65%Mg prowadzi do całkowitego zagęszczenia tworzywa. Przeprowadzone badania własności mechanicznych i struktury odkuwek otrzymanych z. wyprasek tego proszku wykazały możliwość wytwarzania w procesie odkształcania z udziałem fazy ciekłej wyrobów o zadowalających własnościach, zależnych od temperatury odkształcania i parametrów obróbki cieplnej po kuciu.

EN

Forming in the semi-solid state, which is present in alloys during their solidification or in effect of heating up to temperature between solidus and liquidus, is one of the latest forming processes. Such forming conditions are being searched for that would enable to obtain products with the required properties using small pressure. Problems connected with changes in the structure of Al8,84%Cu6,33%Si0,65%Mg in dependance of heat treatment conditions, i.e. temperature and heating time and the magnitude of deformation for the material as a cast and compacts from the powder have been discussed. As a result of the research the conditions of appearing of the structure with liquid phase content have been determined. The material obtained from the powder is characterised by finer grain and more even distribution of eutectic mixture around solid phase than the cast. Full densification of PM compacts after closed-die forging at temperature 510 and 530 °C was obtained. Research of mechanical properties and the structure of forgings has shown that the products obtained from PM perform have the required properties, which depend on the forming temperature and heat treatment parameters.

2

Influence of the production parameters on the properties of the sinters made from displaced copper powders.

Leżański J., Gacek S., Radoń A., Olszewska I.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

1203-1205

EN

In this paper the production parameters influence on the properties of sinters made from copper powder which are obtained on the first stage of hydrometallurgical processing by displacing from copper fire scale, are presented. Pressed powder compacts density and sinters density were investigated. Also sinters bending strength, hardness, electric resistance were measured and sinters structure was observed and analysed. In described experiment sinters with very high properties were obtained and this indicate high suitability of the use of hydrometallurgical copper powders for application in powder metallurgy technology.

3

Effect of heating rate on the synthesis of nickel aluminides by reactive sintering.

Gialanella S., Pieczonka T., Molinari A., Kazior J.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

909-912

EN

Dimensional changes occuring during reactive sintering of three different elemental nickel - aluminium powder mixtures were investigated. Sintering process of powder compacts was curried out under vacuum in a horizontal dilatometer at a various heating rates. The synthesis reaction proceeded with a sudden release of heat and sudden dimensional changes, corresponding to the appearance of liquid phase in the system. Heating rate is a crucial parameter affecting the dominant sintering mechanisms: both extensive shrinkage as well as extensive swelling were observed for each investigated mixture composition depending on the actual heating rate. At slower heating rate the synthesis reactions were initiated and developed between solid powders of nickel and aluminium. In these cases, owing to the limited amount of liquid phase which developed, a swelling of compacts was observed. However, at the higher heating rate solid state reactions were limited and after transient swelling also shrinkage was observed.

4

Crystallite orientation distribution analysis of the cold rolled textures of powder iron strip.

Pańta A., Szczepanik S., Chruściel K.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

1219-1222

EN

In this work the results of the texture investigations in cold deformed sintered powder iron strips made from powder WPL-200 type are presented. Textures of starting materials with different densities were measured. These materials were deformed by rolling in deformation range from 0 to 40%. Weak textures were found in powder iron strips no mater what was their starting density.